adds rss feed support to blog

Src/AtomBuilder.cpp

@@ -0,0 +1,70 @@
+#include "AtomBuilder.h"
+
+AtomBuilder::AtomBuilder(std::string templateUrl)
+{
+    feed = readFile(templateUrl);
+    int updateTagLocation = calculateStartOfIdentifierLocation(feed, "</updated>");
+    if (updateTagLocation == -1)
+        printf("unable to find header update tag in AtomFeedTemplate");
+    feed.insert(updateTagLocation, getTimeString());
+}
+
+std::string AtomBuilder::getTimeString()
+{
+    // taken from https://en.cppreference.com/w/cpp/chrono/c/strftime
+    std::time_t time = std::time({});
+    char timeString[std::size("yyyy-mm-ddThh:mm:ssZ")];
+    std::strftime(std::data(timeString), std::size(timeString),
+                  "%FT%TZ", std::gmtime(&time));
+    return timeString;
+}
+
+int AtomBuilder::calculateStartOfIdentifierLocation(std::string text, std::string id)
+{
+    int location = text.find(id);
+    if (location == std::string::npos)
+        printf("Warning: no article found in given template file");
+    return location;
+}
+
+std::string AtomBuilder::readFile(std::string fileUrl)
+{
+    std::ifstream file(fileUrl);
+    std::stringstream fileCache;
+    fileCache << file.rdbuf();
+
+    return fileCache.str();
+}
+
+std::string AtomBuilder::getFeedHeader(std::string title, std::string link, std::string timestamp)
+{
+    return  "<title>" + title + "</title>\n"
+            + "<link href=\"" + link + "\"/>\n"
+            + "<id>" + link + "</id>\n"
+            + "<updated>" + timestamp + "</updated>\n";
+}
+
+void AtomBuilder::addHTMLEntry(std::string article, std::string title, std::string link, std::string timestamp)
+{
+    int insertLocation = calculateStartOfIdentifierLocation(feed, "</feed>");
+
+    std::string buffer;
+    buffer += "<entry>\n";
+    buffer += getFeedHeader(title, link, timestamp);
+    buffer += "<content type=\"html\">\n<![CDATA[\n";
+    buffer += article;
+    buffer += "]]>\n</content>\n</entry>";
+    feed.insert(insertLocation, buffer);
+
+}
+
+void AtomBuilder::writeToFile(std::string outFolderUrl)
+{
+    outFolderUrl += "/feed.xml";
+    std::ofstream file(outFolderUrl);
+    file << feed;
+    file.close();
+
+    if (file.fail())
+        printf("failed to write file to %s \n", outFolderUrl.c_str());
+}