From 4854ea85f20266a80f807effb4542008c7087d5b Mon Sep 17 00:00:00 2001
From: Albert S <mail@quitesimple.org>
Date: Sun, 27 Mar 2022 19:48:57 +0200
Subject: [PATCH] Begin HandlerFeedGenerator: Generates Atom feeds for
 categories (or all pages)

---
 handlers/handlerfeedgenerator.cpp | 129 ++++++++++++++++++++++++++++++
 handlers/handlerfeedgenerator.h   |  21 +++++
 2 files changed, 150 insertions(+)
 create mode 100644 handlers/handlerfeedgenerator.cpp
 create mode 100644 handlers/handlerfeedgenerator.h

diff --git a/handlers/handlerfeedgenerator.cpp b/handlers/handlerfeedgenerator.cpp
new file mode 100644
index 0000000..c87a685
--- /dev/null
+++ b/handlers/handlerfeedgenerator.cpp
@@ -0,0 +1,129 @@
+#include "handlerfeedgenerator.h"
+#include "../parser.h"
+std::vector<HandlerFeedGenerator::EntryRevisionPair> HandlerFeedGenerator::fetchEntries(
+	std::vector<std::string> categories)
+{
+	auto revisionDao = this->database->createRevisionDao();
+	auto pageDao = this->database->createPageDao();
+
+	std::vector<EntryRevisionPair> result;
+	QueryOption option;
+	option.includeInvisible = false;
+	// option.limit = 20;
+	std::set<std::string> members;
+	if(categories.empty())
+	{
+		auto pages = pageDao->getPageList(option);
+		std::copy(pages.begin(), pages.end(), std::inserter(members, members.end()));
+	}
+	else
+	{
+		auto categoryDao = this->database->createCategoryDao();
+		for(std::string cat : categories)
+		{
+			auto catmembers = categoryDao->fetchMembers(cat, option);
+			std::copy(catmembers.begin(), catmembers.end(), std::inserter(members, members.end()));
+		}
+	}
+	for(const std::string &member : members)
+	{
+		auto page = pageDao->find(member).value();
+		auto revision = revisionDao->getRevisionForPage(page.name, 1).value();
+		result.push_back({page, revision});
+	}
+	std::sort(result.begin(), result.end(),
+			  [](EntryRevisionPair &a, EntryRevisionPair &b) { return a.second.timestamp > b.second.timestamp; });
+
+	const int maxResults = 20;
+	if(result.size() > maxResults)
+	{
+		result.erase(result.begin() + maxResults - 1, result.end());
+	}
+
+	return result;
+}
+
+Response HandlerFeedGenerator::generateAtom(const std::vector<HandlerFeedGenerator::EntryRevisionPair> &entries,
+											std::string filter)
+{
+
+	std::stringstream stream;
+	// don't care about offset for now especially since "%z" does not return what we need exactly (with ':')
+	const std::string dateformat = "%Y-%m-%dT%T";
+
+	time_t newestPublished = 0;
+	std::string atomfooter = this->templ->loadResolvedPart("feeds/atomfooter");
+	auto revisionDao = this->database->createRevisionDao();
+	auto pageDao = this->database->createPageDao();
+
+	if(utils::trim(filter).empty())
+	{
+		filter = "All pages";
+	}
+
+	for(const EntryRevisionPair &entry : entries)
+	{
+		const Page &page = entry.first;
+		const Revision &initialRevision = entry.second;
+		Revision current = revisionDao->getCurrentForPage(page.name).value();
+		std::string url = this->urlProvider->rootUrl() + this->urlProvider->page(page.name);
+		if(initialRevision.timestamp > newestPublished)
+		{
+			newestPublished = initialRevision.timestamp;
+		}
+		std::string entryPublished = utils::formatLocalDate(initialRevision.timestamp, dateformat) + "Z";
+		std::string entryurl =
+			this->urlProvider->combine({this->urlProvider->rootUrl(), this->urlProvider->page(page.name)});
+		TemplatePage atomentry = this->templ->getPage("feeds/atomentry");
+		atomentry.setVar("entrytitle", utils::html_xss(page.title));
+		atomentry.setVar("entryurl", utils::html_xss(entryurl));
+		atomentry.setVar("entryid", utils::html_xss(entryurl));
+		atomentry.setVar("entrypublished", entryPublished);
+		Parser parser;
+		atomentry.setVar("entrycontent", utils::html_xss(parser.parse(*pageDao, *this->urlProvider, current.content)));
+		stream << atomentry.render();
+	}
+	stream << atomfooter;
+	TemplatePage atomheader = this->templ->getPage("feeds/atomheader");
+	atomheader.setVar("subtitle", filter);
+	atomheader.setVar("atomfeeduniqueid", utils::html_xss(this->urlProvider->atomFeed(filter)));
+	atomheader.setVar("atomfeedupdate", utils::formatLocalDate(newestPublished, dateformat) + "Z");
+
+	Response result;
+	result.setStatus(200);
+	result.setContentType("application/atom+xml");
+	result.setBody(atomheader.render() + stream.str());
+	return result;
+}
+
+Response HandlerFeedGenerator::handleRequest(const Request &r)
+{
+	Response response;
+	try
+	{
+		std::string type = r.get("type");
+		std::string categories = r.get("cats");
+
+		auto entries = fetchEntries(utils::split(categories, ','));
+		if(type == "atom")
+		{
+			std::string filter = categories;
+			response = generateAtom(entries, filter);
+		}
+		else
+		{
+			return errorResponse("Invalid feed type", "Unknown feed type, try atom", 400);
+		}
+	}
+	catch(std::runtime_error &e)
+	{
+		Logger::error() << "Error while serving feed: " << e.what();
+		return errorResponse("Error", "An error occured while trying to serve the feed", 500);
+	}
+	return response;
+}
+
+bool HandlerFeedGenerator::canAccess(const Permissions &perms)
+{
+	return true;
+}
diff --git a/handlers/handlerfeedgenerator.h b/handlers/handlerfeedgenerator.h
new file mode 100644
index 0000000..5d803b0
--- /dev/null
+++ b/handlers/handlerfeedgenerator.h
@@ -0,0 +1,21 @@
+#ifndef HANDLERFEEDGENERATOR_H
+#define HANDLERFEEDGENERATOR_H
+#include "handler.h"
+#include "../page.h"
+#include "../revision.h"
+class HandlerFeedGenerator : public Handler
+{
+	typedef std::pair<Page, Revision> EntryRevisionPair;
+
+  protected:
+	std::vector<EntryRevisionPair> fetchEntries(std::vector<std::string> categories);
+	Response generateAtom(const std::vector<EntryRevisionPair> &entries, std::string atomtitle);
+	Response generateRss(const std::vector<EntryRevisionPair> &entries);
+
+  public:
+	using Handler::Handler;
+	Response handleRequest(const Request &r) override;
+	bool canAccess(const Permissions &perms) override;
+};
+
+#endif // HANDLERFEEDGENERATOR_H