Save data on file backend

3 files changed, 130 insertions, 9 deletions

diff --git a/html/index.html b/html/index.html
index 64eae90..fdd56dc 100644
--- a/html/index.html
+++ b/html/index.html
@@ -14,6 +14,9 @@
                         <textarea rows="30" cols="80" id="board" name="board"></textarea>
 			<br/>
 			<br/>
+			<button class="button" onclick="on_new_page();">New page</button>
+			<br/>
+			<br/>
 			Reichwein.IT Whiteboard by <a href="https://www.reichwein.it">https://www.reichwein.it</a><br/>
 		</div>
 
diff --git a/html/whiteboard.js b/html/whiteboard.js
index 2b35180..9018f92 100644
--- a/html/whiteboard.js
+++ b/html/whiteboard.js
@@ -6,6 +6,12 @@ function init() {
 function init_board() {
 	var xhr = new XMLHttpRequest();
 	
+        const searchParams = (new URL(document.location)).searchParams;
+        if (!searchParams.has('id')) {
+                redirect_to_new_page();
+                return;
+        }
+
 	// run on data received back
 	xhr.onreadystatechange = function() {
 				if (this.readyState == 3) {
@@ -47,7 +53,7 @@ function init_board() {
 	requestElement.appendChild(commandElement);
 
 	var idElement = xmlDocument.createElement("id");
-	idElement.appendChild(document.createTextNode("id1"));
+	idElement.appendChild(document.createTextNode(get_id()));
 	requestElement.appendChild(idElement);
 
 	xhr.open("POST", "whiteboard.fcgi", true);
@@ -58,7 +64,65 @@ function init_board() {
 	//set_status("Please wait while server prepares " + filename + " ...");
 }
 
-function on_modify() {
+function get_id()
+{
+        const searchParams = (new URL(document.location)).searchParams;
+        return searchParams.get('id');
+}
+
+function on_new_page()
+{
+        redirect_to_new_page();
+}
+
+function redirect_to_new_page()
+{
+	var xhr = new XMLHttpRequest();
+	
+	// run on data received back
+	xhr.onreadystatechange = function() {
+				if (this.readyState == 3) {
+					//set_status("Please wait while downloading " + filename + " ...");
+					return;
+				}
+                                if (this.readyState != 4) {
+					return;
+				}
+				if (this.status != 200) {
+					//set_status("Server Error while retrieving " + filename + ", status: " + this.status + " " + this.statusText);
+                                        return;
+                                }
+
+                                var id = this.responseText;
+                                //alert("location=" + document.location.href);
+                                var new_location = document.location.href;
+                                var pos = new_location.search("\\?");
+                                if (pos >= 0)
+                                        new_location = new_location.substring(0, pos);
+                                new_location += '?id=' + id;
+
+                                window.location.href = new_location;
+				//set_status(""); // OK
+	}
+
+	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("newid"));
+	requestElement.appendChild(commandElement);
+
+	xhr.open("POST", "whiteboard.fcgi", true);
+	xhr.setRequestHeader("Content-type", "text/xml");
+	xhr.send(xmlDocument);
+
+	//set_status("Please wait while server prepares " + filename + " ...");
+}
+
+function on_modify()
+{
 	var xhr = new XMLHttpRequest();
 	
 	// run on data received back
@@ -88,7 +152,7 @@ function on_modify() {
 	requestElement.appendChild(commandElement);
 
 	var idElement = xmlDocument.createElement("id");
-	idElement.appendChild(document.createTextNode("id1"));
+	idElement.appendChild(document.createTextNode(get_id()));
 	requestElement.appendChild(idElement);
 
 	var dataElement = xmlDocument.createElement("data");
@@ -155,7 +219,7 @@ function checkupdate() {
 	requestElement.appendChild(commandElement);
 
 	var idElement = xmlDocument.createElement("id");
-	idElement.appendChild(document.createTextNode("id1"));
+	idElement.appendChild(document.createTextNode(get_id()));
 	requestElement.appendChild(idElement);
 
 	var checksumElement = xmlDocument.createElement("checksum");
diff --git a/whiteboard.cpp b/whiteboard.cpp
index b6b3a8d..09674b5 100644
--- a/whiteboard.cpp
+++ b/whiteboard.cpp
@@ -9,6 +9,7 @@
 #include <iostream>
 #include <functional>
 #include <filesystem>
+#include <random>
 #include <regex>
 #include <string>
 #include <unordered_map>
@@ -26,18 +27,65 @@ namespace fs = std::filesystem;
 
 namespace {
 
- uint32_t checksum32(const std::string& s) {
+ uint32_t checksum32(const std::string& s)
+ {
   uint32_t result{0};
   for (int i = 0; i < s.size(); i++) {
    result = ((result >> 1) | ((result & 1) << 31)) ^ (s[i] & 0xFF);
   }
   return result & 0x7FFFFFFF;
  }
+
+ std::string generate_id()
+ {
+  static std::random_device r;
+  static std::default_random_engine e1(r());
+  static std::uniform_int_distribution<int> uniform_dist(0, 15);
+
+  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' + 'a';
+   result.push_back(c);
+  }
+  return result;
+ }
+
+ fs::path data_path;
+
+ void setFileById(const std::string& data, const std::string& id)
+ {
+  fs::path path{data_path / id};
+ 
+  // skip if it doesn't exists 
+  if (data.empty() && !fs::exists(path))
+   return;
+
+  // clean up immediately, if appropriate
+  if (data.empty()) {
+   fs::remove(path);
+   return;
+  }
+
+  File::setFile(path, data);
+ }
+
+ std::string getFileById(const std::string& id)
+ {
+  fs::path path{data_path / id};
+
+  if (!fs::exists(path))
+   return {};
+
+  return File::getFile(path);
+ }
 }
 
 int main(void)
 {
  Config config;
+ data_path = config.getDataPath();
 
  int result = FCGX_Init();
  if (result != 0) { // error on init
@@ -58,8 +106,6 @@ int main(void)
   return 1;
  }
 
- std::string filedata {""}; // initial content
-
  while (FCGX_Accept_r(&request) >= 0) {
   try {
    char* method = FCGX_GetParam("REQUEST_METHOD", request.envp);
@@ -81,13 +127,16 @@ int main(void)
     pt::xml_parser::read_xml(ss, xml);
 
     std::string command {xml.get<std::string>("request.command")};
-    std::string id {xml.get<std::string>("request.id")};
 
     if (command == "modify") {
+     std::string id {xml.get<std::string>("request.id")};
      std::string data {xml.get<std::string>("request.data")};
-     filedata = data;
+     setFileById(data, id);
      FCGX_PutS("Content-Type: text/plain\r\n\r\n", request.out);
     } else if (command == "getfile") {
+     std::string id {xml.get<std::string>("request.id")};
+
+     std::string filedata {getFileById(id)};
 
      if (filedata.size() > 30000000)
       throw std::runtime_error("File too big");
@@ -96,12 +145,14 @@ int main(void)
      FCGX_FPrintF(request.out, "Content-Length: %d\r\n\r\n", filedata.size());
      FCGX_PutStr(filedata.c_str(), filedata.size(), request.out);
     } else if (command == "checkupdate") {
+     std::string id {xml.get<std::string>("request.id")};
      std::string checksum_s {xml.get<std::string>("request.checksum")};
      uint32_t checksum{static_cast<uint32_t>(stoul(checksum_s))};
 
      //std::cout << "Checksum JS: " << checksum_s << std::endl;
      //std::cout << "Checksum C++: " << checksum32(filedata) << std::endl;
 
+     std::string filedata {getFileById(id)};
      if (checksum != checksum32(filedata)) {
       //std::cout << "Sending change..." << std::endl;
       FCGX_PutS("Content-Type: application/octet-stream\r\n", request.out);
@@ -112,6 +163,9 @@ int main(void)
       FCGX_PutS("Content-Type: text/plain\r\n\r\n", request.out);
       FCGX_PutS("No change.\r\n", request.out);
      }
+    } else if (command == "newid") {
+     FCGX_PutS("Content-Type: text/plain\r\n\r\n", request.out);
+     FCGX_PutS(generate_id().c_str(), request.out);
     } else {
      throw std::runtime_error("Bad command: "s + command);
     }