From 095c82585f2e4a9963c33c0988d453b0278bc0c7 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Tue, 28 Apr 2020 19:00:17 +0200
Subject: Paged list

---
 plugins/weblog/weblog.cpp | 101 +++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 15 deletions(-)

(limited to 'plugins/weblog/weblog.cpp')

diff --git a/plugins/weblog/weblog.cpp b/plugins/weblog/weblog.cpp
index 07b6447..a69fdb6 100644
--- a/plugins/weblog/weblog.cpp
+++ b/plugins/weblog/weblog.cpp
@@ -1,5 +1,7 @@
 #include "weblog.h"
 
+#include "stringutil.h"
+
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/property_tree/ptree.hpp>
@@ -152,7 +154,7 @@ namespace {
   }
  }
 
- std::vector<ArticleInfo> getArticleList(fs::path& path)
+ std::vector<ArticleInfo> getArticleList(fs::path& path, size_t page)
  {
   std::vector<ArticleInfo> result;
 
@@ -166,11 +168,12 @@ namespace {
    }
   }
 
-  size_t size{std::min(number_of_articles_on_front_page, result.size())};
+  size_t index0{std::min(number_of_articles_on_front_page * (page), result.size())};
+  size_t index1{std::min(number_of_articles_on_front_page * (page + 1), result.size())};
   // sort backwards
-  std::partial_sort(result.begin(), result.begin() + size, result.end(), [](const ArticleInfo& a0, const ArticleInfo& a1){ return a0.date > a1.date;});
+  std::partial_sort(result.begin(), result.begin() + index1, result.end(), [](const ArticleInfo& a0, const ArticleInfo& a1){ return a0.date > a1.date;});
   
-  return {result.begin(), result.begin() + size};
+  return {result.begin() + index0, result.begin() + index1};
  }
 
  std::string plainTextFromPTree(const pt::ptree& tree)
@@ -271,25 +274,35 @@ namespace {
 
  std::string generateIndexPage(fs::path& path,
                                std::function<std::string(const std::string& key)>& GetRequestParam,
-                               std::function<plugin_interface_setter_type>& SetResponseHeader)
+                               std::function<plugin_interface_setter_type>& SetResponseHeader,
+                               size_t page)
  {
   try {
    HtmlPage htmlPage{GetRequestParam, "<h1>"s + GetRequestParam("WEBLOG_NAME") + "</h1>"s};
 
    fs::path link{ GetRequestParam("rel_target")};
    
-   auto list{getArticleList(path)};
+   auto list{getArticleList(path, page)};
    if (list.empty())
     htmlPage += "(no articles found.)";
-   for (const auto& article: list) {
-    std::string linkstart{"<a href=\"" + (link / article.path.filename()).string() + "/\">"};
-    std::string linkend{"</a>"};
-    htmlPage += "<h2>"s + linkstart + article.subject + linkend + "</h2>"s + article.date + "<br/>"s;
-    
-    auto sv{shortVersion(article.path)};
-    if (sv.size()) {
-     htmlPage += sv + " "s + linkstart + "more..." + linkend;
+   else {
+    for (const auto& article: list) {
+     std::string linkstart{"<a href=\"" + (link / article.path.filename()).string() + "/\">"};
+     std::string linkend{"</a>"};
+     htmlPage += "<h2>"s + linkstart + article.subject + linkend + "</h2>"s + article.date + "<br/>"s;
+     
+     auto sv{shortVersion(article.path)};
+     if (sv.size()) {
+      htmlPage += sv + " "s + linkstart + "more..." + linkend;
+     }
     }
+    htmlPage += "<br/><br/><br/>";
+    if (page > 0)
+     htmlPage += "<a href=\"?page="s + std::to_string(page - 1) + "\">&lt;&lt;newer</a> "s;
+    htmlPage += "page "s + std::to_string(page + 1);
+    if (list.size() == number_of_articles_on_front_page)
+     htmlPage += " <a href=\"?page="s + std::to_string(page + 1) + "\">older&gt;&gt;</a>"s;
+    htmlPage += "<br/>";
    }
    return htmlPage;
   } catch (const std::exception& ex) {
@@ -334,6 +347,56 @@ namespace {
   }
  }
 
+ std::string urlDecode(std::string s)
+ {
+  std::string result;
+
+  size_t pos = 0;
+  while (pos < s.size()) {
+   char c {s[pos]};
+   if (c == '+') {
+    result += ' ';
+   } else if (c == '%' && pos + 2 < s.size()) {
+    try {
+     int i = stoi(s.substr(pos + 1, 2), 0, 16);
+     if (i < 0 || i > 255)
+      return result;
+
+     result += static_cast<char>(i);
+    } catch (...) {
+     return result;
+    }
+
+    pos += 2;
+   } else {
+    result += c;
+   }
+   pos++;
+  }
+
+  return result;
+ }
+
+ std::unordered_map<std::string, std::string> SplitQueryString(std::string& s)
+ {
+  std::unordered_map<std::string, std::string> result;
+
+  size_t qpos = s.find('?');
+  if (qpos != s.npos) {
+   auto list {split(s.substr(qpos + 1), "&")};
+   for (auto i: list) {
+    size_t apos = i.find('=');
+    if (apos != i.npos) {
+     result[urlDecode(i.substr(0, apos))] = urlDecode(i.substr(apos + 1));
+    }
+   }
+  }
+
+  s = s.substr(0, qpos);
+  
+  return result;
+ }
+
 } // anonymous namespace
 
 std::string weblog_plugin::name()
@@ -370,6 +433,8 @@ std::string weblog_plugin::generate_page(
    return HttpStatus("400", "Illegal request: "s + target, SetResponseHeader);
   }
 
+  std::unordered_map<std::string, std::string> query { SplitQueryString(rel_target) };
+
   // Build the path to the requested file
   std::string doc_root{GetRequestParam("doc_root")};
   if (rel_target.size() >= 4 && std::all_of(rel_target.begin(), rel_target.begin() + 4, isdigit)) {
@@ -384,8 +449,14 @@ std::string weblog_plugin::generate_page(
   
   SetResponseHeader("content_type", "text/html");
   
+  size_t page {0};
+  auto it {query.find("page")};
+  if (it != query.end()) {
+   page = stoul(it->second);
+  }
+
   if (is_index_page(rel_target))
-   return generateIndexPage(path, GetRequestParam, SetResponseHeader);
+   return generateIndexPage(path, GetRequestParam, SetResponseHeader, page);
 
   if (is_article_page(rel_target, path))
    return generateArticlePage(path, GetRequestParam, SetResponseHeader);
-- 
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