Start with copy of whiteboard

50 files changed, 4008 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100755
index 0000000..aafa42a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,88 @@
+#
+# Makefile
+#
+# Environment: Debian
+#
+
+include common.mk
+
+PROJECTNAME=whiteboard
+
+DISTROS=base debian11 ubuntu2210
+TGZNAME=$(PROJECTNAME)-$(VERSION).tar.xz
+
+INCLUDES=-I.
+HEADERS=config.h qrcode.h storage.h whiteboard.h compiledsql.h connectionregistry.h diff.h
+SOURCES=$(HEADERS:.h=.cpp)
+OBJECTS=$(HEADERS:.h=.o)
+TARGETS=whiteboard
+
+build: $(TARGETS)
+	$(MAKE) -C webassembly
+
+all: build
+	./whiteboard -c whiteboard.conf
+
+install:
+	mkdir -p $(DESTDIR)/usr/bin
+	cp whiteboard $(DESTDIR)/usr/bin
+	
+	mkdir -p $(DESTDIR)/usr/lib/whiteboard/html
+	cp -r html/* $(DESTDIR)/usr/lib/whiteboard/html/
+	
+	uglifyjs html/whiteboard.js -m -c > $(DESTDIR)/usr/lib/whiteboard/html/whiteboard.js || cp html/whiteboard.js $(DESTDIR)/usr/lib/whiteboard/html/whiteboard.js
+	htmlmin html/index.html $(DESTDIR)/usr/lib/whiteboard/html/index.html
+	cleancss -o $(DESTDIR)/usr/lib/whiteboard/html/whiteboard.css html/whiteboard.css
+	
+	mkdir -p $(DESTDIR)/etc
+	cp whiteboard.conf $(DESTDIR)/etc
+
+# link
+whiteboard: $(OBJECTS) main.o
+	$(CXX) $(LDFLAGS) $^ $(LDLIBS) $(LIBS) -o $@
+
+# .cpp -> .o
+%.o: %.cpp
+	$(CXX) $(CXXFLAGS) $(INCLUDES) -c $< -o $@
+
+test:
+	$(MAKE) -C tests
+
+clean:
+	-rm -f *.o $(TARGETS) *.gcov
+	-rm -f html/libwhiteboard.wasm html/libwhiteboard.js
+	$(MAKE) -C tests clean
+	$(MAKE) -C webassembly clean
+
+deb:
+	dpkg-buildpackage
+
+deb-src: clean
+	dh_clean
+	dh_auto_clean
+	dpkg-source -b -I.git -Iresult .
+
+$(DISTROS): deb-src
+	sudo pbuilder build --basetgz /var/cache/pbuilder/$@.tgz --buildresult result/$@ ../$(PROJECTNAME)_$(VERSION).dsc
+	debsign result/$@/$(PROJECTNAME)_$(VERSION)_amd64.changes
+
+DISTFILES=$(shell git ls-files 2>/dev/null)
+
+dist: clean
+	rm -rf $(PROJECTNAME)-$(VERSION)
+	mkdir $(PROJECTNAME)-$(VERSION)
+	cp --parents -r $(DISTFILES) $(PROJECTNAME)-$(VERSION)
+	tar cfJ ../$(PROJECTNAME)-$(VERSION).tar.xz $(PROJECTNAME)-$(VERSION)
+	rm -rf $(PROJECTNAME)-$(VERSION)
+	ls -l ../$(PROJECTNAME)-$(VERSION).tar.xz
+
+upload: dist
+	scp ../$(TGZNAME) antcom.de:/var/www/reichwein.it-download/
+	scp -r result antcom.de:
+	scp -r remote-install.sh antcom.de:
+	ssh antcom.de ./remote-install.sh $(PROJECTNAME) $(VERSION)
+	ssh antcom.de rm -rf remote-install.sh result
+
+debs: $(DISTROS)
+
+.PHONY: clean
diff --git a/common.mk b/common.mk
new file mode 100644
index 0000000..5f4c77c
--- /dev/null
+++ b/common.mk
@@ -0,0 +1,71 @@
+CXX=clang++-14
+#CXX=g++-12
+
+ifeq ($(shell which $(CXX)),)
+CXX=clang++-13
+endif
+
+ifeq ($(shell which $(CXX)),)
+CXX=clang++-11
+endif
+
+ifeq ($(shell which $(CXX)),)
+CXX=clang++-10
+endif
+
+ifeq ($(shell which $(CXX)),)
+CXX=clang++
+endif
+
+ifeq ($(shell which $(CXX)),)
+CXX=g++-9
+endif
+
+ifeq ($(shell which $(CXX)),)
+CXX=g++
+endif
+
+ifeq ($(CXXFLAGS),)
+CXXFLAGS=-g -O2
+endif
+
+CXXFLAGS+=-Wall -fPIE -Wpedantic -gdwarf-4
+LDFLAGS+=-pie
+
+ifeq ($(CXX),g++-9)
+CXXFLAGS+=-std=c++17
+else
+CXXFLAGS+=-std=c++20
+endif
+
+ifeq ($(CXX),clang++-10)
+LIBS+=-fuse-ld=lld-10 -lstdc++
+CXXTYPE=clang++
+else ifeq ($(CXX),clang++-11)
+#LIBS+=-fuse-ld=lld-11 -lc++ -lc++abi
+LLVMPROFDATA=llvm-profdata-11
+LLVMCOV=llvm-cov-11
+CXXTYPE=clang++
+else ifeq ($(CXX),clang++-14)
+#LIBS+=-fuse-ld=lld-14 -lc++ -lc++abi
+LLVMPROFDATA=llvm-profdata-14
+LLVMCOV=llvm-cov-14
+CXXTYPE=clang++
+else
+LIBS+=-lstdc++ -lstdc++fs
+CXXTYPE=g++
+endif
+
+CXXFLAGS+=$(shell pkg-config --cflags qrcodegencpp GraphicsMagick++ fmt sqlite3)
+LIBS+=-lboost_filesystem -lpthread
+LIBS+=-lSQLiteCpp $(shell pkg-config --libs qrcodegencpp GraphicsMagick++ fmt sqlite3)
+LIBS+=-lreichwein
+
+SRC_ROOT=$(shell echo $(MAKEFILE_LIST) | tr " " "\n" | grep common.mk | sed -e 's/\([^ ]*\)common.mk/\1/g')
+ifeq ($(SRC_ROOT),)
+SRC_ROOT=.
+endif
+
+VERSION=$(shell dpkg-parsechangelog --show-field Version --file $(SRC_ROOT)/debian/changelog)
+CXXFLAGS+=-DWHITEBOARD_VERSION=\"$(VERSION)\"
+
diff --git a/compiledsql.cpp b/compiledsql.cpp
new file mode 100644
index 0000000..b8d6d70
--- /dev/null
+++ b/compiledsql.cpp
@@ -0,0 +1,46 @@
+#include "compiledsql.h"
+
+#include <iostream>
+
+#include <boost/algorithm/string/predicate.hpp>
+
+CompiledSQL::CompiledSQL(SQLite::Database& db, const std::string& stmt):
+ m_db{db},
+ m_query{stmt},
+ m_stmt{},
+ m_isSelect{}
+{
+ if (
+#if __cplusplus >= 202002
+     stmt.starts_with("SELECT ")
+#else
+     boost::algorithm::starts_with(stmt, "SELECT ")
+#endif
+     ) {
+  m_isSelect = true;
+ } else {
+  m_isSelect = false;
+ }
+}
+
+bool CompiledSQL::execute()
+{
+ if (m_isSelect) {
+  return m_stmt->executeStep();
+ } else {
+  return m_stmt->exec();
+ }
+}
+
+CompiledSQL::Guard::Guard(CompiledSQL& cs): m_cs{cs}
+{
+ if (!m_cs.m_stmt) {
+  m_cs.m_stmt = std::make_shared<SQLite::Statement>(m_cs.m_db, m_cs.m_query);
+ }
+}
+
+CompiledSQL::Guard::~Guard()
+{
+ m_cs.m_stmt->reset();
+}
+
diff --git a/compiledsql.h b/compiledsql.h
new file mode 100644
index 0000000..bb1062c
--- /dev/null
+++ b/compiledsql.h
@@ -0,0 +1,45 @@
+// Helper Class for SQLite backed storage
+
+#pragma once
+
+#include <memory>
+
+#include <SQLiteCpp/SQLiteCpp.h>
+
+class CompiledSQL
+{
+public:
+ CompiledSQL(SQLite::Database& db, const std::string& stmt);
+ 
+ // index 1-based as in SQLite
+ template<typename T>
+ void bind(int index, T value)
+ {
+  m_stmt->bind(index, value);
+ }
+
+ bool execute();
+
+ // index 0-based as in SQLite
+ template<typename T>
+ T getColumn(const int index)
+ {
+  return m_stmt->getColumn(index);
+ }
+
+ class Guard
+ {
+ public:
+  Guard(CompiledSQL& cs);
+  ~Guard();
+ private:
+  CompiledSQL& m_cs;
+ };
+
+private:
+ SQLite::Database& m_db;
+ std::string m_query;
+ std::shared_ptr<SQLite::Statement> m_stmt;
+ bool m_isSelect; // In SQLite, SELECT statements will be handled w/ executeStep(), others w/ exec()
+};
+
diff --git a/config.cpp b/config.cpp
new file mode 100644
index 0000000..afb5cd2
--- /dev/null
+++ b/config.cpp
@@ -0,0 +1,83 @@
+#include "config.h"
+
+#include <boost/property_tree/ptree.hpp>
+#include <boost/property_tree/xml_parser.hpp>
+
+#include <iostream>
+#include <string>
+
+namespace pt = boost::property_tree;
+using namespace std::string_literals;
+
+namespace {
+ const std::string default_datapath {"/var/lib/whiteboard"};
+ const uint64_t default_maxage{0}; // timeout in seconds; 0 = no timeout
+ const std::string default_listen {"::1:9000"};
+ const int default_threads{1};
+ const int default_max_connections{1000};
+}
+
+Config::Config(const std::string& config_filename):
+ m_dataPath{default_datapath},
+ m_maxage{default_maxage},
+ m_listenAddress{"::1"},
+ m_listenPort{9000},
+ m_threads{default_threads},
+ m_max_connections{default_max_connections}
+{
+
+ try {
+  pt::ptree tree;
+
+  pt::read_xml(config_filename, tree, pt::xml_parser::no_comments | pt::xml_parser::trim_whitespace);
+
+  m_dataPath = tree.get<std::string>("config.datapath", default_datapath);
+  m_maxage = tree.get<uint64_t>("config.maxage", default_maxage);
+  std::string listen {tree.get<std::string>("config.port", default_listen)};
+  auto pos{listen.find_last_of(':')};
+  if (pos == std::string::npos)
+   throw std::runtime_error("Bad port address: "s + listen);
+
+  m_listenAddress = listen.substr(0, pos);
+  m_listenPort = std::stoi(listen.substr(pos + 1));
+  if (m_listenPort < 0 || m_listenPort > 65535)
+   throw std::runtime_error("Bad listen port: "s + std::to_string(m_listenPort));
+
+  m_threads = tree.get<int>("config.threads", default_threads);
+  
+  m_max_connections = tree.get<int>("config.maxconnections", default_max_connections);
+ } catch (const std::exception& ex) {
+  std::cerr << "Error reading config file " << config_filename << ". Using defaults." << std::endl;
+ }
+}
+
+std::string Config::getDataPath() const
+{
+ return m_dataPath;
+}
+
+uint64_t Config::getMaxage() const
+{
+ return m_maxage;
+}
+
+std::string Config::getListenAddress() const
+{
+ return m_listenAddress;
+}
+
+int Config::getListenPort() const
+{
+ return m_listenPort;
+}
+
+int Config::getThreads() const
+{
+ return m_threads;
+}
+
+int Config::getMaxConnections() const
+{
+ return m_max_connections;
+}
+
diff --git a/config.h b/config.h
new file mode 100644
index 0000000..ce2fceb
--- /dev/null
+++ b/config.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <string>
+
+const std::string default_config_filename{"/etc/whiteboard.conf"};
+
+class Config
+{
+private:
+ std::string m_dataPath;
+ uint64_t m_maxage;
+ std::string m_listenAddress; // ip address v4/v6
+ int m_listenPort;
+ int m_threads;
+ int m_max_connections;
+
+public:
+ Config(const std::string& config_filename = default_config_filename);
+ std::string getDataPath() const;
+ uint64_t getMaxage() const;
+ 
+ std::string getListenAddress() const;
+ int getListenPort() const;
+
+ int getThreads() const;
+
+ int getMaxConnections() const;
+};
diff --git a/connectionregistry.cpp b/connectionregistry.cpp
new file mode 100644
index 0000000..e3c0c11
--- /dev/null
+++ b/connectionregistry.cpp
@@ -0,0 +1,110 @@
+#include "connectionregistry.h"
+
+#include <iostream>
+#include <utility>
+
+void ConnectionRegistry::setId(ConnectionRegistry::connection c, const std::string& id)
+{
+ if (!m_connections.at(c).empty()) {
+  auto& connections_set{m_ids.at(id)};
+  connections_set.erase(c);
+  if (connections_set.empty())
+   m_ids.erase(id);
+ }
+ 
+ m_connections.at(c) = id;
+
+ if (!id.empty()) {
+  if (!m_ids.contains(id))
+   m_ids[id] = {};
+  m_ids.at(id).insert(c);
+ }
+
+}
+
+void ConnectionRegistry::addConnection(ConnectionRegistry::connection c)
+{
+ if (m_connections.contains(c))
+  throw std::runtime_error("ConnectionRegistry::addConnection: connection already exists");
+
+ m_connections.emplace(c, "");
+
+ std::cout << "Info: Added connection, now " << m_connections.size() << std::endl;
+}
+
+void ConnectionRegistry::delConnection(ConnectionRegistry::connection c)
+{
+ if (!m_connections.contains(c))
+  throw std::runtime_error("ConnectionRegistry::delConnection: connection doesn't exist");
+
+ std::string id {m_connections.at(c)};
+
+ m_connections.erase(c);
+
+ if (!id.empty()) {
+  auto& connections_set{m_ids.at(id)};
+  connections_set.erase(c);
+  if (connections_set.empty())
+   m_ids.erase(id);
+ }
+ 
+ std::cout << "Info: Deleted connection, now " << m_connections.size() << std::endl;
+}
+
+std::unordered_set<ConnectionRegistry::connection>::iterator ConnectionRegistry::begin(const std::string& id)
+{
+ return m_ids.at(id).begin();
+}
+
+std::unordered_set<ConnectionRegistry::connection>::iterator ConnectionRegistry::end(const std::string& id)
+{
+ return m_ids.at(id).end();
+}
+
+std::unordered_map<ConnectionRegistry::connection, std::string>::iterator ConnectionRegistry::begin()
+{
+ return m_connections.begin();
+}
+
+std::unordered_map<ConnectionRegistry::connection, std::string>::iterator ConnectionRegistry::end()
+{
+ return m_connections.end();
+}
+
+void ConnectionRegistry::dump() const
+{
+ std::cout << "Connection Registry:" << std::endl;
+ 
+ std::cout << "Connections: " << std::endl;
+ for (auto& i: m_connections) {
+  std::cout << "    " << i.first << ": " << i.second << std::endl;
+ }
+ 
+ std::cout << "IDs: " << std::endl;
+ for (auto& i: m_ids) {
+  std::cout << "    " << i.first << ":";
+
+  for (auto& j: i.second) {
+   std::cout << " " << j;
+  }
+  std::cout << std::endl;
+ }
+}
+
+size_t ConnectionRegistry::number_of_connections() const
+{
+ return m_connections.size();
+}
+
+ConnectionRegistry::RegistryGuard::RegistryGuard(ConnectionRegistry& registry, ConnectionRegistry::connection c):
+ m_registry{registry},
+ m_connection{c}
+{
+ m_registry.addConnection(m_connection);
+}
+
+ConnectionRegistry::RegistryGuard::~RegistryGuard()
+{
+ m_registry.delConnection(m_connection);
+}
+
diff --git a/connectionregistry.h b/connectionregistry.h
new file mode 100644
index 0000000..c3c6884
--- /dev/null
+++ b/connectionregistry.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <algorithm>
+#include <memory>
+#include <unordered_map>
+#include <unordered_set>
+
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/beast/websocket.hpp>
+
+class ConnectionRegistry
+{
+public:
+ using connection = std::shared_ptr<boost::beast::websocket::stream<boost::asio::ip::tcp::socket>>;
+
+ ConnectionRegistry() = default;
+ ~ConnectionRegistry() = default;
+
+ void setId(connection c, const std::string& id);
+
+ // used via RegistryGuard
+ void addConnection(connection c);
+ void delConnection(connection c);
+
+ // iterate over all connections associated with a certain id
+ std::unordered_set<connection>::iterator begin(const std::string& id);
+ std::unordered_set<connection>::iterator end(const std::string& id);
+
+ // iterate over all connections
+ std::unordered_map<connection, std::string>::iterator begin();
+ std::unordered_map<connection, std::string>::iterator end();
+ 
+ void dump() const;
+
+ size_t number_of_connections() const;
+
+private:
+ // map connection to id
+ std::unordered_map<connection, std::string> m_connections;
+ // map id to list of related connections, used for iteration over connections to notify about changes
+ std::unordered_map<std::string, std::unordered_set<connection>> m_ids;
+
+public:
+ class RegistryGuard
+ {
+ public:
+  RegistryGuard(ConnectionRegistry& registry, connection c);
+  ~RegistryGuard();
+ private:
+  ConnectionRegistry& m_registry;
+  connection m_connection;
+ };
+
+};
+
diff --git a/debian/README.Debian b/debian/README.Debian
new file mode 100644
index 0000000..7450383
--- /dev/null
+++ b/debian/README.Debian
@@ -0,0 +1,51 @@
+whiteboard for Debian
+=====================
+
+This package is the Debian version of whiteboard.
+
+It is a websocket application communicating to a webserver, e.g. Reichwein.IT webserver.
+
+Via cron or systemd, whiteboard data in /var/lib/whiteboard is cleaned up once a day.
+Data location and maximum data age can be configured via /etc/whiteboard.conf.
+
+Configuration
+-------------
+
+* You can add this to /etc/webserver.conf
+
+   <path requested="/whiteboard">
+    <plugin>static-files</plugin>
+    <target>/usr/lib/whiteboard/html</target>
+   </path>
+   <path requested="/whiteboard/websocket">
+    <plugin>websocket</plugin>
+    <target>127.0.0.1:9014</target>
+   </path>
+
+* Edit /etc/whiteboard.conf to adjust the whiteboard data path if different
+  from /var/lib/whiteboard
+
+* Enable:
+
+  # systemctl enable whiteboard.service
+
+* Start:
+
+  # systemctl start whiteboard
+
+* Stop:
+
+  # systemctl stop whiteboard
+
+* Query Status:
+
+  # systemctl status whiteboard
+
+  and observe /var/log/syslog
+
+
+Contact
+-------
+
+Reichwein IT <mail@reichwein.it>
+
diff --git a/debian/changelog b/debian/changelog
new file mode 100644
index 0000000..de01abe
--- /dev/null
+++ b/debian/changelog
@@ -0,0 +1,75 @@
+whiteboard (1.9) UNRELEASED; urgency=medium
+
+  * Updated build environment
+  * Added missing image files
+
+ -- Roland Reichwein <mail@reichwein.it>  Mon, 20 Feb 2023 10:10:27 +0100
+
+whiteboard (1.8) unstable; urgency=medium
+
+  * Added config.maxconnections, defaults to 1000
+  * Fixed package dependencies for PDF generation
+  * Touch documents on read (i.e. reset timeout on read)
+  * Validate id, server-side
+
+ -- Roland Reichwein <mail@reichwein.it>  Sun, 19 Feb 2023 18:42:32 +0100
+
+whiteboard (1.7) unstable; urgency=medium
+
+  * Fix crash on stats.html page reload/close
+  * Focus on reconnect button
+  * Added Markdown to PDF download via pandoc
+
+ -- Roland Reichwein <mail@reichwein.it>  Fri, 10 Feb 2023 18:01:37 +0100
+
+whiteboard (1.6) unstable; urgency=medium
+
+  * Added stats.html
+  * Use boost strands instead of mutex
+
+ -- Roland Reichwein <mail@reichwein.it>  Mon, 06 Feb 2023 07:58:39 +0100
+
+whiteboard (1.5) unstable; urgency=medium
+
+  * Move from FCGI to websocket interface
+  * Position changes w/o file transmit
+  * Print version on main page
+  * Add reconnect button
+  * Add diff handling
+
+ -- Roland Reichwein <mail@reichwein.it>  Mon, 30 Jan 2023 21:05:35 +0100
+
+whiteboard (1.4) unstable; urgency=medium
+
+  * Move from filesystem based documents to sqlite
+  * Add tests
+  * Separated out libreichwein
+
+ -- Roland Reichwein <mail@reichwein.it>  Sat, 21 Jan 2023 12:20:20 +0100
+
+whiteboard (1.3) unstable; urgency=medium
+
+  * Page design (center)
+  * Follow editor's cursor
+
+ -- Roland Reichwein <mail@reichwein.it>  Mon, 05 Dec 2022 19:22:27 +0100
+
+whiteboard (1.2) unstable; urgency=medium
+
+  * Fix build on Debian 11
+  * UglifyJS on best-effort base
+
+ -- Roland Reichwein <mail@reichwein.it>  Sat, 03 Dec 2022 17:03:11 +0100
+
+whiteboard (1.1) unstable; urgency=medium
+
+  * Compress Javascript
+  * Add QR Code
+
+ -- Roland Reichwein <mail@reichwein.it>  Sat, 03 Dec 2022 16:10:06 +0100
+
+whiteboard (1.0) unstable; urgency=medium
+
+  * Initial release
+
+ -- Roland Reichwein <mail@reichwein.it>  Sat, 05 Nov 2022 13:34:57 +0100
diff --git a/debian/compat b/debian/compat
new file mode 100644
index 0000000..48082f7
--- /dev/null
+++ b/debian/compat
@@ -0,0 +1 @@
+12
diff --git a/debian/control b/debian/control
new file mode 100644
index 0000000..9c75069
--- /dev/null
+++ b/debian/control
@@ -0,0 +1,16 @@
+Source: whiteboard
+Section: web
+Priority: optional
+Maintainer: Roland Reichwein <mail@reichwein.it>
+Build-Depends: debhelper (>= 12), libboost-all-dev | libboost1.71-all-dev, clang | g++-9, llvm | g++-9, lld | g++-9, uglifyjs, python3-pkg-resources, htmlmin, cleancss, libqrcodegencpp-dev, libgraphicsmagick++-dev, pkg-config, libfmt-dev, libsqlitecpp-dev, googletest, gcovr, libreichwein-dev, emscripten
+Standards-Version: 4.5.0
+Homepage: http://www.reichwein.it/whiteboard/
+
+Package: whiteboard
+Architecture: any
+Depends: ${shlibs:Depends}, ${misc:Depends}, libxml2-utils, pandoc, texlive-latex-recommended, texlive-latex-extra
+Recommends: webserver
+Homepage: http://www.reichwein.it/whiteboard/
+Description: Web application for an collaborative editor
+ Whiteboard is a text editor running on an HTML5 webpage (including a server
+ part) that enables collaborative editing and presenting.
diff --git a/debian/copyright b/debian/copyright
new file mode 100644
index 0000000..5007f59
--- /dev/null
+++ b/debian/copyright
@@ -0,0 +1,4 @@
+Author: Roland Reichwein <mail@reichwein.it>, 2022
+
+Both upstream source code and Debian packaging is available
+under the conditions of CC0 1.0 Universal
diff --git a/debian/rules b/debian/rules
new file mode 100755
index 0000000..72c5b8c
--- /dev/null
+++ b/debian/rules
@@ -0,0 +1,13 @@
+#!/usr/bin/make -f
+
+%:
+	dh $@
+
+override_dh_fixperms:
+	dh_fixperms
+	chmod a+rwx debian/whiteboard/var/lib/whiteboard
+
+
+override_dh_auto_install:
+	dh_auto_install
+	dh_installsystemd --name whiteboard
diff --git a/debian/source/format b/debian/source/format
new file mode 100644
index 0000000..89ae9db
--- /dev/null
+++ b/debian/source/format
@@ -0,0 +1 @@
+3.0 (native)
diff --git a/debian/whiteboard.conf b/debian/whiteboard.conf
new file mode 100644
index 0000000..6446d39
--- /dev/null
+++ b/debian/whiteboard.conf
@@ -0,0 +1,34 @@
+<config>
+ <!--
+  datapath: location in filesystem to store whiteboard data
+  Example: /var/lib/whiteboard
+ -->
+ <datapath>/var/lib/whiteboard</datapath>
+
+ <!--
+  port: socket to listen on for websocket
+  Example: ::1:8765
+ -->
+ <port>::1:8765</port>
+
+ <!--
+  Maximum age of individual whiteboard pages in seconds.
+  Older pages will be removed by whiteboard-cleanup and crond.
+  Example: 2592000 (~30 days)
+ -->
+ <maxage>2592000</maxage>
+ 
+ <!--
+  Number of threads to use
+  Example: 4
+ -->
+ <threads>4</threads>
+ 
+ <!--
+  Maximum number of total concurrent websocket connections. Above this limit,
+  new connections will be rejected until old ones are closed.
+  Example: 500
+  Default: 1000
+ -->
+ <maxconnections>500</maxconnections>
+</config>
diff --git a/debian/whiteboard.dirs b/debian/whiteboard.dirs
new file mode 100644
index 0000000..7b03c85
--- /dev/null
+++ b/debian/whiteboard.dirs
@@ -0,0 +1 @@
+var/lib/whiteboard
diff --git a/debian/whiteboard.docs b/debian/whiteboard.docs
new file mode 100644
index 0000000..0812baa
--- /dev/null
+++ b/debian/whiteboard.docs
@@ -0,0 +1 @@
+webserver.conf.example
diff --git a/debian/whiteboard.whiteboard.service b/debian/whiteboard.whiteboard.service
new file mode 100644
index 0000000..b41e655
--- /dev/null
+++ b/debian/whiteboard.whiteboard.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=Whiteboard
+After=network.target
+
+[Service]
+Type=simple
+# Restart=always
+ExecStart=/usr/bin/whiteboard
+
+Restart=always
+
+[Install]
+WantedBy=multi-user.target
diff --git a/diff.cpp b/diff.cpp
new file mode 100644
index 0000000..6ac24e7
--- /dev/null
+++ b/diff.cpp
@@ -0,0 +1,188 @@
+#include "diff.h"
+
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+
+#include <boost/property_tree/xml_parser.hpp>
+
+namespace pt = boost::property_tree;
+
+Diff::Diff()
+{
+}
+
+Diff::Diff(const std::string& old_version, const std::string& new_version)
+{
+ create(old_version, new_version);
+}
+
+std::string Diff::apply(const std::string& old_version) const
+{
+ std::string result{old_version};
+
+ if (m_pos0 <= m_pos1 && m_pos1 <= old_version.size()) {
+  result.erase(m_pos0, m_pos1 - m_pos0);
+  result.insert(m_pos0, m_data);
+ }
+ 
+ return result;
+}
+
+void Diff::create(const std::string& old_version, const std::string& new_version)
+{
+ auto front_mismatch{std::mismatch(old_version.cbegin(), old_version.cend(), new_version.cbegin(), new_version.cend())};
+ std::string::difference_type old_pos0 {front_mismatch.first - old_version.cbegin()};
+ auto& new_pos0 {old_pos0};
+
+ // equal
+ if (old_pos0 == old_version.size() && new_pos0 == new_version.size()) {
+  m_pos0 = 0;
+  m_pos1 = 0;
+  m_data.clear();
+  return;
+ }
+
+ // append at end
+ if (old_pos0 == old_version.size()) {
+  m_pos0 = old_pos0;
+  m_pos1 = old_pos0;
+  m_data = new_version.substr(new_pos0);
+  return;
+ }
+
+ // remove from end
+ if (new_pos0 == new_version.size()) {
+  m_pos0 = old_pos0;
+  m_pos1 = old_version.size();
+  m_data.clear();
+  return;
+ }
+
+ auto back_mismatch{std::mismatch(old_version.crbegin(), old_version.crend(), new_version.crbegin(), new_version.crend())};
+ // i.e. the indices starting from which we can assume equality
+ size_t old_pos1 {old_version.size() - (back_mismatch.first - old_version.crbegin())};
+ size_t new_pos1 {new_version.size() - (back_mismatch.second - new_version.crbegin())};
+
+ // complete equality is already handled above
+ 
+ // insert at start
+ if (old_pos1 == 0) {
+  m_pos0 = 0;
+  m_pos1 = 0;
+  m_data = new_version.substr(0, new_pos1);
+  return;
+ }
+
+ // remove from start
+ if (new_pos1 == 0) {
+  m_pos0 = 0;
+  m_pos1 = old_pos1;
+  m_data.clear();
+  return;
+ }
+
+ // re-adjust if search crossed
+ if (old_pos0 > old_pos1) {
+  old_pos0 = old_pos1;
+  new_pos0 = old_pos1;
+ }
+ if (new_pos0 > new_pos1) {
+  old_pos0 = new_pos1;
+  new_pos0 = new_pos1;
+ }
+
+ // insert in the middle
+ if (old_pos0 == old_pos1) {
+  m_pos0 = old_pos0;
+  m_pos1 = old_pos0;
+  m_data = new_version.substr(new_pos0, new_pos1 - new_pos0);
+  return;
+ }
+ 
+ // remove from the middle
+ if (new_pos0 == new_pos1) {
+  m_pos0 = old_pos0;
+  m_pos1 = old_pos1;
+  m_data.clear();
+  return;
+ }
+
+ // last resort: remove and add in the middle
+ m_pos0 = old_pos0;
+ m_pos1 = old_pos1;
+ m_data = new_version.substr(old_pos0, new_pos1 - new_pos0);
+}
+
+Diff::Diff(const boost::property_tree::ptree& ptree)
+{
+ create(ptree);
+}
+
+void Diff::create(const boost::property_tree::ptree& ptree)
+{
+ m_pos0 = ptree.get<int>("diff.start");
+ m_pos1 = ptree.get<int>("diff.end");
+
+ if (m_pos0 > m_pos1)
+  throw std::runtime_error("Bad range in diff");
+
+ m_data = ptree.get<std::string>("diff.data");
+}
+
+Diff::Diff(const std::string& xml)
+{
+ create(xml);
+}
+
+void Diff::create(const std::string& xml)
+{
+ pt::ptree ptree;
+ std::istringstream ss{xml};
+ pt::read_xml(ss, ptree);
+
+ create(ptree);
+}
+
+bool Diff::empty() const
+{
+ return m_pos0 == m_pos1 && m_data.empty();
+}
+
+boost::property_tree::ptree Diff::get_structure() const
+{
+ pt::ptree ptree;
+ ptree.put("diff.start", std::to_string(m_pos0));
+ ptree.put("diff.end", std::to_string(m_pos1));
+ ptree.put("diff.data", m_data);
+
+ return ptree;
+}
+
+std::string Diff::get_xml() const
+{
+ pt::ptree ptree{get_structure()};
+
+ std::ostringstream oss;
+ // write_xml_element instead of write_xml to omit <!xml...> header
+ //pt::xml_parser::write_xml(oss, xml);
+ pt::xml_parser::write_xml_element(oss, {}, ptree, -1, boost::property_tree::xml_writer_settings<pt::ptree::key_type>{});
+ return oss.str();
+}
+
+extern "C" {
+
+ const char* diff_create(const char* old_version, const char* new_version)
+ {
+  Diff diff{old_version, new_version};
+  return strdup(diff.get_xml().c_str());
+ }
+
+ const char* diff_apply(const char* old_version, const char* diff)
+ {
+  Diff d{diff};
+
+  return strdup(d.apply(old_version).c_str());
+ }
+
+}
diff --git a/diff.h b/diff.h
new file mode 100644
index 0000000..5c2c335
--- /dev/null
+++ b/diff.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <string>
+
+#include <boost/property_tree/ptree.hpp>
+
+class Diff
+{
+public:
+ Diff();
+ Diff(const std::string& old_version, const std::string& new_version);
+ void create(const std::string& old_version, const std::string& new_version);
+
+ Diff(const boost::property_tree::ptree& ptree);
+ void create(const boost::property_tree::ptree& ptree);
+
+ Diff(const std::string& xml);
+ void create(const std::string& xml);
+
+ std::string apply(const std::string& old_version) const;
+
+ bool empty() const;
+
+ boost::property_tree::ptree get_structure() const;
+ std::string get_xml() const;
+
+private:
+ // diff replaces space from m_pos0 (inclusive) to m_pos1 (exclusive) with m_data
+ size_t m_pos0{};
+ size_t m_pos1{};
+ std::string m_data;
+};
+
+extern "C" {
+ const char* diff_create(const char* old_version, const char* new_version);
+ const char* diff_apply(const char* old_version, const char* diff);
+}
diff --git a/html/banner256.png b/html/banner256.png
new file mode 100644
index 0000000..89efb4f
--- /dev/null
+++ b/html/banner256.png
diff --git a/html/index.html b/html/index.html
new file mode 100644
index 0000000..b72e23b
--- /dev/null
+++ b/html/index.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<meta charset="utf-8"/>
+		<meta name="viewport" content="width=device-width, initial-scale=1">
+		<meta name="keywords" content="Reichwein, Whiteboard">
+		<title>Reichwein Whiteboard</title>
+		<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon"/>
+		<link rel="stylesheet" type="text/css" href="whiteboard.css"/>
+		<script src="libwhiteboard.js"></script>
+		<script src="whiteboard.js"></script>
+	</head>
+	<body onload="init();">
+                <div class="qrwindow" id="qrwindow" hidden>
+			<img class="qrcode" id="qrcode"></img>
+                </div>
+		<div class="page">
+			<h1><img class="banner" src="banner256.png" alt="Reichwein.IT"/> Whiteboard</h1>
+                        <textarea id="board" name="board"></textarea>
+			<br/>
+			<br/>
+			<button class="button" onclick="on_new_page();">New page</button>
+			<button class="button" onclick="on_qrcode_click();">QR code</button>
+			<span id="status">Starting up...</span>
+			<button class="buttonred" id="reconnect" onclick="on_reconnect_click();" hidden>Reconnect</button>
+			<span class="helper"></span><img class="center-img clickable" onclick="on_pdf_click();" src="pdf-icon-30.png" height="37" width="30"/></span>
+			<br/>
+			<br/>
+                        Reichwein.IT Whiteboard <span id="version"></span> by <a href="https://www.reichwein.it">https://www.reichwein.it</a><br/>
+		</div>
+
+		<a id="download-a" hidden></a>
+	</body>
+</html>
diff --git a/html/pdf-icon-100.png b/html/pdf-icon-100.png
new file mode 100644
index 0000000..9a20387
--- /dev/null
+++ b/html/pdf-icon-100.png
diff --git a/html/pdf-icon-30.png b/html/pdf-icon-30.png
new file mode 100644
index 0000000..5f60d2f
--- /dev/null
+++ b/html/pdf-icon-30.png
diff --git a/html/pdf-icon-50.png b/html/pdf-icon-50.png
new file mode 100644
index 0000000..62873ea
--- /dev/null
+++ b/html/pdf-icon-50.png
diff --git a/html/pdf-icon.svg b/html/pdf-icon.svg
new file mode 100644
index 0000000..8b30bbb
--- /dev/null
+++ b/html/pdf-icon.svg
@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+<svg xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:cc="http://creativecommons.org/ns#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd" xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape" width="75.320129mm" height="92.604164mm" viewBox="0 0 75.320129 92.604164" version="1.1" id="svg8" inkscape:version="0.92.3 (2405546, 2018-03-11)" sodipodi:docname="PDF file icon.svg">
+  <title id="title2682">PDF file icon</title>
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+      <rect style="opacity:1;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:1;stroke-linecap:butt;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1;paint-order:fill markers stroke" id="rect841" width="68.688263" height="67.886459" x="-74.033661" y="141.44913"/>
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+  <sodipodi:namedview id="base" pagecolor="#ffffff" bordercolor="#666666" borderopacity="1.0" inkscape:pageopacity="0.0" inkscape:pageshadow="2" inkscape:zoom="0.98994949" inkscape:cx="122.12727" inkscape:cy="167.02823" inkscape:document-units="mm" inkscape:current-layer="g899" showgrid="false" inkscape:object-nodes="false" inkscape:window-width="1366" inkscape:window-height="705" inkscape:window-x="-8" inkscape:window-y="-8" inkscape:window-maximized="1" inkscape:snap-page="false" inkscape:snap-others="false" fit-margin-top="0" fit-margin-left="0" fit-margin-right="0" fit-margin-bottom="0"/>
+  <metadata id="metadata5">
+    <rdf:RDF>
+      <cc:Work rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage"/>
+        <dc:title>PDF file icon</dc:title>
+        <dc:date>08/10/2018</dc:date>
+        <dc:creator>
+          <cc:Agent>
+            <dc:title>Adobe Systems</dc:title>
+          </cc:Agent>
+        </dc:creator>
+        <dc:publisher>
+          <cc:Agent>
+            <dc:title>CMetalCore</dc:title>
+          </cc:Agent>
+        </dc:publisher>
+        <dc:description>Fuente del texto "PDF":
+Franklin Gothic Medium Cond</dc:description>
+        <cc:license rdf:resource="http://creativecommons.org/licenses/by-sa/4.0/"/>
+      </cc:Work>
+      <cc:License rdf:about="http://creativecommons.org/licenses/by-sa/4.0/">
+        <cc:permits rdf:resource="http://creativecommons.org/ns#Reproduction"/>
+        <cc:permits rdf:resource="http://creativecommons.org/ns#Distribution"/>
+        <cc:requires rdf:resource="http://creativecommons.org/ns#Notice"/>
+        <cc:requires rdf:resource="http://creativecommons.org/ns#Attribution"/>
+        <cc:permits rdf:resource="http://creativecommons.org/ns#DerivativeWorks"/>
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+          <path inkscape:connector-curvature="0" id="path845" style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:medium;line-height:125%;font-family:'Franklin Gothic Medium Cond';-inkscape-font-specification:'Franklin Gothic Medium Cond';letter-spacing:0px;word-spacing:4.26000023px;fill:#2c2c2c;fill-opacity:1;stroke:none;stroke-width:0.35824656px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1" d="m -20.930423,167.83862 h 2.364986 q 1.133514,0 1.840213,0.2169 0.706698,0.20991 1.189489,0.9446 0.482795,0.72769 0.482795,1.75625 0,0.94459 -0.391832,1.6233 -0.391833,0.67871 -1.056548,0.97958 -0.65772,0.30087 -2.02913,0.30087 h -0.818651 v 3.72941 h -1.581322 z m 1.581322,1.22447 v 3.33058 h 0.783664 q 1.049552,0 1.44838,-0.39184 0.405826,-0.39183 0.405826,-1.27345 0,-0.65772 -0.265887,-1.06355 -0.265884,-0.41282 -0.587747,-0.50378 -0.314866,-0.098 -1.000572,-0.098 z"/>
+          <path inkscape:connector-curvature="0" id="path847" style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:medium;line-height:125%;font-family:'Franklin Gothic Medium Cond';-inkscape-font-specification:'Franklin Gothic Medium Cond';letter-spacing:0px;word-spacing:4.26000023px;fill:#2c2c2c;fill-opacity:1;stroke:none;stroke-width:0.35824656px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1" d="m -13.842461,167.83862 h 2.148082 q 1.560333,0 2.4909318,0.55276 0.9375993,0.55276 1.4133973,1.6443 0.482791,1.09153 0.482791,2.42096 0,1.3994 -0.4338151,2.49793 -0.4268149,1.09153 -1.3154348,1.76324 -0.8816233,0.67172 -2.5189212,0.67172 h -2.267031 z m 1.581326,1.26645 v 7.018 h 0.657715 q 1.378411,0 2.001144,-0.9516 0.6227329,-0.95858 0.6227329,-2.5539 0,-3.5125 -2.6238769,-3.5125 z"/>
+          <path inkscape:connector-curvature="0" id="path849" style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:medium;line-height:125%;font-family:'Franklin Gothic Medium Cond';-inkscape-font-specification:'Franklin Gothic Medium Cond';letter-spacing:0px;word-spacing:4.26000023px;fill:#2c2c2c;fill-opacity:1;stroke:none;stroke-width:0.35824656px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1" d="m -5.7889096,167.83862 h 5.30372941 v 1.26645 H -4.2075842 v 2.85478 h 2.9807225 v 1.26646 h -2.9807225 v 4.16322 h -1.5813254 z"/>
+        </g>
+      </g>
+    </g>
+  </g>
+</svg>
\ No newline at end of file
diff --git a/html/stats.html b/html/stats.html
new file mode 100644
index 0000000..3f7e141
--- /dev/null
+++ b/html/stats.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<meta charset="utf-8"/>
+		<meta name="viewport" content="width=device-width, initial-scale=1">
+		<meta name="keywords" content="Reichwein, Whiteboard">
+		<title>Reichwein Whiteboard</title>
+		<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon"/>
+		<link rel="stylesheet" type="text/css" href="whiteboard.css"/>
+		<script src="stats.js"></script>
+	</head>
+	<body onload="init();">
+                <div class="qrwindow" id="qrwindow" hidden>
+			<img class="qrcode" id="qrcode"></img>
+                </div>
+		<div class="page">
+			<h1><img class="banner" src="banner256.png" alt="Reichwein.IT"/> Whiteboard</h1>
+			<h2>Statistics</h2>
+                        <table>
+                         <tr><td>Active Connections:</td><td id="numberofconnections" align="right"></td><td></td></tr>
+                         <tr><td>Number of Documents:</td><td id="numberofdocuments" align="right"></td><td></td></tr>
+                         <tr><td>Database Size (gross):</td><td id="dbsizegross" align="right"></td><td>Bytes</td></tr>
+                         <tr><td>Database Size (net):</td><td id="dbsizenet" align="right"></td><td>Bytes</td></tr>
+                        </table>
+			<br/>
+			<span id="status">Starting up...</span>
+			<button class="buttonred" id="reconnect" onclick="on_reconnect_click();" hidden>Reconnect</button>
+			<br/>
+			<br/>
+                        Reichwein.IT Whiteboard <span id="version"></span> by <a href="https://www.reichwein.it">https://www.reichwein.it</a><br/>
+		</div>
+
+		<a id="download-a" hidden></a>
+	</body>
+</html>
diff --git a/html/stats.js b/html/stats.js
new file mode 100644
index 0000000..89c674a
--- /dev/null
+++ b/html/stats.js
@@ -0,0 +1,96 @@
+// started on main page load
+function init() {
+	init_stats();
+}
+
+function set_status(message)
+{
+ if (message == "") {
+	document.getElementById("status").textContent = message;
+	document.getElementById("status").style.display = 'inline';
+ } else {
+	document.getElementById("status").textContent = "";
+	document.getElementById("status").style.display = 'none';
+ }
+}
+
+var websocket;
+
+//
+// Callbacks for websocket data of different types
+//
+
+function on_stats(numberofdocuments, numberofconnections, dbsizegross, dbsizenet)
+{
+	document.getElementById("numberofdocuments").textContent = numberofdocuments;
+	document.getElementById("numberofconnections").textContent = numberofconnections;
+	document.getElementById("dbsizegross").textContent = dbsizegross;
+	document.getElementById("dbsizenet").textContent = dbsizenet;
+}
+
+function on_version(version)
+{
+	document.getElementById("version").textContent = version;
+}
+
+function on_message(e) {
+	var parser = new DOMParser();
+	var xmlDocument = parser.parseFromString(e.data, "text/xml");
+	
+	var type = xmlDocument.getElementsByTagName("type")[0].textContent;
+
+	if (type == "stats") {
+		on_stats(xmlDocument.getElementsByTagName("numberofdocuments")[0].textContent,
+                         xmlDocument.getElementsByTagName("numberofconnections")[0].textContent,
+                         xmlDocument.getElementsByTagName("dbsizegross")[0].textContent,
+                         xmlDocument.getElementsByTagName("dbsizenet")[0].textContent);
+	} else if (type == "version") {
+		on_version(xmlDocument.getElementsByTagName("version")[0].textContent);
+	} else if (type == "error") {
+		alert(xmlDocument.getElementsByTagName("message")[0].textContent);
+	} else {
+		alert("Unhandled message type: " + e.data + "|" + type);
+	}
+}
+
+function connect_websocket() {
+	document.getElementById("reconnect").style.display = 'none';
+        set_status("Connecting...");
+	var newlocation = location.origin + location.pathname;
+	newlocation = newlocation.replace(/^http/, 'ws');
+	newlocation = newlocation.replace(/stats.html$/, '');
+	if (newlocation.slice(-1) != "/")
+		newlocation += "/";
+	newlocation += "websocket";
+
+	websocket = new WebSocket(newlocation);
+
+	websocket.onmessage = function(e) { on_message(e); };
+
+	websocket.onopen = function(e) {
+		websocket.send("<request><command>getversion</command></request>");
+		websocket.send("<request><command>getstats</command></request>");
+                set_status(""); // ok
+	};
+	
+	websocket.onclose = function(e) {
+		alert("Server connection closed.");
+		document.getElementById("reconnect").style.display = 'inline';
+	};
+
+	websocket.onerror = function(e) {
+		alert("Error: Server connection closed.");
+		document.getElementById("reconnect").style.display = 'inline';
+	};
+}
+
+// button in html
+function on_reconnect_click() {
+	connect_websocket();
+}
+
+function init_stats() {
+        set_status("Loading...");
+        connect_websocket();
+}
+
diff --git a/html/whiteboard.css b/html/whiteboard.css
new file mode 100644
index 0000000..2d222d5
--- /dev/null
+++ b/html/whiteboard.css
@@ -0,0 +1,150 @@
+body {
+	font-family: sans-serif;
+}
+
+figcaption {
+	text-align: center;
+	font-size: 8px;
+	color: #808080;
+}
+
+figure {
+	display: inline-block;
+}
+
+p {
+	margin: 30px 0px 30px 0px;
+}
+
+div.status {
+	color: #FF0000;
+}
+
+span.helper {
+	display: inline-block;
+	height: 100%;
+	vertical-align: middle;
+}
+
+img.center-img {
+	vertical-align: middle;
+}
+
+.clickable {
+	cursor: pointer;
+}
+
+textarea {
+	/*
+	height: 30vh;
+	padding: 1em;
+	font-size: 1.5em;
+	text-align: left;
+	border: 1px solid #000;
+	*/
+	box-sizing: border-box;
+	resize: none;
+
+	width: 100%;
+	height: 540px;
+}
+
+.qrwindow {
+        position: fixed;
+        top: 50%;
+        left: 50%;
+        width: 400px;
+        height: 400px;
+        margin-top: -200px;
+        margin-left: -200px;
+        background-color: #FFFFFF;
+        opacity: 1;
+        z-index: 10;
+        border-width: 3px;
+        border-style: solid;
+        border-color: #FFFFFF;
+        padding: 10pt;
+        box-sizing: border-box;
+}
+
+.qrcode {
+        width: 374px;
+        height: 374px;
+    
+        image-rendering: optimizeSpeed;             /*                     */
+        image-rendering: -moz-crisp-edges;          /* Firefox             */
+        image-rendering: -o-crisp-edges;            /* Opera               */
+        image-rendering: -webkit-optimize-contrast; /* Chrome (and Safari) */
+        image-rendering: pixelated;                 /* Chrome as of 2019   */
+        image-rendering: optimize-contrast;         /* CSS3 Proposed       */
+        -ms-interpolation-mode: nearest-neighbor;   /* IE8+                */
+}
+
+.mobile {
+	width: 300px;
+	border-width: 80px 15px 80px 15px;
+       	border-style: solid;
+	border-radius: 30px;
+	border-color: #000000;
+}
+
+.logo {
+	display: block;
+	margin: 0 auto;
+}
+
+.screenshot {
+	width: 400px;
+	border: 2px solid;
+	border-color: #8888AA;
+}
+
+img.banner {
+	vertical-align: -5px;
+}
+
+.button {
+        color:#FFFFFF;
+        background-color:#50B050;
+        text-decoration: none;
+        padding: 15px 20px;
+        font-size: 16px;
+        border: none;
+        border-radius: 6px;
+	cursor: pointer;
+}
+
+.buttonred {
+        color:#FFFFFF;
+        background-color:#B05050;
+        text-decoration: none;
+        padding: 15px 20px;
+        font-size: 16px;
+        border: none;
+        border-radius: 6px;
+	cursor: pointer;
+}
+
+@media only screen and (min-width: 1px) and (max-width: 630px) {
+
+.qrwindow {
+        position: fixed;
+        top: 0;
+        left: 0;
+        width: 100%;
+        height: 100%;
+        margin: 0;
+}
+
+}
+
+@media only screen and (min-width: 631px) and (max-width: 950px) {
+}
+
+@media only screen and (min-width: 951px) {
+	div.page {
+		max-width: 950px;
+		width: 100%;
+		margin: 0 auto;
+	}
+}
diff --git a/html/whiteboard.js b/html/whiteboard.js
new file mode 100644
index 0000000..379c757
--- /dev/null
+++ b/html/whiteboard.js
@@ -0,0 +1,351 @@
+// started on main page load
+function init() {
+	init_board();
+}
+
+var revision;
+var modify_in_progress = 0;
+var baseline = ""; // data contents relating to revision, acknowledged by server
+var baseline_candidate = ""; // will become baseline, after ack by server
+
+// helper for breaking feedback loop
+var caretpos = 0;
+
+function set_status(message)
+{
+ if (message == "") {
+	document.getElementById("status").textContent = message;
+	document.getElementById("status").style.display = 'inline';
+ } else {
+	document.getElementById("status").textContent = "";
+	document.getElementById("status").style.display = 'none';
+ }
+}
+
+function showQRWindow()
+{
+ document.getElementById("qrwindow").style.display = 'block';
+}
+
+function hideQRWindow()
+{
+ document.getElementById("qrwindow").style.display = 'none';
+}
+
+var websocket;
+
+//
+// Callbacks for websocket data of different types
+//
+
+function on_getfile(data, rev, pos)
+{
+	var board = document.getElementById("board");
+	if (board.value != data) {
+		board.value = data;
+	}
+	revision = rev;
+        baseline = data;
+	textAreaSetPos("board", pos);
+}
+
+function on_getdiff(diff, rev, pos)
+{
+        if (rev != revision + 1)
+         console.log("Revision skipped on diff receive: " + rev + " after " + revision);
+
+	var board = document.getElementById("board");
+
+        var old_version_ptr = allocateUTF8(board.value);
+        var diff_ptr = allocateUTF8(new XMLSerializer().serializeToString(diff));
+        var new_version_ptr = Module._diff_apply(old_version_ptr, diff_ptr);
+        var data = UTF8ToString(new_version_ptr);
+	board.value = data;
+        _free(old_version_ptr);
+        _free(new_version_ptr);
+        _free(diff_ptr);
+
+	revision = rev;
+        baseline = data;
+	textAreaSetPos("board", pos);
+}
+
+function on_getpos(pos)
+{
+	textAreaSetPos("board", pos);
+}
+
+function on_newid(id)
+{
+	var new_location = document.location.origin + document.location.pathname + '?id=' + id;
+	window.location.href = new_location;
+}
+
+function on_qrcode(png)
+{
+	var url = "data:image/png;base64," + png;
+	var img = document.getElementById("qrcode");
+	img.src = url;
+	showQRWindow();
+}
+
+function on_version(version)
+{
+	document.getElementById("version").textContent = version;
+}
+
+function on_pdf(pdf)
+{
+        var a = document.getElementById("download-a");
+        a.href = "data:application/pdf;base64," + pdf;
+        a.download = get_id() + ".pdf"
+        a.click();
+}
+
+function on_modify_ack(rev)
+{
+        if (rev != revision + 1)
+         console.log("Revision skipped on published local change: " + rev + " after " + revision);
+
+	revision = rev;
+        baseline = baseline_candidate;
+        modify_in_progress = 0;
+}
+
+function on_message(e) {
+	var parser = new DOMParser();
+	var xmlDocument = parser.parseFromString(e.data, "text/xml");
+	
+	var type = xmlDocument.getElementsByTagName("type")[0].textContent;
+
+	if (type == "getfile") {
+		on_getfile(xmlDocument.getElementsByTagName("data")[0].textContent,
+			   parseInt(xmlDocument.getElementsByTagName("revision")[0].textContent),
+		           parseInt(xmlDocument.getElementsByTagName("pos")[0].textContent));
+        } else if (type == "getdiff") {
+		on_getdiff(xmlDocument.getElementsByTagName("diff")[0],
+			   parseInt(xmlDocument.getElementsByTagName("revision")[0].textContent),
+                           parseInt(xmlDocument.getElementsByTagName("pos")[0].textContent));
+	} else if (type == "getpos") {
+		on_getpos(parseInt(xmlDocument.getElementsByTagName("pos")[0].textContent));
+	} else if (type == "modify") {
+		on_modify_ack(parseInt(xmlDocument.getElementsByTagName("revision")[0].textContent));
+	} else if (type == "newid") {
+		on_newid(xmlDocument.getElementsByTagName("id")[0].textContent);
+	} else if (type == "qrcode") {
+		on_qrcode(xmlDocument.getElementsByTagName("png")[0].textContent);
+	} else if (type == "version") {
+		on_version(xmlDocument.getElementsByTagName("version")[0].textContent);
+	} else if (type == "pdf") {
+		on_pdf(xmlDocument.getElementsByTagName("pdf")[0].textContent);
+	} else if (type == "error") {
+		alert(xmlDocument.getElementsByTagName("message")[0].textContent);
+	} else {
+		alert("Unhandled message type: " + e.data + "|" + type);
+	}
+}
+
+function handleSelection() {
+  const activeElement = document.activeElement
+
+  if (activeElement && activeElement.id === 'board') {
+    if (caretpos != activeElement.selectionStart) {
+      on_selectionchange(activeElement.selectionStart);
+      caretpos = activeElement.selectionStart;
+    }
+  }
+}
+
+function connect_websocket() {
+	document.getElementById("reconnect").style.display = 'none';
+        set_status("Connecting...");
+	var newlocation = location.origin + location.pathname;
+	newlocation = newlocation.replace(/^http/, 'ws');
+	if (newlocation.slice(-1) != "/")
+		newlocation += "/";
+	newlocation += "websocket";
+
+	websocket = new WebSocket(newlocation);
+
+	websocket.onmessage = function(e) { on_message(e); };
+
+	websocket.onopen = function(e) {
+		const searchParams = (new URL(document.location)).searchParams;
+		if (!searchParams.has('id')) {
+			redirect_to_new_page();
+			return;
+		}
+
+		websocket.send("<request><command>getversion</command></request>");
+		websocket.send("<request><command>getfile</command><id>" + get_id() + "</id></request>");
+                set_status(""); // ok
+	        document.getElementById("board").focus();
+	};
+	
+	websocket.onclose = function(e) {
+		alert("Server connection closed.");
+		document.getElementById("reconnect").style.display = 'inline';
+	        document.getElementById("reconnect").focus();
+	};
+
+	websocket.onerror = function(e) {
+		alert("Error: Server connection closed.");
+		document.getElementById("reconnect").style.display = 'inline';
+	        document.getElementById("reconnect").focus();
+	};
+}
+
+// button in html
+function on_reconnect_click() {
+	connect_websocket();
+}
+
+function init_board() {
+        set_status("Loading...");
+	Module.onRuntimeInitialized = () => {
+         connect_websocket();
+        };
+	
+	var board = document.getElementById("board");
+	board.addEventListener("input", function() {on_input(); });
+	// Need this workaround (different from direct on_selectionchange) for Chrome.
+	// Otherwise, callback will not be called on Chrome.
+	document.addEventListener("selectionchange", handleSelection);
+	//board.addEventListener("selectionchange", function() {on_selectionchange(); });
+
+        document.getElementById("qrwindow").onclick = function() {
+         hideQRWindow();
+        }
+
+        document.onkeydown = function(evt) {
+         if (evt.key == "Escape") {
+          hideQRWindow();
+         }
+        }
+
+	document.getElementById("board").focus();
+}
+
+function get_id()
+{
+        const searchParams = (new URL(document.location)).searchParams;
+        return searchParams.get('id');
+}
+
+// from html
+function on_new_page()
+{
+	redirect_to_new_page();
+}
+
+function redirect_to_new_page()
+{
+	websocket.send("<request><command>newid</command></request>");
+}
+
+// local change done
+function on_input()
+{
+        if (modify_in_progress == 1) {
+                console.log("Deferring on_input handler by 100ms");
+                setTimeout(function(){on_input();}, 100); // re-try after 100ms
+                return;
+        }
+        modify_in_progress = 1;
+
+	var parser = new DOMParser();
+	var xmlDocument = parser.parseFromString("<request></request>", "text/xml");
+	
+	var requestElement = xmlDocument.getElementsByTagName("request")[0];
+
+	var commandElement = xmlDocument.createElement("command");
+	commandElement.appendChild(document.createTextNode("modify"));
+	requestElement.appendChild(commandElement);
+
+	var idElement = xmlDocument.createElement("id");
+	idElement.appendChild(document.createTextNode(get_id()));
+	requestElement.appendChild(idElement);
+
+        baseline_candidate = document.getElementById("board").value;
+
+        if (baseline == baseline_candidate) {
+         modify_in_progress = 0;
+         return;
+        }
+
+	var revisionElement = xmlDocument.createElement("baserev");
+	revisionElement.appendChild(document.createTextNode(revision));
+	requestElement.appendChild(revisionElement);
+	
+        var old_version = allocateUTF8(baseline);
+        var new_version = allocateUTF8(baseline_candidate);
+        var diff = Module._diff_create(old_version, new_version);
+        var diffDocument = parser.parseFromString(UTF8ToString(diff), "text/xml");
+        _free(old_version);
+        _free(new_version);
+        _free(diff);
+	requestElement.appendChild(xmlDocument.importNode(diffDocument.getElementsByTagName("diff")[0], true));
+	
+        var posElement = xmlDocument.createElement("pos");
+	posElement.appendChild(document.createTextNode(document.getElementById("board").selectionStart));
+	requestElement.appendChild(posElement);
+
+	websocket.send(new XMLSerializer().serializeToString(xmlDocument));
+}
+
+// for cursor position
+function on_selectionchange(pos)
+{
+	var parser = new DOMParser();
+	var xmlDocument = parser.parseFromString("<request></request>", "text/xml");
+	
+	var requestElement = xmlDocument.getElementsByTagName("request")[0];
+
+	var commandElement = xmlDocument.createElement("command");
+	commandElement.appendChild(document.createTextNode("cursorpos"));
+	requestElement.appendChild(commandElement);
+
+	var idElement = xmlDocument.createElement("id");
+	idElement.appendChild(document.createTextNode(get_id()));
+	requestElement.appendChild(idElement);
+
+	var posElement = xmlDocument.createElement("pos");
+	posElement.appendChild(document.createTextNode(pos));
+	requestElement.appendChild(posElement);
+
+	websocket.send(new XMLSerializer().serializeToString(xmlDocument));
+}
+
+function textAreaSetPos(id, pos)
+{
+	if (document.getElementById(id).selectionStart != pos) {
+		document.getElementById(id).selectionStart = pos;
+		document.getElementById(id).selectionEnd = pos;
+		caretpos = pos;
+	}
+}
+
+// HTML button
+function on_qrcode_click()
+{
+	var parser = new DOMParser();
+	var xmlDocument = parser.parseFromString("<request></request>", "text/xml");
+	
+	var requestElement = xmlDocument.getElementsByTagName("request")[0];
+
+	var commandElement = xmlDocument.createElement("command");
+	commandElement.appendChild(document.createTextNode("qrcode"));
+	requestElement.appendChild(commandElement);
+
+	var idElement = xmlDocument.createElement("url");
+	idElement.appendChild(document.createTextNode(document.location));
+	requestElement.appendChild(idElement);
+
+	websocket.send(new XMLSerializer().serializeToString(xmlDocument));
+}
+
+function on_pdf_click()
+{
+	websocket.send("<request><command>pdf</command><id>" + get_id() + "</id></request>");
+}
+
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..e1c1cf1
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,8 @@
+#include "whiteboard.h"
+
+int main(int argc, char* argv[])
+{
+ Whiteboard whiteboard;
+ return whiteboard.run(argc, argv);
+}
+
diff --git a/qrcode.cpp b/qrcode.cpp
new file mode 100644
index 0000000..da747a5
--- /dev/null
+++ b/qrcode.cpp
@@ -0,0 +1,37 @@
+#include "qrcode.h"
+
+#include <fmt/format.h>
+
+#include <qrcodegen/QrCode.hpp>
+
+#include <Magick++.h>
+
+using namespace qrcodegen;
+using namespace Magick;
+
+void QRCode::init()
+{
+ Magick::InitializeMagick(NULL);
+}
+
+std::string QRCode::getQRCode(const std::string& data)
+{
+ QrCode qrc {QrCode::encodeText(data.c_str(), QrCode::Ecc::MEDIUM)};
+
+ int size {qrc.getSize()};
+
+ Image image(fmt::format("{0}x{0}", size).c_str(), "white");
+ image.type(GrayscaleType);
+
+ for (int x = 0; x < size; x++) {
+  for (int y = 0; y < size; y++) {
+   image.pixelColor(x, y, qrc.getModule(x, y) ? "black" : "white");
+  }
+ }
+
+ image.magick("PNG");
+
+ Blob blob;
+ image.write(&blob);
+ return std::string{(char*)blob.data(), blob.length()};
+}
diff --git a/qrcode.h b/qrcode.h
new file mode 100644
index 0000000..f37c318
--- /dev/null
+++ b/qrcode.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <string>
+
+namespace QRCode
+{
+ void init();
+
+ // returns PNG file contents
+ std::string getQRCode(const std::string& data);
+}
diff --git a/remote-install.sh b/remote-install.sh
new file mode 100755
index 0000000..6683d2e
--- /dev/null
+++ b/remote-install.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+#
+# Script to be run on target server to install *.deb and *.tgz
+#
+
+set -e
+
+if [ "$#" != "2" ] ; then
+	echo "Usage: remote-install.sh <ProjectName> <Version>"
+	exit 0
+fi
+
+PROJECTNAME=$1
+VERSION=$2
+DISTROS="debian11"
+
+cd /var/www/reichwein.it-debian
+
+for i in $DISTROS; do
+  echo "Installing ${PROJECTNAME} for $i ..."
+  reprepro -C $i --ignore=wrongdistribution include stable /home/rr/result/$i/${PROJECTNAME}_${VERSION}_amd64.changes
+  echo "Copying ${PROJECTNAME} for $i to direct download location ..."
+  #cp /home/rr/result/$i/${PROJECTNAME}_${VERSION}_*.deb /var/www/reichwein.it-download/$i/
+done
diff --git a/storage.cpp b/storage.cpp
new file mode 100644
index 0000000..92f274f
--- /dev/null
+++ b/storage.cpp
@@ -0,0 +1,235 @@
+#include "storage.h"
+
+#include "config.h"
+
+#include <chrono>
+#include <iostream>
+#include <random>
+
+#include <SQLiteCpp/SQLiteCpp.h>
+
+using namespace std::string_literals;
+
+Storage::Storage(const Config& config):
+ m_db(config.getDataPath() + "/whiteboard.db3", SQLite::OPEN_READWRITE | SQLite::OPEN_CREATE),
+ m_maxage(config.getMaxage()),
+
+ // Note about VARCHAR(N): "SQLite does not impose any length restrictions" - handled elsewhere in application
+ m_stmt_create(m_db, "CREATE TABLE IF NOT EXISTS documents (id VARCHAR(16) PRIMARY KEY, value BLOB, rev INTEGER, cursorpos INTEGER, timestamp BIGINT)"),
+ m_stmt_getNumberOfDocuments(m_db, "SELECT COUNT(*) FROM documents"),
+ m_stmt_cleanup(m_db, "DELETE FROM documents WHERE timestamp + ? < ?"),
+ m_stmt_vacuum(m_db, "VACUUM"),
+ m_stmt_exists(m_db, "SELECT id FROM documents WHERE id = ?"),
+ m_stmt_getDocument(m_db, "SELECT value FROM documents WHERE id = ?"),
+ m_stmt_getRevision(m_db, "SELECT rev FROM documents WHERE id = ?"),
+ m_stmt_getCursorPos(m_db, "SELECT cursorpos FROM documents WHERE id = ?"),
+ m_stmt_getRow(m_db, "SELECT value, rev, cursorpos FROM documents WHERE id = ?"),
+ m_stmt_setDocument(m_db, "UPDATE documents SET value = ?, timestamp = ?, rev = rev + 1 WHERE id = ?"),
+ m_stmt_setDocument_new(m_db, "INSERT INTO documents (id, value, rev, cursorpos, timestamp) values (?, ?, ?, ?, ?)"),
+ m_stmt_setRevision(m_db, "UPDATE documents SET rev = ? WHERE id = ?"),
+ m_stmt_setCursorPos(m_db, "UPDATE documents SET cursorpos = ? WHERE id = ?"),
+ m_stmt_setRow(m_db, "INSERT OR REPLACE INTO documents (id, value, rev, cursorpos, timestamp) values (?, ?, ?, ?, ?)"),
+ m_stmt_getDbSizeGross(m_db, "SELECT page_count * page_size as size FROM pragma_page_count(), pragma_page_size()"),
+ m_stmt_getDbSizeNet(m_db, "SELECT (page_count - freelist_count) * page_size as size FROM pragma_page_count(), pragma_freelist_count(), pragma_page_size()"),
+ m_stmt_touchDocument(m_db, "UPDATE documents SET timestamp = ? WHERE id = ?")
+{
+ CompiledSQL::Guard g{m_stmt_create};
+ m_stmt_create.execute();
+}
+
+Storage::~Storage()
+{
+}
+
+uint64_t Storage::getNumberOfDocuments()
+{
+ CompiledSQL::Guard g{m_stmt_getNumberOfDocuments};
+ if (!m_stmt_getNumberOfDocuments.execute())
+  throw std::runtime_error("Count not possible");
+ 
+ return m_stmt_getNumberOfDocuments.getColumn<int64_t>(0);
+}
+
+uint64_t Storage::dbsize_gross()
+{
+ CompiledSQL::Guard g{m_stmt_getDbSizeGross};
+ if (!m_stmt_getDbSizeGross.execute())
+  throw std::runtime_error("DB size count (gross) not possible");
+ 
+ return m_stmt_getDbSizeGross.getColumn<int64_t>(0);
+}
+
+uint64_t Storage::dbsize_net()
+{
+ CompiledSQL::Guard g{m_stmt_getDbSizeNet};
+ if (!m_stmt_getDbSizeNet.execute())
+  throw std::runtime_error("DB size count (net) not possible");
+ 
+ return m_stmt_getDbSizeNet.getColumn<int64_t>(0);
+}
+
+namespace {
+ uint64_t unixepoch()
+ {
+  const auto p1 = std::chrono::system_clock::now();
+  return std::chrono::duration_cast<std::chrono::seconds>(p1.time_since_epoch()).count();
+ }
+} // namespace
+
+void Storage::cleanup()
+{
+ if (m_maxage != 0) {
+  CompiledSQL::Guard g{m_stmt_cleanup};
+  m_stmt_cleanup.bind(1, static_cast<int64_t>(m_maxage));
+  m_stmt_cleanup.bind(2, static_cast<int64_t>(unixepoch()));
+  m_stmt_cleanup.execute();
+ }
+ 
+ CompiledSQL::Guard g{m_stmt_vacuum};
+ m_stmt_vacuum.execute();
+}
+
+bool Storage::exists(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_exists};
+ m_stmt_exists.bind(1, id);
+
+ return m_stmt_exists.execute();
+}
+
+std::string Storage::getDocument(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_getDocument};
+ m_stmt_getDocument.bind(1, id);
+
+ if (!m_stmt_getDocument.execute())
+  throw std::runtime_error("id "s + id + " not found"s);
+
+ return m_stmt_getDocument.getColumn<std::string>(0);
+}
+
+int Storage::getRevision(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_getRevision};
+ m_stmt_getRevision.bind(1, id);
+
+ if (!m_stmt_getRevision.execute())
+  throw std::runtime_error("id "s + id + " not found"s);
+
+ return m_stmt_getRevision.getColumn<int>(0);
+}
+
+int Storage::getCursorPos(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_getCursorPos};
+ m_stmt_getCursorPos.bind(1, id);
+
+ if (!m_stmt_getCursorPos.execute())
+  throw std::runtime_error("id "s + id + " not found"s);
+
+ return m_stmt_getCursorPos.getColumn<int>(0);
+}
+
+std::tuple<std::string, int, int> Storage::getRow(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_getRow};
+ m_stmt_getRow.bind(1, id);
+
+ if (!m_stmt_getRow.execute())
+  throw std::runtime_error("id "s + id + " not found"s);
+
+ return {m_stmt_getRow.getColumn<std::string>(0), m_stmt_getRow.getColumn<int>(1), m_stmt_getRow.getColumn<int>(2)};
+}
+ 
+void Storage::setDocument(const std::string& id, const std::string& document)
+{
+ CompiledSQL::Guard g{m_stmt_setDocument};
+ m_stmt_setDocument.bind(1, document);
+ m_stmt_setDocument.bind(2, static_cast<int64_t>(unixepoch()));
+ m_stmt_setDocument.bind(3, id);
+
+ if (!m_stmt_setDocument.execute()) {
+  CompiledSQL::Guard g{m_stmt_setDocument_new};
+  m_stmt_setDocument_new.bind(1, id);
+  m_stmt_setDocument_new.bind(2, document);
+  m_stmt_setDocument_new.bind(3, 0);
+  m_stmt_setDocument_new.bind(4, 0);
+  m_stmt_setDocument_new.bind(5, static_cast<int64_t>(unixepoch()));
+  if (!m_stmt_setDocument_new.execute())
+   throw std::runtime_error("Unable to create document with id "s + id);
+ }
+}
+
+void Storage::setRevision(const std::string& id, int rev)
+{
+ CompiledSQL::Guard g{m_stmt_setRevision};
+ m_stmt_setRevision.bind(1, rev);
+ m_stmt_setRevision.bind(2, id);
+
+ if (!m_stmt_setRevision.execute())
+  throw std::runtime_error("Unable to set revision for id "s + id);
+}
+
+void Storage::setCursorPos(const std::string& id, int cursorPos)
+{
+ CompiledSQL::Guard g{m_stmt_setCursorPos};
+ m_stmt_setCursorPos.bind(1, cursorPos);
+ m_stmt_setCursorPos.bind(2, id);
+
+ if (!m_stmt_setCursorPos.execute())
+  throw std::runtime_error("Unable to set cursor position for id "s + id);
+}
+
+void Storage::setRow(const std::string& id, const std::string& document, int rev, int cursorPos)
+{
+ CompiledSQL::Guard g{m_stmt_setRow};
+ m_stmt_setRow.bind(1, id);
+ m_stmt_setRow.bind(2, document);
+ m_stmt_setRow.bind(3, rev);
+ m_stmt_setRow.bind(4, cursorPos);
+ m_stmt_setRow.bind(5, static_cast<int64_t>(unixepoch()));
+ if (!m_stmt_setRow.execute())
+  throw std::runtime_error("Unable to insert row with id "s + id);
+}
+
+uint32_t checksum32(const std::string& s)
+{
+ uint32_t result{0};
+ for (unsigned int i = 0; i < s.size(); i++) {
+  result = ((result >> 1) | ((result & 1) << 31)) ^ (s[i] & 0xFF);
+ }
+ return result & 0x7FFFFFFF;
+}
+
+std::string Storage::generate_id()
+{
+ static std::random_device r;
+ static std::default_random_engine e1(r());
+ static std::uniform_int_distribution<int> uniform_dist(0, 35);
+
+ // limit tries
+ for (int j = 0; j < 100000; j++) {
+  std::string result;
+  for (int i = 0; i < 6; i++) {
+   char c{static_cast<char>('0' + uniform_dist(e1))};
+   if (c > '9')
+    c = c - '9' - 1 + 'a';
+   result.push_back(c);
+  }
+
+  if (!exists(result))
+   return result;
+ }
+
+ return "endofcodes";
+}
+
+void Storage::touchDocument(const std::string& id)
+{
+ CompiledSQL::Guard g{m_stmt_touchDocument};
+ m_stmt_touchDocument.bind(1, static_cast<int64_t>(unixepoch()));
+ m_stmt_touchDocument.bind(2, id);
+ if (!m_stmt_touchDocument.execute())
+  throw std::runtime_error("Unable to touch document with id "s + id);
+}
+
diff --git a/storage.h b/storage.h
new file mode 100644
index 0000000..131b786
--- /dev/null
+++ b/storage.h
@@ -0,0 +1,64 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <tuple>
+
+#include <SQLiteCpp/SQLiteCpp.h>
+
+#include "config.h"
+#include "compiledsql.h"
+
+class Storage
+{
+public:
+ Storage(const Config& config);
+ ~Storage();
+
+ uint64_t getNumberOfDocuments();
+ uint64_t dbsize_gross();
+ uint64_t dbsize_net();
+ bool exists(const std::string& id);
+
+ std::string getDocument(const std::string& id);
+ int getRevision(const std::string& id);
+ int getCursorPos(const std::string& id);
+ std::tuple<std::string, int, int> getRow(const std::string& id);
+ 
+ void setDocument(const std::string& id, const std::string& document);
+ void setRevision(const std::string& id, int rev);
+ void setCursorPos(const std::string& id, int cursorPos);
+ void setRow(const std::string& id, const std::string& document, int rev, int cursorPos);
+
+ void touchDocument(const std::string& id);
+ 
+ void cleanup();
+
+ std::string generate_id();
+
+private:
+ SQLite::Database m_db;
+ uint64_t m_maxage;
+
+ // shared_ptr to work around initialization in constructor
+ CompiledSQL m_stmt_create;
+ CompiledSQL m_stmt_getNumberOfDocuments;
+ CompiledSQL m_stmt_cleanup;
+ CompiledSQL m_stmt_vacuum;
+ CompiledSQL m_stmt_exists;
+ CompiledSQL m_stmt_getDocument;
+ CompiledSQL m_stmt_getRevision;
+ CompiledSQL m_stmt_getCursorPos;
+ CompiledSQL m_stmt_getRow;
+ CompiledSQL m_stmt_setDocument;
+ CompiledSQL m_stmt_setDocument_new;
+ CompiledSQL m_stmt_setRevision;
+ CompiledSQL m_stmt_setCursorPos;
+ CompiledSQL m_stmt_setRow;
+ CompiledSQL m_stmt_getDbSizeGross;
+ CompiledSQL m_stmt_getDbSizeNet;
+ CompiledSQL m_stmt_touchDocument;
+};
+
+uint32_t checksum32(const std::string& s);
+
diff --git a/tests/Makefile b/tests/Makefile
new file mode 100644
index 0000000..f3ec6c8
--- /dev/null
+++ b/tests/Makefile
@@ -0,0 +1,79 @@
+CXXFLAGS=-g -O0
+
+include ../common.mk
+
+ifeq ($(CXXTYPE),clang++)
+CXXFLAGS+=-fprofile-instr-generate -fcoverage-mapping
+LDFLAGS+=-fprofile-instr-generate -fcoverage-mapping
+else
+# GCC
+CXXFLAGS+=--coverage
+LDFLAGS+=--coverage
+endif
+
+UNITS=storage.cpp config.cpp compiledsql.cpp qrcode.cpp whiteboard.cpp connectionregistry.cpp diff.cpp
+
+UNITTESTS=test-config.cpp \
+	  test-storage.cpp \
+	  test-connectionregistry.cpp \
+	  test-compiledsql.cpp \
+	  test-qrcode.cpp \
+	  test-whiteboard.cpp \
+	  test-diff.cpp
+
+CXXFLAGS+=\
+         -I/usr/src/googletest/googletest/include \
+         -I/usr/src/googletest/googlemock/include \
+         -I/usr/src/googletest/googletest \
+         -I/usr/src/googletest/googlemock \
+         -I..
+
+test: unittests
+	# https://clang.llvm.org/docs/SourceBasedCodeCoverage.html
+ifeq ($(CXXTYPE),clang++)
+	LLVM_PROFILE_FILE="unittests.profraw" ./unittests
+	$(LLVMPROFDATA) merge -sparse unittests.profraw -o unittests.profdata
+	$(LLVMCOV) report --ignore-filename-regex='google' --ignore-filename-regex='test-' --ignore-filename-regex='Magick' --show-region-summary=0 -instr-profile unittests.profdata unittests
+else
+	./unittests
+	gcovr -r ..
+endif
+
+coverage:
+	$(LLVMCOV) show -instr-profile unittests.profdata $(UNITS:.cpp=.o)
+
+unittests: libgmock.a $(UNITTESTS:.cpp=.o) $(UNITS:.cpp=.o)
+	$(CXX) $(LDFLAGS) $^ $(LDLIBS) $(LIBS) -o $@
+
+%.o: %.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+config.o: ../config.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+connectionregistry.o: ../connectionregistry.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+diff.o: ../diff.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+storage.o: ../storage.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+compiledsql.o: ../compiledsql.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+whiteboard.o: ../whiteboard.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+qrcode.o: ../qrcode.cpp
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+libgmock.a:
+	$(CXX) $(CXXFLAGS) -c /usr/src/googletest/googletest/src/gtest-all.cc
+	$(CXX) $(CXXFLAGS) -c /usr/src/googletest/googlemock/src/gmock-all.cc
+	$(CXX) $(CXXFLAGS) -c /usr/src/googletest/googlemock/src/gmock_main.cc
+	ar -rv libgmock.a gmock-all.o gtest-all.o gmock_main.o
+
+clean:
+	-rm -f *.o *.a unittests *.gcda *.gcno *.profraw *.profdata *.gcov
diff --git a/tests/test-compiledsql.cpp b/tests/test-compiledsql.cpp
new file mode 100644
index 0000000..d14220c
--- /dev/null
+++ b/tests/test-compiledsql.cpp
@@ -0,0 +1,77 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <system_error>
+
+#include "libreichwein/file.h"
+
+#include "config.h"
+#include "storage.h"
+#include "whiteboard.h"
+
+namespace fs = std::filesystem;
+
+namespace {
+ const std::string testDbFilename{"./whiteboard.db3"};
+}
+
+class CompiledSQLTest: public ::testing::Test
+{
+protected:
+ CompiledSQLTest(){
+ }
+
+ ~CompiledSQLTest() override{
+ }
+
+ void SetUp() override
+ {
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+ }
+
+ void TearDown() override
+ {
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+ }
+
+};
+
+TEST_F(CompiledSQLTest, create)
+{
+ SQLite::Database db{testDbFilename, SQLite::OPEN_READWRITE | SQLite::OPEN_CREATE};
+
+ {
+  CompiledSQL stmt1{db, "CREATE TABLE documents (id VARCHAR(16) PRIMARY KEY)"};
+  CompiledSQL::Guard g{stmt1};
+  stmt1.execute();
+ }
+
+ {
+  CompiledSQL stmt2{db, "INSERT INTO documents (id) values (?)"};
+  CompiledSQL::Guard g{stmt2};
+  stmt2.bind(1, "abc");
+  ASSERT_TRUE(stmt2.execute());
+ }
+
+ {
+  CompiledSQL stmt3{db, "SELECT id FROM documents WHERE id = ?"};
+  CompiledSQL::Guard g{stmt3};
+  stmt3.bind(1, "abc");
+  ASSERT_TRUE(stmt3.execute());
+  EXPECT_EQ(stmt3.getColumn<std::string>(0), "abc");
+ }
+
+ {
+  CompiledSQL stmt4{db, "SELECT id FROM documents WHERE id = ?"};
+  CompiledSQL::Guard g{stmt4};
+  stmt4.bind(1, "def");
+  ASSERT_FALSE(stmt4.execute());
+ }
+
+ EXPECT_TRUE(fs::exists(testDbFilename));
+}
+
diff --git a/tests/test-config.cpp b/tests/test-config.cpp
new file mode 100644
index 0000000..816dfea
--- /dev/null
+++ b/tests/test-config.cpp
@@ -0,0 +1,63 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <string>
+#include <system_error>
+
+#include "libreichwein/file.h"
+
+#include "config.h"
+
+namespace fs = std::filesystem;
+using namespace Reichwein;
+
+namespace {
+ const std::string testConfigFilename{"./test.conf"};
+ const std::string testDbFilename{"./whiteboard.db3"};
+}
+
+class ConfigTest: public ::testing::Test
+{
+protected:
+ ConfigTest(){
+ }
+
+ ~ConfigTest(){
+ }
+};
+
+TEST_F(ConfigTest, defaultData)
+{
+ std::string filename{testConfigFilename + "doesntexist"};
+ std::error_code ec;
+ fs::remove(filename, ec);
+ ASSERT_TRUE(!fs::exists(filename));
+ {
+  Config config{filename};
+  EXPECT_EQ(config.getDataPath(), "/var/lib/whiteboard");
+  EXPECT_EQ(config.getMaxage(), 0UL);
+  ASSERT_TRUE(!fs::exists(filename));
+ }
+ 
+ ASSERT_TRUE(!fs::exists(filename));
+}
+
+TEST_F(ConfigTest, testData)
+{
+ File::setFile(testConfigFilename, R"CONFIG(
+<config>
+ <datapath>/some/other/location</datapath>
+ <maxage>2592000</maxage>
+</config>
+)CONFIG");
+
+ {
+  Config config{testConfigFilename};
+  EXPECT_EQ(config.getDataPath(), "/some/other/location");
+  EXPECT_EQ(config.getMaxage(), 2592000UL);
+ }
+
+ std::error_code ec;
+ fs::remove(testConfigFilename, ec);
+}
+
diff --git a/tests/test-connectionregistry.cpp b/tests/test-connectionregistry.cpp
new file mode 100644
index 0000000..dbc2b7e
--- /dev/null
+++ b/tests/test-connectionregistry.cpp
@@ -0,0 +1,170 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <string>
+#include <system_error>
+
+#include <boost/beast/core.hpp>
+#include <boost/beast/http.hpp>
+
+#include "libreichwein/file.h"
+
+#include "connectionregistry.h"
+
+namespace fs = std::filesystem;
+using namespace Reichwein;
+
+class ConnectionRegistryTest: public ::testing::Test
+{
+protected:
+ ConnectionRegistryTest(){
+ }
+
+ ~ConnectionRegistryTest(){
+ }
+};
+
+TEST_F(ConnectionRegistryTest, constructor)
+{
+ ConnectionRegistry cr{};
+}
+
+TEST_F(ConnectionRegistryTest, test_addConnection)
+{
+ boost::asio::io_context ioc{1};
+
+ boost::asio::ip::tcp::socket ts0{ioc};
+ ConnectionRegistry::connection c0 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts0))};
+ 
+ boost::asio::ip::tcp::socket ts1{ioc};
+ ConnectionRegistry::connection c1 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts1))};
+ 
+ ConnectionRegistry cr{};
+
+ cr.addConnection(c0);
+ EXPECT_THROW(cr.addConnection(c0), std::exception);
+ cr.addConnection(c1);
+ EXPECT_THROW(cr.addConnection(c0), std::exception);
+ EXPECT_THROW(cr.addConnection(c1), std::exception);
+}
+
+TEST_F(ConnectionRegistryTest, test_delConnection)
+{
+ boost::asio::io_context ioc{1};
+
+ boost::asio::ip::tcp::socket ts0{ioc};
+ ConnectionRegistry::connection c0 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts0))};
+ 
+ boost::asio::ip::tcp::socket ts1{ioc};
+ ConnectionRegistry::connection c1 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts1))};
+ 
+ ConnectionRegistry cr{};
+
+ EXPECT_THROW(cr.delConnection(c0), std::exception);
+ 
+ cr.addConnection(c0);
+ cr.delConnection(c0);
+
+ cr.addConnection(c0);
+ cr.addConnection(c1);
+ cr.delConnection(c0);
+ EXPECT_THROW(cr.delConnection(c0), std::exception);
+ cr.delConnection(c1);
+ EXPECT_THROW(cr.delConnection(c1), std::exception);
+}
+
+TEST_F(ConnectionRegistryTest, test_setId)
+{
+ boost::asio::io_context ioc{1};
+ boost::asio::ip::tcp::socket ts{ioc};
+
+ ConnectionRegistry::connection c {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts))};
+ 
+ ConnectionRegistry cr{};
+
+ EXPECT_THROW(cr.setId(c, "id1"), std::exception);
+ cr.addConnection(c);
+ cr.setId(c, "id2");
+}
+
+TEST_F(ConnectionRegistryTest, test_dump)
+{
+ boost::asio::io_context ioc{1};
+ boost::asio::ip::tcp::socket ts{ioc};
+
+ ConnectionRegistry::connection c {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts))};
+ 
+ ConnectionRegistry cr{};
+
+ cr.addConnection(c);
+ cr.dump();
+
+ cr.setId(c, "id1");
+ cr.dump();
+}
+
+TEST_F(ConnectionRegistryTest, test_iterators)
+{
+ boost::asio::io_context ioc{1};
+ boost::asio::ip::tcp::socket ts{ioc};
+
+ ConnectionRegistry::connection c {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts))};
+ 
+ ConnectionRegistry cr{};
+
+ EXPECT_THROW(cr.begin(""), std::exception);
+ EXPECT_THROW(cr.end(""), std::exception);
+ EXPECT_EQ(std::distance(cr.begin(), cr.end()), 0);
+ 
+ cr.addConnection(c);
+ EXPECT_THROW(cr.begin(""), std::exception);
+ EXPECT_THROW(cr.end(""), std::exception);
+ EXPECT_EQ(std::distance(cr.begin(), cr.end()), 1);
+ 
+ cr.setId(c, "id1");
+
+ EXPECT_EQ(std::distance(cr.begin("id1"), cr.end("id1")), 1);
+ EXPECT_EQ(std::distance(cr.begin(), cr.end()), 1);
+}
+
+TEST_F(ConnectionRegistryTest, test_guard)
+{
+ boost::asio::io_context ioc{1};
+ boost::asio::ip::tcp::socket ts{ioc};
+
+ ConnectionRegistry::connection c {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts))};
+ 
+ ConnectionRegistry cr{};
+
+ {
+  ConnectionRegistry::RegistryGuard rg{cr, c};
+
+  EXPECT_THROW(cr.addConnection(c), std::exception);
+ }
+
+ EXPECT_THROW(cr.delConnection(c), std::exception);
+}
+
+TEST_F(ConnectionRegistryTest, number_of_connections)
+{
+ boost::asio::io_context ioc{1};
+
+ boost::asio::ip::tcp::socket ts0{ioc};
+ ConnectionRegistry::connection c0 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts0))};
+ 
+ boost::asio::ip::tcp::socket ts1{ioc};
+ ConnectionRegistry::connection c1 {std::make_shared<ConnectionRegistry::connection::element_type>(std::move(ts1))};
+ 
+ ConnectionRegistry cr{};
+
+ EXPECT_EQ(cr.number_of_connections(), 0);
+ cr.addConnection(c0);
+ EXPECT_EQ(cr.number_of_connections(), 1);
+ cr.addConnection(c1);
+ EXPECT_EQ(cr.number_of_connections(), 2);
+ cr.delConnection(c0);
+ EXPECT_EQ(cr.number_of_connections(), 1);
+ cr.delConnection(c1);
+ EXPECT_EQ(cr.number_of_connections(), 0);
+}
+
diff --git a/tests/test-diff.cpp b/tests/test-diff.cpp
new file mode 100644
index 0000000..d09c58e
--- /dev/null
+++ b/tests/test-diff.cpp
@@ -0,0 +1,199 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <string>
+#include <system_error>
+
+#include <stdlib.h>
+
+#include <boost/property_tree/ptree.hpp>
+
+#include "libreichwein/file.h"
+
+#include "diff.h"
+
+namespace fs = std::filesystem;
+namespace pt = boost::property_tree;
+using namespace Reichwein;
+
+class DiffTest: public ::testing::Test
+{
+protected:
+ DiffTest(){
+ }
+
+ ~DiffTest(){
+ }
+};
+
+TEST_F(DiffTest, constructor)
+{
+ // empty constructor
+ {
+  Diff d{};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data/></diff>");
+ }
+
+ // constructor via xml diff
+ {
+  EXPECT_THROW(Diff d{""}, std::exception);
+ }
+ {
+  EXPECT_THROW(Diff d{"<diff><begin></begin></diff>"}, std::exception);
+  EXPECT_THROW(Diff d{"<diff><end>0</end><data>abc</data></diff>"}, std::exception);
+  EXPECT_THROW(Diff d{"<diff><start>0</start><data>abc</data></diff>"}, std::exception);
+  EXPECT_THROW(Diff d{"<diff><start>0</start><end>0</end></diff>"}, std::exception);
+  EXPECT_THROW(Diff d{"<diff><start>5</start><end>0</end><data>abc</data></diff>"}, std::exception);
+  EXPECT_THROW(Diff d{"<diff><start></start><end>0</end><data>abc</data></diff>"}, std::exception);
+ }
+
+ {
+  Diff d{"<diff><start>0</start><end>0</end><data>abc</data></diff>"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data>abc</data></diff>");
+ }
+
+ {
+  Diff d{"<diff><start>5</start><end>5</end><data>abc</data></diff>"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>5</start><end>5</end><data>abc</data></diff>");
+ }
+
+ {
+  Diff d{"<diff><start>5</start><end>50</end><data>abc</data></diff>"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>5</start><end>50</end><data>abc</data></diff>");
+ }
+ 
+ // constructor via ptree
+ {
+  pt::ptree ptree;
+  EXPECT_THROW(Diff d{ptree}, std::exception);
+  
+  ptree.put("diff.start", 0);
+  ptree.put("diff.end", 0);
+  ptree.put("diff.data", "abc");
+  Diff d{ptree};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data>abc</data></diff>");
+ }
+
+ // constructor via versions
+ {
+  Diff d{"", ""};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data/></diff>");
+ }
+ {
+  Diff d{"a", "a"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data/></diff>");
+ }
+ {
+  Diff d{"a", "b"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>1</end><data>b</data></diff>");
+ }
+ {
+  Diff d{"0a1", "0b1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>2</end><data>b</data></diff>");
+ }
+ {
+  Diff d{"0abc1", "00b01"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>4</end><data>0b0</data></diff>");
+ }
+ {
+  Diff d{"0ab1", "00b01"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>3</end><data>0b0</data></diff>");
+ }
+ {
+  Diff d{"0abc1", "00b1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>4</end><data>0b</data></diff>");
+ }
+ {
+  Diff d{"0abc1", ""};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>5</end><data/></diff>");
+ }
+ {
+  Diff d{"bc1", "0abc1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data>0a</data></diff>");
+ }
+ {
+  Diff d{"0abc1", "0ab"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>3</start><end>5</end><data/></diff>");
+ }
+ {
+  Diff d{"0abc1", "0abc123"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>5</start><end>5</end><data>23</data></diff>");
+ }
+ {
+  Diff d{"0abc1", "010abc1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data>01</data></diff>");
+ }
+ {
+  Diff d{"0abc1", "0ac1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>2</start><end>3</end><data/></diff>");
+ }
+ {
+  Diff d{"0abc1", "0abxc1"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>3</start><end>3</end><data>x</data></diff>");
+ }
+ {
+  Diff d{"abc", "c"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>2</end><data/></diff>");
+ }
+ {
+  Diff d{"aaaa", "aa"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>2</start><end>4</end><data/></diff>");
+ }
+ {
+  Diff d{"baaaa", "baa"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>3</start><end>5</end><data/></diff>");
+ }
+ {
+  Diff d{"baaaab", "baab"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>3</end><data/></diff>");
+ }
+ {
+  Diff d{"baaaab", "baaaaaaab"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>1</end><data>aaa</data></diff>");
+ }
+}
+
+TEST_F(DiffTest, empty)
+{
+ {
+  Diff d;
+  EXPECT_TRUE(d.empty());
+ }
+
+ {
+  Diff d{"<diff><start>1</start><end>3</end><data/></diff>"};
+  EXPECT_FALSE(d.empty());
+ }
+ 
+ {
+  Diff d{"<diff><start>1</start><end>1</end><data/></diff>"};
+  EXPECT_TRUE(d.empty());
+ }
+ 
+ {
+  Diff d{"<diff><start>1</start><end>1</end><data>abc</data></diff>"};
+  EXPECT_FALSE(d.empty());
+ }
+
+ {
+  Diff d{"<diff><start>0</start><end>0</end><data/></diff>"};
+  EXPECT_TRUE(d.empty());
+ }
+}
+
+TEST_F(DiffTest, diff_create)
+{
+ const char* result {diff_create("0abc1", "0ab")};
+
+ EXPECT_EQ(std::string(result), "<diff><start>3</start><end>5</end><data/></diff>");
+ free((void*)result); // this will be done by javascript side in real scenario
+}
+
+TEST_F(DiffTest, diff_apply)
+{
+ const char* result {diff_apply("0abc1", "<diff><start>3</start><end>5</end><data/></diff>")};
+
+ EXPECT_EQ(std::string(result), "0ab");
+ free((void*)result); // this will be done by javascript side in real scenario
+}
+
diff --git a/tests/test-qrcode.cpp b/tests/test-qrcode.cpp
new file mode 100644
index 0000000..96cfdb0
--- /dev/null
+++ b/tests/test-qrcode.cpp
@@ -0,0 +1,140 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <system_error>
+
+#include "libreichwein/file.h"
+
+#include "qrcode.h"
+
+namespace fs = std::filesystem;
+
+class QRCodeTest: public ::testing::Test
+{
+protected:
+ QRCodeTest(){
+ }
+
+ ~QRCodeTest() override{
+ }
+
+ void SetUp() override
+ {
+  QRCode::init();
+ }
+
+ void TearDown() override
+ {
+ }
+
+};
+
+TEST_F(QRCodeTest, empty)
+{
+ unsigned char empty_png[] = {
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x15, 0x00, 0x00, 0x00, 0x15,
+  0x10, 0x00, 0x00, 0x00, 0x00, 0xdc, 0xec, 0x26, 0x09, 0x00, 0x00, 0x00,
+  0xa7, 0x49, 0x44, 0x41, 0x54, 0x28, 0xcf, 0x7d, 0x92, 0x4b, 0x12, 0xc3,
+  0x30, 0x08, 0x43, 0x79, 0x99, 0xde, 0xff, 0xca, 0xea, 0x82, 0x51, 0xf9,
+  0xc4, 0xae, 0x17, 0x89, 0x01, 0x03, 0x02, 0x89, 0x18, 0x47, 0x8a, 0x00,
+  0x29, 0x2d, 0xe8, 0xb1, 0x4f, 0x86, 0x7b, 0x48, 0x02, 0x7b, 0x57, 0xcc,
+  0xa6, 0xd4, 0x43, 0xd3, 0x96, 0x22, 0x9e, 0x38, 0x9e, 0x9e, 0xe2, 0xf3,
+  0x9c, 0x1f, 0x15, 0xde, 0x81, 0xf5, 0x5d, 0x43, 0x02, 0x3f, 0x3e, 0xd5,
+  0x1f, 0xf8, 0x36, 0xee, 0x88, 0x08, 0xae, 0x59, 0x37, 0xac, 0x00, 0xfe,
+  0xee, 0x9d, 0x76, 0x6f, 0x48, 0x52, 0xb5, 0xcc, 0x7b, 0xfd, 0xed, 0x1f,
+  0x1b, 0xa8, 0xec, 0x64, 0x6d, 0x51, 0x31, 0xab, 0x15, 0xf2, 0xb2, 0xdc,
+  0x91, 0x4e, 0x24, 0x48, 0x7d, 0xa3, 0x53, 0x03, 0xaf, 0x0d, 0x54, 0xd3,
+  0x9b, 0x6c, 0x16, 0xa1, 0x7b, 0x34, 0x29, 0x82, 0xa9, 0x9e, 0x84, 0x61,
+  0xc6, 0x66, 0xfd, 0xc7, 0x9b, 0x73, 0x93, 0x2d, 0xc0, 0xf4, 0xc3, 0x1f,
+  0x65, 0xf1, 0x1b, 0xd8, 0x30, 0xae, 0xca, 0x9a, 0x83, 0x02, 0x1c, 0x94,
+  0xe5, 0x4d, 0x27, 0x42, 0x57, 0x3e, 0x34, 0xde, 0x74, 0x16, 0xf2, 0x2f,
+  0x2f, 0xd5, 0xa5, 0xd0, 0x5a, 0x61, 0xde, 0x49, 0x00, 0x00, 0x00, 0x00,
+  0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
+ };
+ // Test prepared with:
+ //File::setFile("empty.png", QRCode::getQRCode(""));
+ //then: xxd -i tests/empty.png  >> tests/test-qrcode.cpp
+
+ EXPECT_EQ(QRCode::getQRCode(""), std::string(reinterpret_cast<char*>(&empty_png[0]), sizeof(empty_png)));
+}
+
+TEST_F(QRCodeTest, simple)
+{
+ unsigned char simple_png[] = {
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x15, 0x00, 0x00, 0x00, 0x15,
+  0x10, 0x00, 0x00, 0x00, 0x00, 0xdc, 0xec, 0x26, 0x09, 0x00, 0x00, 0x00,
+  0xa5, 0x49, 0x44, 0x41, 0x54, 0x28, 0xcf, 0x75, 0x52, 0xd1, 0x0e, 0xc0,
+  0x40, 0x04, 0x6b, 0x17, 0xff, 0xff, 0xcb, 0xf6, 0xe0, 0x4c, 0x39, 0x93,
+  0x6c, 0x09, 0x47, 0x55, 0x01, 0x9a, 0xb9, 0xbb, 0xbb, 0x03, 0xf9, 0xa9,
+  0x99, 0x86, 0x48, 0x80, 0x8c, 0xe4, 0x2c, 0xd5, 0xb7, 0xcf, 0x2d, 0xa4,
+  0xfa, 0xeb, 0x9b, 0x61, 0xb5, 0xd9, 0x1c, 0x00, 0x9e, 0x2d, 0x2d, 0x88,
+  0xcc, 0xb8, 0xdd, 0x18, 0xa4, 0x3b, 0xa9, 0xad, 0x7f, 0x1b, 0xff, 0x29,
+  0xc0, 0xbd, 0x8a, 0x5c, 0xf0, 0x52, 0xc7, 0x2e, 0x90, 0x2a, 0x91, 0x51,
+  0x4b, 0xfa, 0xc9, 0x2e, 0xfc, 0x40, 0x55, 0x6c, 0xb2, 0xe1, 0xf5, 0x4e,
+  0xd3, 0x7f, 0xaa, 0xf2, 0xa6, 0x52, 0x24, 0x48, 0x77, 0xd9, 0xfa, 0x9c,
+  0x7c, 0xae, 0xf7, 0x52, 0xa0, 0xab, 0xaa, 0x71, 0xeb, 0x5b, 0xa9, 0x21,
+  0xfa, 0x50, 0x67, 0x5b, 0xe3, 0x7a, 0xd0, 0x67, 0x8f, 0x0e, 0xe4, 0x59,
+  0x6c, 0xa4, 0x94, 0x96, 0xda, 0x29, 0xca, 0x80, 0xf5, 0x5c, 0x52, 0x53,
+  0x3d, 0x9a, 0xa3, 0xcb, 0x7d, 0xaf, 0x93, 0xf9, 0xa1, 0xd2, 0xb9, 0xea,
+  0xc6, 0x92, 0xf1, 0x7a, 0x0f, 0xaa, 0xee, 0x8c, 0x03, 0x2f, 0x88, 0x71,
+  0xb5, 0xba, 0xf0, 0x88, 0xba, 0xb0, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45,
+  0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
+ };
+ // Test prepared with:
+ //File::setFile("simple.png", QRCode::getQRCode("abc"));
+ //then: xxd -i tests/simple.png  >> tests/test-qrcode.cpp
+ EXPECT_EQ(QRCode::getQRCode("abc"), std::string(reinterpret_cast<char*>(&simple_png[0]), sizeof(simple_png)));
+}
+
+TEST_F(QRCodeTest, url)
+{
+ unsigned char url_png[] = {
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x1d, 0x00, 0x00, 0x00, 0x1d,
+  0x10, 0x00, 0x00, 0x00, 0x00, 0x23, 0x68, 0xe4, 0x90, 0x00, 0x00, 0x01,
+  0x1f, 0x49, 0x44, 0x41, 0x54, 0x38, 0xcb, 0x75, 0x54, 0xdb, 0x0e, 0xc5,
+  0x30, 0x08, 0x92, 0xa5, 0xff, 0xff, 0xcb, 0x9c, 0x07, 0xe7, 0x41, 0xb4,
+  0x6b, 0xb2, 0x64, 0x36, 0x5e, 0xa8, 0xa0, 0x11, 0x76, 0xc8, 0x08, 0x92,
+  0x24, 0xcb, 0xde, 0x7f, 0x75, 0x4e, 0xba, 0xe7, 0x01, 0x22, 0x48, 0x20,
+  0xbf, 0xb4, 0x2b, 0xe1, 0xfc, 0x03, 0x4e, 0x85, 0xd4, 0x75, 0x06, 0xe5,
+  0xbf, 0xc2, 0xf3, 0xd6, 0x7d, 0x9f, 0x58, 0x07, 0x50, 0xbd, 0xc2, 0x11,
+  0x97, 0xb3, 0x42, 0x3b, 0xd0, 0xb4, 0x33, 0x7c, 0x87, 0x1e, 0x7f, 0x81,
+  0xd7, 0x51, 0x0a, 0x01, 0xbe, 0x25, 0x69, 0x1d, 0xfe, 0xfe, 0xac, 0xea,
+  0x2d, 0x8b, 0x57, 0x50, 0xed, 0xe1, 0xbb, 0x73, 0x3a, 0xaf, 0x65, 0x7b,
+  0xba, 0xd7, 0xea, 0x64, 0x94, 0x93, 0x1c, 0x2a, 0xd8, 0xd3, 0x92, 0x7f,
+  0x95, 0xec, 0x90, 0xa9, 0x9f, 0xb2, 0x94, 0xee, 0x88, 0xf4, 0xba, 0x72,
+  0x4e, 0xf5, 0x5a, 0x69, 0x6b, 0xf0, 0xdc, 0x6b, 0xf8, 0x4b, 0x85, 0xac,
+  0x3f, 0x8a, 0x7c, 0xba, 0x0c, 0x66, 0x78, 0xe7, 0x55, 0xdc, 0x96, 0xda,
+  0x5e, 0x99, 0x2b, 0x38, 0xc5, 0x3f, 0x61, 0x6d, 0x0a, 0x81, 0xf0, 0x56,
+  0x4c, 0x4e, 0x7d, 0xe4, 0x7c, 0x24, 0x9f, 0x39, 0x74, 0xe5, 0x86, 0x86,
+  0x87, 0x04, 0x2e, 0x23, 0xd0, 0xdb, 0x20, 0x8a, 0xe6, 0x60, 0x4f, 0x91,
+  0x7c, 0x32, 0xe6, 0x2f, 0xdc, 0x12, 0x79, 0x31, 0x0a, 0x56, 0xe7, 0xb2,
+  0xef, 0x07, 0x98, 0x8f, 0x8d, 0xe0, 0x6c, 0xd4, 0x04, 0xb6, 0xe1, 0xbf,
+  0xc2, 0x98, 0x97, 0x5d, 0x43, 0xaa, 0x5f, 0xdb, 0xca, 0x6f, 0x57, 0xd3,
+  0xee, 0xe4, 0xec, 0x3e, 0x9c, 0x4d, 0x8e, 0x81, 0xc2, 0x2d, 0x5d, 0x56,
+  0x7e, 0x32, 0x44, 0xbc, 0xed, 0x6a, 0x1a, 0x87, 0xf4, 0x2a, 0xe8, 0x6b,
+  0xad, 0x75, 0x51, 0xfa, 0x66, 0xf4, 0x07, 0x01, 0x97, 0x8d, 0x08, 0x90,
+  0x09, 0xb5, 0xef, 0x64, 0xe7, 0xbf, 0x49, 0x62, 0x8e, 0xfa, 0xec, 0xfb,
+  0x26, 0xad, 0x8d, 0xba, 0x3b, 0xf5, 0xf6, 0xf8, 0x22, 0x95, 0xf7, 0x0f,
+  0x4c, 0x20, 0xaf, 0x2d, 0xca, 0xaf, 0x0d, 0xc5, 0x00, 0x00, 0x00, 0x00,
+  0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
+ };
+ // Test prepared with:
+ //File::setFile("url.png", QRCode::getQRCode("https://reichwein.it/whiteboard"));
+ //then: xxd -i tests/url.png  >> tests/test-qrcode.cpp
+ EXPECT_EQ(QRCode::getQRCode("https://reichwein.it/whiteboard"), std::string(reinterpret_cast<char*>(&url_png[0]), sizeof(url_png)));
+}
+
+TEST_F(QRCodeTest, deterministic)
+{
+ EXPECT_EQ(QRCode::getQRCode("data1"), QRCode::getQRCode("data1"));
+}
+
+TEST_F(QRCodeTest, different_data)
+{
+ EXPECT_NE(QRCode::getQRCode("data1"), QRCode::getQRCode("data2"));
+}
diff --git a/tests/test-storage.cpp b/tests/test-storage.cpp
new file mode 100644
index 0000000..6239f8f
--- /dev/null
+++ b/tests/test-storage.cpp
@@ -0,0 +1,283 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <system_error>
+
+#include "libreichwein/file.h"
+
+#include "config.h"
+#include "storage.h"
+
+namespace fs = std::filesystem;
+using namespace Reichwein;
+using namespace std::string_literals;
+
+namespace {
+ const std::string testConfigFilename{"./test.conf"};
+ const std::string testDbFilename{"./whiteboard.db3"};
+}
+
+class StorageTest: public ::testing::Test
+{
+protected:
+ StorageTest(){
+ }
+
+ ~StorageTest() override{
+ }
+
+ void SetUp() override
+ {
+  File::setFile(testConfigFilename, R"CONFIG(
+<config>
+ <datapath>.</datapath>
+ <maxage>2592000</maxage>
+</config>
+)CONFIG");
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+
+  m_config = std::make_shared<Config>(testConfigFilename);
+ }
+
+ void TearDown() override
+ {
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+  fs::remove(testConfigFilename, ec);
+ }
+
+ std::shared_ptr<Config> m_config;
+};
+
+TEST_F(StorageTest, create)
+{
+ ASSERT_TRUE(!fs::exists(testDbFilename));
+
+ {
+  ASSERT_EQ(m_config->getDataPath(), ".");
+  ASSERT_TRUE(!fs::exists(testDbFilename));
+  Storage storage(*m_config);
+ }
+
+ ASSERT_TRUE(fs::exists(testDbFilename));
+}
+
+TEST_F(StorageTest, getNumberOfDocuments)
+{
+ Storage storage(*m_config);
+ EXPECT_EQ(storage.getNumberOfDocuments(), 0UL);
+ storage.setDocument("123", "abc");
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ storage.setDocument("def", "xyz");
+ EXPECT_EQ(storage.getNumberOfDocuments(), 2UL);
+}
+
+TEST_F(StorageTest, cleanup_empty)
+{
+ Storage storage(*m_config);
+ EXPECT_EQ(storage.getNumberOfDocuments(), 0UL);
+ storage.cleanup();
+ EXPECT_EQ(storage.getNumberOfDocuments(), 0UL);
+}
+
+TEST_F(StorageTest, cleanup)
+{
+ Storage storage(*m_config);
+ EXPECT_EQ(storage.getNumberOfDocuments(), 0UL);
+ storage.setDocument("123", "abc");
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ storage.cleanup();
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+}
+
+TEST_F(StorageTest, exists)
+{
+ Storage storage(*m_config);
+ EXPECT_EQ(storage.exists(""), false);
+ EXPECT_EQ(storage.exists("0"), false);
+ EXPECT_EQ(storage.exists("123"), false);
+ EXPECT_EQ(storage.exists("abcdz"), false);
+
+ storage.setDocument("", "abc");
+ EXPECT_EQ(storage.exists(""), true);
+ storage.setDocument("0", "abc");
+ EXPECT_EQ(storage.exists("0"), true);
+ storage.setDocument("123", "abc");
+ EXPECT_EQ(storage.exists("123"), true);
+ storage.setDocument("abcdz", "abc");
+ EXPECT_EQ(storage.exists("abcdz"), true);
+}
+
+TEST_F(StorageTest, setDocument)
+{
+ Storage storage(*m_config);
+ storage.setDocument("0", "abc");
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ EXPECT_EQ(storage.getDocument("0"), "abc");
+}
+
+TEST_F(StorageTest, touchDocument)
+{
+ Storage storage(*m_config);
+ EXPECT_THROW(storage.touchDocument("0"), std::exception);
+ storage.setDocument("0", "abc");
+ storage.touchDocument("0");
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ EXPECT_EQ(storage.getDocument("0"), "abc");
+}
+
+TEST_F(StorageTest, setRevision)
+{
+ Storage storage(*m_config);
+ storage.setDocument("0", "abc");
+ storage.setRevision("0", 123);
+
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ EXPECT_EQ(storage.getRevision("0"), 123);
+ 
+ try {
+  storage.setRevision("1", 123);
+  FAIL();
+ } catch(const std::exception& ex) {
+  EXPECT_EQ("Unable to set revision for id 1"s, ex.what());
+ } catch(...) {
+  FAIL();
+ }
+}
+
+TEST_F(StorageTest, setCursorPos)
+{
+ Storage storage(*m_config);
+ storage.setDocument("0", "abc");
+ storage.setCursorPos("0", 1234);
+
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ EXPECT_EQ(storage.getCursorPos("0"), 1234);
+ 
+ try {
+  storage.setCursorPos("1", 12345);
+  FAIL();
+ } catch(const std::exception& ex) {
+  EXPECT_EQ("Unable to set cursor position for id 1"s, ex.what());
+ } catch(...) {
+  FAIL();
+ }
+}
+
+TEST_F(StorageTest, setRow)
+{
+ Storage storage(*m_config);
+ storage.setRow("0", "abc", 56, 67);
+
+ EXPECT_EQ(storage.getNumberOfDocuments(), 1UL);
+ EXPECT_EQ(storage.getDocument("0"), "abc");
+ EXPECT_EQ(storage.getRevision("0"), 56);
+ EXPECT_EQ(storage.getCursorPos("0"), 67);
+}
+
+TEST_F(StorageTest, getDocument)
+{
+ Storage storage(*m_config);
+ storage.setDocument("0", "xyz");
+ storage.setDocument("0bc", "xyz2");
+ storage.setDocument("iabc", "xyz3");
+ storage.setDocument("zxy", "xyz4");
+ 
+ EXPECT_EQ(storage.getDocument("0"), "xyz");
+}
+
+TEST_F(StorageTest, getRevision)
+{
+ Storage storage(*m_config);
+ storage.setRow("0", "abc", 123, 456);
+ 
+ EXPECT_EQ(storage.getRevision("0"), 123);
+}
+
+TEST_F(StorageTest, getCursorPos)
+{
+ Storage storage(*m_config);
+ storage.setRow("0", "abc", 123, 456);
+ 
+ EXPECT_EQ(storage.getCursorPos("0"), 456);
+}
+
+TEST_F(StorageTest, getRow)
+{
+ Storage storage(*m_config);
+ storage.setRow("0", "abc", 123, 456);
+
+ auto row{storage.getRow("0")};
+ EXPECT_EQ(std::get<0>(row), "abc");
+ EXPECT_EQ(std::get<1>(row), 123);
+ EXPECT_EQ(std::get<2>(row), 456);
+}
+
+TEST_F(StorageTest, revision_increment)
+{
+ Storage storage(*m_config);
+ storage.setDocument("0", "xyz");
+ storage.setDocument("0bc", "xyz2");
+ storage.setDocument("iabc", "xyz3");
+ 
+ EXPECT_EQ(storage.getRevision("0"), 0);
+ EXPECT_EQ(storage.getRevision("0bc"), 0);
+ EXPECT_EQ(storage.getRevision("iabc"), 0);
+ 
+ storage.setDocument("0bc", "xyz234");
+ EXPECT_EQ(storage.getRevision("0bc"), 1);
+ 
+ storage.setDocument("0bc", "xyz2345");
+ EXPECT_EQ(storage.getRevision("0"), 0);
+ EXPECT_EQ(storage.getRevision("0bc"), 2);
+ EXPECT_EQ(storage.getRevision("iabc"), 0);
+}
+
+TEST_F(StorageTest, generate_id)
+{
+ Storage storage(*m_config);
+ for (int i = 0; i < 100; i++) {
+  std::string a{storage.generate_id()};
+  std::string b{storage.generate_id()};
+
+  EXPECT_NE(a, b);
+  EXPECT_NE(a, "");
+  EXPECT_NE(b, "");
+
+  EXPECT_GE(a.size(), 6);
+
+  for (char c: a + b) {
+   EXPECT_TRUE((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z'));
+  }
+ }
+}
+
+TEST_F(StorageTest, checksum32)
+{
+ EXPECT_EQ(checksum32(""), 0);
+ EXPECT_EQ(checksum32("0"), 48);
+ EXPECT_EQ(checksum32("\x00"), 0);
+ EXPECT_EQ(checksum32("123"), 1073741862);
+ EXPECT_EQ(checksum32("a"), 97);
+ EXPECT_EQ(checksum32("ab"), 82);
+ EXPECT_EQ(checksum32("abc"), 1073741898);
+}
+
+TEST_F(StorageTest, db_size)
+{
+ Storage storage(*m_config);
+ auto dbsize_gross{storage.dbsize_gross()};
+ auto dbsize_net{storage.dbsize_net()};
+
+ EXPECT_LE(0, storage.dbsize_net());
+ EXPECT_LE(storage.dbsize_net(), storage.dbsize_gross());
+ 
+ storage.setDocument("0", "xyz");
+ 
+ EXPECT_LE(dbsize_net, storage.dbsize_net());
+ EXPECT_LE(dbsize_gross, storage.dbsize_gross());
+}
+
diff --git a/tests/test-whiteboard.cpp b/tests/test-whiteboard.cpp
new file mode 100644
index 0000000..3f70bcf
--- /dev/null
+++ b/tests/test-whiteboard.cpp
@@ -0,0 +1,255 @@
+#include <gtest/gtest.h>
+
+#include <cstring>
+#include <filesystem>
+#include <memory>
+#include <regex>
+#include <string>
+#include <system_error>
+#include <thread>
+
+#include <boost/process/child.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/beast/core.hpp>
+#include <boost/beast/http.hpp>
+#include <boost/beast/websocket.hpp>
+#include <boost/asio/buffer.hpp>
+#include <boost/asio/buffers_iterator.hpp>
+#include <boost/asio/connect.hpp>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/local/stream_protocol.hpp>
+
+#include <unistd.h>
+
+#include "libreichwein/file.h"
+#include "libreichwein/process.h"
+
+#include "config.h"
+#include "storage.h"
+#include "whiteboard.h"
+
+namespace bp = boost::process;
+namespace fs = std::filesystem;
+using namespace Reichwein;
+using namespace std::string_literals;
+
+namespace {
+ const fs::path webserverConfigFilename{"./webserver.conf"};
+
+ const fs::path testConfigFilename{"./whiteboard.conf"};
+ const fs::path testDbFilename{"./whiteboard.db3"};
+}
+
+class WhiteboardTest: public ::testing::Test
+{
+protected:
+ WhiteboardTest(){
+ }
+
+ ~WhiteboardTest() override{
+ }
+
+ void SetUp() override
+ {
+  File::setFile(testConfigFilename, R"CONFIG(
+<config>
+ <port>::1:9876</port>
+ <datapath>.</datapath>
+ <maxage>2592000</maxage>
+ <threads>4</threads>
+ <maxconnections>3</maxconnections>
+</config>
+)CONFIG");
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+
+  m_config = std::make_shared<Config>(testConfigFilename);
+
+  m_pid = fork();
+  if (m_pid == -1) {
+   throw std::runtime_error("Error on fork(): "s + strerror(errno));
+  } else if (m_pid == 0) { // child
+   Whiteboard whiteboard;
+   std::vector<std::string> argvv{{"whiteboard", "-c", testConfigFilename.generic_string()}};
+   char* argv[] = {argvv[0].data(), argvv[1].data(), argvv[2].data(), nullptr};
+   whiteboard.run(argvv.size(), argv);
+   exit(0);
+  }
+  Process::wait_for_pid_listening_on(m_pid, 9876);
+  std::this_thread::sleep_for(std::chrono::milliseconds(20));
+ }
+
+ void TearDown() override
+ {
+  if (m_pid == 0)
+   throw std::runtime_error("Whiteboard not running on requesting SIGTERM");
+
+  if (kill(m_pid, SIGTERM) != 0)
+   throw std::runtime_error("Unable to SIGTERM Whiteboard");
+
+  if (int result = waitpid(m_pid, NULL, 0); result != m_pid)
+   throw std::runtime_error("waitpid returned "s + std::to_string(result));
+
+  std::error_code ec;
+  fs::remove(testDbFilename, ec);
+  fs::remove(testConfigFilename, ec);
+ }
+
+ std::shared_ptr<Config> m_config;
+ pid_t m_pid{};
+};
+
+class WebsocketClient
+{
+public:
+ WebsocketClient()
+ {
+  std::string host = "::1";
+  auto const  port = "9876" ;
+
+  // These objects perform our I/O
+  boost::asio::ip::tcp::resolver resolver{ioc_};
+  ws_ = std::make_unique<boost::beast::websocket::stream<boost::asio::ip::tcp::socket>>(ioc_);
+
+  // Look up the domain name
+  resolver_results_ = resolver.resolve(host, port);
+
+  connect();
+  handshake();
+ }
+
+ void connect()
+ {
+  // Make the connection on the IP address we get from a lookup
+  ep_ = boost::asio::connect(boost::beast::get_lowest_layer(*ws_), resolver_results_);
+ }
+
+ void handshake()
+ {
+  // Update the host_ string. This will provide the value of the
+  // Host HTTP header during the WebSocket handshake.
+  // See https://tools.ietf.org/html/rfc7230#section-5.4
+  std::string host{"[::1]:9876"};
+
+  // Set a decorator to change the User-Agent of the handshake
+  ws_->set_option(boost::beast::websocket::stream_base::decorator(
+      [](boost::beast::websocket::request_type& req)
+      {
+          req.set(boost::beast::http::field::user_agent,
+              std::string("Reichwein.IT Test Websocket Client"));
+      }));
+  
+  // Perform the websocket handshake
+  ws_->handshake(host, "/");
+
+ }
+
+ void write(const std::string& data)
+ {
+  ws_->write(boost::asio::buffer(data));
+ }
+
+ std::string read()
+ {
+  boost::beast::flat_buffer buffer;
+  ws_->read(buffer);
+  return {boost::asio::buffers_begin(buffer.data()), boost::asio::buffers_end(buffer.data())};
+ }
+
+ ~WebsocketClient()
+ {
+ }
+
+ bool is_open()
+ {
+  return ws_->is_open();
+ }
+
+private:
+ boost::asio::io_context ioc_;
+ boost::asio::ip::tcp::resolver::results_type resolver_results_;
+ std::unique_ptr<boost::beast::websocket::stream<boost::asio::ip::tcp::socket>> ws_;
+ boost::asio::ip::tcp::endpoint ep_;
+};
+
+//
+// tests via websocket server in separate process (hides coverage)
+//
+
+TEST_F(WhiteboardTest, websocket_server_connection)
+{
+ WebsocketClient wc;
+}
+
+TEST_F(WhiteboardTest, websocket_server_generate_id)
+{
+ WebsocketClient wc;
+
+ wc.write("<request><command>newid</command></request>");
+ std::string result0 {wc.read()};
+ ASSERT_TRUE(boost::algorithm::starts_with(result0, "<serverinfo><type>newid</type><id>"));
+ ASSERT_TRUE(boost::algorithm::ends_with(result0, "</id></serverinfo>"));
+ ASSERT_EQ(result0.size(), 58);
+ 
+ wc.write("<request><command>newid</command></request>");
+ std::string result1 {wc.read()};
+ ASSERT_TRUE(boost::algorithm::starts_with(result1, "<serverinfo><type>newid</type><id>"));
+ ASSERT_TRUE(boost::algorithm::ends_with(result1, "</id></serverinfo>"));
+ ASSERT_EQ(result1.size(), 58);
+ 
+ ASSERT_NE(result0, result1);
+}
+
+// check number of threads as configured
+TEST_F(WhiteboardTest, threads)
+{
+ ASSERT_GE(Process::number_of_threads(m_pid), 4);
+}
+
+TEST_F(WhiteboardTest, max_connections)
+{
+ WebsocketClient wc1;
+ std::this_thread::sleep_for(std::chrono::milliseconds(20));
+ ASSERT_TRUE(wc1.is_open());
+ 
+ WebsocketClient wc2;
+ std::this_thread::sleep_for(std::chrono::milliseconds(20));
+ ASSERT_TRUE(wc2.is_open());
+ 
+ WebsocketClient wc3;
+ std::this_thread::sleep_for(std::chrono::milliseconds(20));
+ ASSERT_TRUE(wc3.is_open());
+ 
+ ASSERT_THROW(WebsocketClient wc4, std::exception);
+}
+
+TEST_F(WhiteboardTest, id)
+{
+ WebsocketClient wc;
+
+ wc.write("<request><command>getfile</command><id>1</id></request>");
+ std::string result {wc.read()};
+
+ EXPECT_EQ(result, "<serverinfo><type>getfile</type><data/><revision>0</revision><pos>0</pos></serverinfo>");
+ 
+ wc.write("<request><command>getfile</command><id></id></request>");
+ result = wc.read();
+ EXPECT_EQ(result, "<serverinfo><type>error</type><message>Message handling error: Invalid id (empty)</message></serverinfo>");
+ 
+ wc.write("<request><command>getfile</command><id>01234567890123456789</id></request>");
+ result = wc.read();
+ EXPECT_EQ(result, "<serverinfo><type>error</type><message>Message handling error: Invalid id (size &gt; 16)</message></serverinfo>");
+ 
+ wc.write("<request><command>getfile</command><id>X</id></request>");
+ result = wc.read();
+ EXPECT_EQ(result, "<serverinfo><type>error</type><message>Message handling error: Invalid id char: X</message></serverinfo>");
+ 
+ wc.write("<request><command>getfile</command><id>a.</id></request>");
+ result = wc.read();
+ EXPECT_EQ(result, "<serverinfo><type>error</type><message>Message handling error: Invalid id char: .</message></serverinfo>");
+ 
+ wc.write("<request><command>getfile</command><id>a$b</id></request>");
+ result = wc.read();
+ EXPECT_EQ(result, "<serverinfo><type>error</type><message>Message handling error: Invalid id char: $</message></serverinfo>");
+}
+
diff --git a/webassembly/Makefile b/webassembly/Makefile
new file mode 100644
index 0000000..0487d2a
--- /dev/null
+++ b/webassembly/Makefile
@@ -0,0 +1,32 @@
+TARGET=libwhiteboard.wasm
+TARGETJS=$(TARGET:.wasm=.js)
+
+OBJS=diff.o
+
+CXX=em++
+
+CXXFLAGS=-I./include -O2 -std=c++20
+LDFLAGS=-s WASM=1 -s EXPORTED_FUNCTIONS="['_diff_create', '_diff_apply', '_free']"
+# Note: Instead of the above explicit EXPORTED_FUNCTIONS, the following causes ~7x wasm file size:
+#-s LINKABLE=1 -s EXPORT_ALL=1
+
+default: $(TARGET)
+
+$(OBJS): include
+
+include:
+	mkdir include
+	cp -r /usr/include/boost include/boost
+
+$(TARGET): $(OBJS)
+	$(CXX) $(LDFLAGS) $(OBJS) -o $(TARGETJS)
+	cp $(TARGETJS) $(TARGET) ../html/
+
+diff.o: ../diff.cpp
+	$(CXX) -c $< $(CXXFLAGS) -o $@
+	# run again in case em++ just asked to re-run (on pbuilder/buildd)
+	test -e $@ || $(CXX) -c $< $(CXXFLAGS) -o $@
+
+clean:
+	-rm -f *.o *.js *.wasm *.html
+	-rm -rf include
diff --git a/webserver.conf.example b/webserver.conf.example
new file mode 100644
index 0000000..9193a5b
--- /dev/null
+++ b/webserver.conf.example
@@ -0,0 +1,8 @@
+   <path requested="/whiteboard">
+    <plugin>static-files</plugin>
+    <target>/usr/lib/whiteboard/html</target>
+   </path>
+   <path requested="/whiteboard/websocket">
+    <plugin>websocket</plugin>
+    <target>127.0.0.1:9014</target>
+   </path>
diff --git a/whiteboard.conf b/whiteboard.conf
new file mode 100644
index 0000000..4622db9
--- /dev/null
+++ b/whiteboard.conf
@@ -0,0 +1,34 @@
+<config>
+ <!--
+  datapath: location in filesystem to store whiteboard data
+  Example: /var/lib/whiteboard
+ -->
+ <datapath>/var/lib/whiteboard</datapath>
+
+ <!--
+  port: socket to listen on for websocket
+  Example: ::1:8765
+ -->
+ <port>::1:9014</port>
+
+ <!--
+  Maximum age of individual whiteboard pages in seconds.
+  Older pages will be removed by whiteboard-cleanup and crond.
+  Example: 2592000 (~30 days)
+ -->
+ <maxage>2592000</maxage>
+ 
+ <!--
+  Number of threads to use
+  Example: 4
+ -->
+ <threads>4</threads>
+ 
+ <!--
+  Maximum number of total concurrent websocket connections. Above this limit,
+  new connections will be rejected until old ones are closed.
+  Example: 500
+  Default: 1000
+ -->
+ <maxconnections>500</maxconnections>
+</config>
diff --git a/whiteboard.cpp b/whiteboard.cpp
new file mode 100644
index 0000000..8fb5415
--- /dev/null
+++ b/whiteboard.cpp
@@ -0,0 +1,571 @@
+#include "whiteboard.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/types.h>
+
+#include <chrono>
+#include <initializer_list>
+#include <iostream>
+#include <functional>
+#include <filesystem>
+#include <memory>
+#include <mutex>
+#include <regex>
+#include <sstream>
+#include <string>
+#include <thread>
+#include <unordered_map>
+
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/algorithm/string/trim.hpp>
+#include <boost/property_tree/xml_parser.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/beast/core.hpp>
+#include <boost/beast/http.hpp>
+#include <boost/beast/websocket.hpp>
+#include <boost/beast/version.hpp>
+#include <boost/asio/buffer.hpp>
+#include <boost/asio/buffers_iterator.hpp>
+#include <boost/asio/connect.hpp>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/signal_set.hpp>
+#include <boost/asio/strand.hpp>
+#include <boost/process.hpp>
+
+#include <fmt/core.h>
+
+#include "libreichwein/base64.h"
+#include "libreichwein/file.h"
+#include "libreichwein/tempfile.h"
+#include "libreichwein/xml.h"
+
+#include "config.h"
+#include "diff.h"
+#include "qrcode.h"
+#include "storage.h"
+
+namespace pt = boost::property_tree;
+using namespace std::string_literals;
+using namespace std::placeholders;
+namespace fs = std::filesystem;
+namespace bp = boost::process;
+
+namespace {
+
+ void usage() {
+  std::cout <<
+   "Usage: \n"
+   " whiteboard [options]\n"
+   "\n"
+   "Options:\n"
+   " -c <path> : specify configuration file including path\n"
+   " -C : clean up database according to timeout rules (config: maxage)\n"
+   " -h : this help\n"
+   "\n"
+   "Without options, whiteboard will be started as websocket application"
+   << std::endl;
+ }
+
+} // namespace
+
+Whiteboard::Whiteboard()
+{
+}
+
+namespace {
+
+pt::ptree make_ptree(const std::initializer_list<std::pair<std::string, std::string>>& key_values)
+{
+ pt::ptree ptree;
+ for (const auto& i: key_values) {
+  ptree.put(fmt::format("serverinfo.{}", i.first), i.second);
+ }
+
+ return ptree;
+}
+
+std::string make_xml(const std::initializer_list<std::pair<std::string, std::string>>& key_values)
+{
+ pt::ptree ptree{make_ptree(key_values)};
+ return Reichwein::XML::plain_xml(ptree);
+}
+
+// throws on invalid id
+void validate_id(const std::string& id) {
+ if (!id.size())
+  throw std::runtime_error("Invalid id (empty)");
+ 
+ if (id.size() > 16)
+  throw std::runtime_error("Invalid id (size > 16)");
+
+ for (const auto c: id) {
+  if (!((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z')))
+   throw std::runtime_error("Invalid id char: "s + c);
+ }
+}
+
+} // namespace
+
+class session: public std::enable_shared_from_this<session>
+{
+public:
+ using connection = std::shared_ptr<boost::beast::websocket::stream<boost::asio::ip::tcp::socket>>;
+ 
+ session(ConnectionRegistry& registry, Storage& storage, std::mutex& storage_mutex, boost::asio::ip::tcp::socket socket):
+  m_registry(registry),
+  m_storage(storage),
+  m_storage_mutex(storage_mutex),
+  m_ws(std::make_shared<connection::element_type>(std::move(socket))),
+  m_connection_guard(m_registry, m_ws)
+ {
+ }
+
+ ~session()
+ {
+  if (m_stats_timer)
+   m_stats_timer->cancel();
+  m_stats_timer = nullptr;
+ }
+
+ void do_read_handshake()
+ {
+  // Set a decorator to change the Server of the handshake
+  m_ws->set_option(boost::beast::websocket::stream_base::decorator(
+      [](boost::beast::websocket::response_type& res)
+      {
+       res.set(boost::beast::http::field::server,
+           std::string("Reichwein.IT Whiteboard"));
+      }));
+
+  boost::beast::http::async_read(m_ws->next_layer(), m_buffer, m_parser,
+                                 boost::asio::bind_executor(m_ws->next_layer().get_executor(), boost::beast::bind_front_handler(&session::on_read_handshake, shared_from_this())));
+ }
+
+ void on_read_handshake(boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+  if (ec) {
+   std::cerr << "Error on session handshake read: " << ec.message() << std::endl;
+  } else {
+   do_accept_handshake();
+  }
+ }
+
+ void do_accept_handshake()
+ {
+  m_req = m_parser.get();
+
+  m_ws->async_accept(m_req, boost::beast::bind_front_handler(&session::on_accept_handshake, shared_from_this()));
+ }
+
+ void on_accept_handshake(boost::beast::error_code ec)
+ {
+  if (ec) {
+   std::cerr << "Error on session handshake accept: " << ec.message() << std::endl;
+  } else {
+   do_read();
+  }
+ }
+
+ void do_read()
+ {
+  if (m_buffer.size() > 0) {
+   m_buffer.consume(m_buffer.size());
+  }
+
+  m_ws->async_read(m_buffer, boost::beast::bind_front_handler(&session::on_read, shared_from_this()));
+ }
+
+ void on_read(boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+  if (ec) {
+   if (ec != boost::beast::websocket::error::closed)
+    std::cerr << "Error on session read: " << ec.message() << std::endl;
+  } else {
+   do_write();
+  }
+ }
+
+ void do_write()
+ {
+  m_ws->text(m_ws->got_text());
+  std::string data(boost::asio::buffers_begin(m_buffer.data()), boost::asio::buffers_end(m_buffer.data()));
+  data = handle_request(data);
+  if (m_buffer.size() > 0) {
+   m_buffer.consume(m_buffer.size());
+  }
+  if (data.size() > 0) {
+   boost::beast::ostream(m_buffer) << data;
+   m_ws->async_write(m_buffer.data(),
+                     boost::asio::bind_executor(m_ws->next_layer().get_executor(),
+                                                boost::beast::bind_front_handler(&session::on_write, shared_from_this())));
+  } else {
+   do_read();
+  }
+ }
+
+ void on_write(boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+
+  if (ec) {
+   std::cerr << "Error on session write: " << ec.message() << std::endl;
+  } else {
+   do_read();
+  }
+ }
+
+ void run()
+ {
+  do_read_handshake();
+ }
+
+ void on_write_notify(std::shared_ptr<std::string> data, std::shared_ptr<boost::asio::const_buffer> buffer, boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+
+  if (ec) {
+   std::cerr << "Error on session write notify: " << ec.message() << std::endl;
+  }
+ }
+
+ void notify_other_connections_diff(const std::string& id, const Diff& diff)
+ {
+  std::for_each(m_registry.begin(id), m_registry.end(id), [&](const connection& ci)
+                {
+                 if (m_ws != ci) {
+                  pt::ptree ptree {make_ptree({
+                    {"type", "getdiff"},
+                    {"revision", std::to_string(m_storage.getRevision(id))},
+                    {"pos", std::to_string(m_storage.getCursorPos(id)) }
+                    })};
+                  ptree.put_child("serverinfo.diff", diff.get_structure().get_child("diff"));
+                  auto data{std::make_shared<std::string>(Reichwein::XML::plain_xml(ptree))};
+                  auto buffer{std::make_shared<boost::asio::const_buffer>(data->data(), data->size())};
+                  try {
+                   ci->async_write(*buffer, boost::asio::bind_executor(ci->next_layer().get_executor(),
+                                                                       boost::beast::bind_front_handler(&session::on_write_notify, shared_from_this(), data, buffer)));
+                  } catch (const std::exception& ex) {
+                   std::cerr << "Warning: Notify getdiff write for " << ci << " not possible, id " << id << std::endl;
+                   m_registry.dump();
+                  }
+                 }
+                });
+ }
+
+ void notify_other_connections_pos(const std::string& id)
+ {
+  std::for_each(m_registry.begin(id), m_registry.end(id), [&](const connection& ci)
+                {
+                 if (m_ws != ci) {
+                  auto data{std::make_shared<std::string>(make_xml({
+                    {"type", "getpos"},
+                    {"pos", std::to_string(m_storage.getCursorPos(id)) }
+                    }))};
+                  auto buffer{std::make_shared<boost::asio::const_buffer>(data->data(), data->size())};
+                  try {
+                   ci->async_write(*buffer, boost::asio::bind_executor(ci->next_layer().get_executor(),
+                                                                       boost::beast::bind_front_handler(&session::on_write_notify, shared_from_this(), data, buffer)));
+                  } catch (const std::exception& ex) {
+                   std::cerr << "Warning: Notify getpos write for " << ci << " not possible, id " << id << std::endl;
+                   m_registry.dump();
+                  }
+                 }
+                });
+ }
+
+ std::string stats_xml()
+ {
+  return make_xml({
+                  {"type", "stats" },
+                  {"dbsizegross", std::to_string(m_storage.dbsize_gross()) },
+                  {"dbsizenet", std::to_string(m_storage.dbsize_net()) },
+                  {"numberofdocuments", std::to_string(m_storage.getNumberOfDocuments()) },
+                  {"numberofconnections", std::to_string(m_registry.number_of_connections()) },
+                  }); 
+ }
+
+ void on_write_stats(std::shared_ptr<std::string> data, std::shared_ptr<boost::asio::const_buffer> buffer, boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+
+  if (ec) {
+   std::cerr << "Error on session write stats: " << ec.message() << std::endl;
+  }
+ }
+
+ void stats_callback(const boost::system::error_code&)
+ {
+  if (m_stats_timer) {
+   auto data{std::make_shared<std::string>(stats_xml())};
+   auto buffer{std::make_shared<boost::asio::const_buffer>(data->data(), data->size())};
+   m_ws->async_write(*buffer, boost::asio::bind_executor(m_ws->next_layer().get_executor(),
+                                                         boost::beast::bind_front_handler(&session::on_write_stats, shared_from_this(), data, buffer)));
+
+   m_stats_timer->expires_at(m_stats_timer->expires_at() + boost::asio::chrono::seconds(5));
+   m_stats_timer->async_wait(boost::beast::bind_front_handler(&session::stats_callback, this));
+  }
+ }
+
+ void setup_stats_timer()
+ {
+  if (!m_stats_timer) {
+   m_stats_timer = std::make_shared<boost::asio::steady_timer>(m_ws->next_layer().get_executor(), boost::asio::chrono::seconds(5));
+   m_stats_timer->async_wait(boost::beast::bind_front_handler(&session::stats_callback, this));
+  }
+ }
+
+ std::string handle_request(const std::string& request)
+ {
+  try {
+   std::lock_guard<std::mutex> lock(m_storage_mutex);
+   
+   pt::ptree xml;
+   std::istringstream ss{request};
+   pt::xml_parser::read_xml(ss, xml);
+
+   std::string command {xml.get<std::string>("request.command")};
+
+   if (command == "modify") {
+    std::string id {xml.get<std::string>("request.id")};
+    validate_id(id);
+    
+    int baserev {xml.get<int>("request.baserev")};
+    if (baserev != m_storage.getRevision(id))
+     return make_xml({{"type", "error"}, {"message", "Bad base revision ("s + std::to_string(baserev) + "). Current: "s + std::to_string(m_storage.getRevision(id)) }});
+
+    pt::ptree ptree;
+    ptree.put_child("diff", xml.get_child("request.diff"));
+    Diff d{ptree};
+    if (!d.empty()) {
+     std::string data {m_storage.getDocument(id)};
+     data = d.apply(data);
+
+     m_storage.setDocument(id, data);
+     m_registry.setId(m_ws, id);
+     notify_other_connections_diff(id, d);
+    }
+    
+    int pos {xml.get<int>("request.pos")};
+    if (m_storage.getCursorPos(id) != pos) {
+     m_storage.setCursorPos(id, pos);
+     notify_other_connections_pos(id);
+    }
+    return make_xml({{"type", "modify"}, {"revision", std::to_string(m_storage.getRevision(id)) }});
+   } else if (command == "cursorpos") {
+    std::string id {xml.get<std::string>("request.id")};
+    validate_id(id);
+    int pos {xml.get<int>("request.pos")};
+    if (m_storage.getCursorPos(id) != pos) {
+     m_storage.setCursorPos(id, pos);
+     notify_other_connections_pos(id);
+    }
+    return {};
+   } else if (command == "getfile") {
+    std::string id {xml.get<std::string>("request.id")};
+    validate_id(id);
+
+    std::string filedata;
+    try {
+     filedata = m_storage.getDocument(id);
+    } catch (const std::runtime_error&) {
+     m_storage.setDocument(id, filedata);
+    }
+
+    if (filedata.size() > 30000000)
+     throw std::runtime_error("File too big");
+    m_registry.setId(m_ws, id);
+
+    return make_xml({
+                    {"type", "getfile"},
+                    {"data", filedata},
+                    {"revision", std::to_string(m_storage.getRevision(id)) },
+                    {"pos", std::to_string(m_storage.getCursorPos(id)) }
+                    }); 
+   } else if (command == "getpos") {
+    std::string id {xml.get<std::string>("request.id")};
+    validate_id(id);
+
+    return make_xml({
+                    {"type", "getpos"},
+                    {"pos", std::to_string(m_storage.getCursorPos(id)) }
+                    }); 
+   } else if (command == "newid") {
+    return make_xml({{"type", "newid"}, {"id", m_storage.generate_id()}}); 
+   } else if (command == "qrcode") {
+    std::string url{xml.get<std::string>("request.url")};
+    
+    if (url.size() > 1000)
+     throw std::runtime_error("URL too big");
+
+    std::string pngdata {QRCode::getQRCode(url)};
+
+    return make_xml({{"type", "qrcode"}, {"png", Reichwein::Base64::encode64(pngdata)}});
+   } else if (command == "getversion") {
+    return make_xml({
+                    {"type", "version"},
+                    {"version", WHITEBOARD_VERSION }
+                    }); 
+   } else if (command == "getstats") {
+    setup_stats_timer();
+    return stats_xml();
+   } else if (command == "pdf") {
+    std::string id {xml.get<std::string>("request.id")};
+    validate_id(id);
+    Reichwein::Tempfile mdFilePath{".md"};
+    Reichwein::File::setFile(mdFilePath.getPath(), m_storage.getDocument(id));
+    Reichwein::Tempfile pdfFilePath{".pdf"};
+    int system_result{bp::system("/usr/bin/pandoc", mdFilePath.getPath().generic_string(), "-o", pdfFilePath.getPath().generic_string())};
+    if (system_result)
+     throw std::runtime_error("pandoc returned: "s + std::to_string(system_result));
+    std::string pdfdata{Reichwein::File::getFile(pdfFilePath.getPath())};
+    return make_xml({{"type", "pdf"}, {"pdf", Reichwein::Base64::encode64(pdfdata)}});
+   } else {
+    throw std::runtime_error("Bad command: "s + command);
+   }
+
+  } catch (const std::exception& ex) {
+   return make_xml({{"type", "error"}, {"message", "Message handling error: "s + ex.what()}}); 
+  }
+ }
+private:
+ ConnectionRegistry& m_registry;
+ Storage& m_storage;
+ std::mutex& m_storage_mutex;
+ connection m_ws;
+ ConnectionRegistry::RegistryGuard m_connection_guard;
+
+ boost::beast::http::request_parser<boost::beast::http::string_body> m_parser;
+ boost::beast::http::request<boost::beast::http::string_body> m_req;
+ boost::beast::flat_buffer m_buffer;
+
+ std::shared_ptr<boost::asio::steady_timer> m_stats_timer{};
+};
+
+void Whiteboard::do_accept()
+{
+ // The new connection gets its own strand
+ m_acceptor->async_accept(boost::asio::make_strand(*m_ioc),
+      std::bind(&Whiteboard::on_accept, this, _1, _2));
+}
+
+void Whiteboard::on_accept(boost::system::error_code ec, boost::asio::ip::tcp::socket socket)
+{
+ if (ec) {
+  std::cerr << "Error on accept: " << ec.message() << std::endl;
+ } else {
+  if (m_registry.number_of_connections() >= m_config->getMaxConnections()) {
+   // limit reached
+   socket.close();
+  } else {
+   std::make_shared<session>(m_registry, *m_storage, m_storage_mutex, std::move(socket))->run();
+  }
+ }
+
+ do_accept();
+}
+
+// for long running connections, don't timeout them but touch associated ids
+// regularly, at cleanup time
+void Whiteboard::touch_all_connections()
+{
+ std::for_each(m_registry.begin(), m_registry.end(), [&](const std::pair<ConnectionRegistry::connection, std::string>& i)
+               {
+                m_storage->touchDocument(i.second);
+               });
+}
+
+// the actual main() for testability
+int Whiteboard::run(int argc, char* argv[])
+{
+ try {
+  bool flag_cleanup{};
+  fs::path configFile;
+
+  if (argc == 2) {
+   if (argv[1] == "-h"s || argv[1] == "-?"s) {
+    usage();
+    exit(0);
+   } else if (argv[1] == "-C"s) {
+    flag_cleanup = true;
+   }
+  } else if (argc == 3) {
+   if (argv[1] == "-c"s) {
+    configFile = argv[2];
+   }
+  }
+
+  if (configFile.empty())
+   m_config = std::make_unique<Config>();
+  else
+   m_config = std::make_unique<Config>(configFile);
+
+  m_storage = std::make_unique<Storage>(*m_config);
+
+  if (flag_cleanup) {
+   m_storage->cleanup();
+   exit(0);
+  }
+
+  QRCode::init();
+
+  auto const address = boost::asio::ip::make_address(m_config->getListenAddress());
+  auto const port = static_cast<unsigned short>(m_config->getListenPort());
+
+  // The io_context is required for all I/O
+  m_ioc = std::make_unique<boost::asio::io_context>(m_config->getThreads());
+
+  // for now, just terminate on SIGINT, SIGHUP and SIGTERM
+  boost::asio::signal_set signals(*m_ioc, SIGINT, SIGTERM, SIGHUP);
+  signals.async_wait([&](const boost::system::error_code& error, int signal_number){
+                     std::cout << "Terminating via signal " << signal_number << std::endl;
+                     m_ioc->stop();
+                     });
+
+  // Storage cleanup once a day
+  boost::asio::steady_timer storage_cleanup_timer(*m_ioc, boost::asio::chrono::hours(24));
+  std::function<void(const boost::system::error_code&)> storage_cleanup_callback =
+    [&](const boost::system::error_code& error){
+          std::lock_guard<std::mutex> lock(m_storage_mutex);
+          if (!m_storage)
+           throw std::runtime_error("Storage not initialized");
+          touch_all_connections();
+          m_storage->cleanup();
+          storage_cleanup_timer.expires_at(storage_cleanup_timer.expires_at() + boost::asio::chrono::hours(24));
+          storage_cleanup_timer.async_wait(storage_cleanup_callback);
+    };
+  storage_cleanup_timer.async_wait(storage_cleanup_callback);
+
+  // The acceptor receives incoming connections
+  m_acceptor = std::make_unique<boost::asio::ip::tcp::acceptor>(*m_ioc, boost::asio::ip::tcp::endpoint{address, port});
+
+  do_accept();
+
+  // Run the I/O service on the requested number of threads
+  std::vector<std::thread> v;
+  v.reserve(m_config->getThreads() - 1);
+  for (auto i = m_config->getThreads() - 1; i > 0; --i) {
+   v.emplace_back(
+   [&]
+   {
+    m_ioc->run();
+   });
+  }
+  m_ioc->run();
+
+  for (auto& t: v) {
+   t.join();
+  }
+
+ } catch (const std::exception& ex) {
+  std::cerr << "Error: " << ex.what() << std::endl;
+ }
+
+ return 0;
+}
+
diff --git a/whiteboard.h b/whiteboard.h
new file mode 100644
index 0000000..53036ac
--- /dev/null
+++ b/whiteboard.h
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <filesystem>
+#include <memory>
+#include <mutex>
+#include <string>
+
+#include <boost/asio/ip/tcp.hpp>
+
+#include "diff.h"
+#include "config.h"
+#include "connectionregistry.h"
+#include "storage.h"
+
+class Whiteboard
+{
+public:
+ Whiteboard();
+ int run(int argc, char* argv[]);
+
+private:
+ std::unique_ptr<Config> m_config;
+ std::unique_ptr<Storage> m_storage;
+ std::mutex m_storage_mutex;
+
+ ConnectionRegistry m_registry;
+ 
+ std::unique_ptr<boost::asio::io_context> m_ioc;
+ std::unique_ptr<boost::asio::ip::tcp::acceptor> m_acceptor;
+
+ void do_accept();
+ void on_accept(boost::system::error_code ec, boost::asio::ip::tcp::socket socket);
+ void touch_all_connections();
+};
+