Refactored scraper code to support multiple requests, even multiple requests mixed between scrapers.

CMakeLists.txt

@@ -1,5 +1,7 @@
 cmake_minimum_required(VERSION 2.6)
 
+INCLUDE(CPack)
+
 project(emulationstation)
 
 #-------------------------------------------------------------------------------

src/Settings.cpp

@@ -3,7 +3,6 @@
 #include "pugiXML/pugixml.hpp"
 #include "platform.h"
 #include <boost/filesystem.hpp>
-#include "scrapers/GamesDBScraper.h"
 
 Settings* Settings::sInstance = NULL;
 
@@ -50,8 +49,7 @@ void Settings::setDefaults()
 	mStringMap["TransitionStyle"] = "fade";
 	mStringMap["ThemeSet"] = "";
 	mStringMap["ScreenSaverBehavior"] = "dim";
-
+	mStringMap["Scraper"] = "TheGamesDB";
-	mScraper = std::shared_ptr<Scraper>(new GamesDBScraper());
 }
 
 template <typename K, typename V>
@@ -83,9 +81,6 @@ void Settings::saveFile()
 		node.append_attribute("value").set_value(iter->second.c_str());
 	}
 
-	pugi::xml_node scraperNode = doc.append_child("scraper");
-	scraperNode.append_attribute("value").set_value(mScraper->getName());
-
 	doc.save_file(path.c_str());
 }
 
@@ -112,23 +107,6 @@ void Settings::loadFile()
 		setFloat(node.attribute("name").as_string(), node.attribute("value").as_float());
 	for(pugi::xml_node node = doc.child("string"); node; node = node.next_sibling("string"))
 		setString(node.attribute("name").as_string(), node.attribute("value").as_string());
-
-	if(doc.child("scraper"))
-	{
-		std::shared_ptr<Scraper> scr = createScraperByName(doc.child("scraper").attribute("value").as_string());
-		if(scr)
-			mScraper = scr;
-	}
-}
-
-std::shared_ptr<Scraper> Settings::getScraper()
-{
-	return mScraper;
-}
-
-void Settings::setScraper(std::shared_ptr<Scraper> scraper)
-{
-	mScraper = scraper;
 }
 
 //Print a warning message if the setting we're trying to get doesn't already exist in the map, then return the value in the map.

src/Settings.h

@@ -1,9 +1,6 @@
-#ifndef _SETTINGS_H_
+#pragma once
-#define _SETTINGS_H_
-
 #include <string>
 #include <map>
-#include "scrapers/Scraper.h"
 
 //This is a singleton for storing settings.
 class Settings
@@ -25,9 +22,6 @@ public:
 	void setFloat(const std::string& name, float value);
 	void setString(const std::string& name, const std::string& value);
 
-	std::shared_ptr<Scraper> getScraper();
-	void setScraper(std::shared_ptr<Scraper> scraper);
-
 private:
 	static Settings* sInstance;
 
@@ -41,8 +35,5 @@ private:
 	std::map<std::string, float> mFloatMap;
 	std::map<std::string, std::string> mStringMap;
 
-	std::shared_ptr<Scraper> mScraper;
 	std::string mHomePathOverride;
 };
-
-#endif

src/components/ScraperSearchComponent.cpp

@@ -212,7 +212,7 @@ void ScraperSearchComponent::search(const ScraperSearchParams& params)
 	updateInfoPane();
 
 	mLastSearch = params;
-	mSearchHandle = Settings::getInstance()->getScraper()->getResultsAsync(params);
+	mSearchHandle = startScraperSearch(params);
 }
 
 void ScraperSearchComponent::stop()

src/guis/GuiMenu.cpp

@@ -38,16 +38,13 @@ GuiMenu::GuiMenu(Window* window) : GuiComponent(window), mMenu(window, "MAIN MEN
 			auto s = new GuiSettings(mWindow, "SCRAPER");
 
 			// scrape from
-			auto scraper_list = std::make_shared< OptionListComponent< std::shared_ptr<Scraper> > >(mWindow, "SCRAPE FROM", false);
+			auto scraper_list = std::make_shared< OptionListComponent< std::string > >(mWindow, "SCRAPE FROM", false);
-			std::vector< std::shared_ptr<Scraper> > scrapers;
+			std::vector<std::string> scrapers = getScraperList();
-			scrapers.push_back(std::make_shared<GamesDBScraper>());
-			scrapers.push_back(std::make_shared<TheArchiveScraper>());
-
 			for(auto it = scrapers.begin(); it != scrapers.end(); it++)
-				scraper_list->add((*it)->getName(), *it, (*it)->getName() == Settings::getInstance()->getScraper()->getName());
+				scraper_list->add(*it, *it, *it == Settings::getInstance()->getString("Scraper"));
 
 			s->addWithLabel("SCRAPE FROM", scraper_list);
-			s->addSaveFunc([scraper_list] { Settings::getInstance()->setScraper(scraper_list->getSelected()); });
+			s->addSaveFunc([scraper_list] { Settings::getInstance()->setString("Scraper", scraper_list->getSelected()); });
 
 			// scrape ratings
 			auto scrape_ratings = std::make_shared<SwitchComponent>(mWindow);

src/guis/GuiSettings.cpp

@@ -1,4 +1,5 @@
 #include "GuiSettings.h"
+#include "../Window.h"
 #include "../Settings.h"
 #include "../views/ViewController.h"
 

src/scrapers/GamesDBScraper.cpp

@@ -1,14 +1,12 @@
 #include "GamesDBScraper.h"
 #include "../components/ScraperSearchComponent.h"
-#include "../components/AsyncReqComponent.h"
+#include "Scraper.h"
 #include "../Log.h"
 #include "../pugiXML/pugixml.hpp"
 #include "../MetaData.h"
 #include "../Settings.h"
 #include <boost/assign.hpp>
 
-const char* GamesDBScraper::getName() { return "TheGamesDB"; }
-
 using namespace PlatformIds;
 const std::map<PlatformId, const char*> gamesdb_platformid_map = boost::assign::map_list_of
 	(THREEDO, "3DO")
@@ -61,9 +59,10 @@ const std::map<PlatformId, const char*> gamesdb_platformid_map = boost::assign::
 	(ZX_SPECTRUM, "Sinclair ZX Spectrum");
 
 
-std::unique_ptr<ScraperSearchHandle> GamesDBScraper::getResultsAsync(const ScraperSearchParams& params)
+void thegamesdb_generate_scraper_requests(const ScraperSearchParams& params, std::queue< std::unique_ptr<ScraperRequest> >& requests, 
+	std::vector<ScraperSearchResult>& results)
 {
-	std::string path = "/api/GetGame.php?";
+	std::string path = "thegamesdb.net/api/GetGame.php?";
 
 	std::string cleanName = params.nameOverride;
 	if(cleanName.empty())
@@ -78,48 +77,24 @@ std::unique_ptr<ScraperSearchHandle> GamesDBScraper::getResultsAsync(const Scrap
 		{
 			path += "&platform=";
 			path += HttpReq::urlEncode(platformIt->second);
-		}else{
+		}
+		else{
 			LOG(LogWarning) << "TheGamesDB scraper warning - no support for platform " << getPlatformName(params.system->getPlatformId());
 		}
 	}
 
-	path = "thegamesdb.net" + path;
+	requests.push(std::unique_ptr<ScraperRequest>(new ScraperHttpRequest(results, path, &thegamesdb_process_httpreq)));
-
-	return std::unique_ptr<ScraperSearchHandle>(new GamesDBHandle(params, path));
 }
 
-GamesDBHandle::GamesDBHandle(const ScraperSearchParams& params, const std::string& url) : 
+void thegamesdb_process_httpreq(const std::unique_ptr<HttpReq>& req, std::vector<ScraperSearchResult>& results)
-	mReq(std::unique_ptr<HttpReq>(new HttpReq(url)))
 {
-	setStatus(ASYNC_IN_PROGRESS);
+	assert(req->status() == HttpReq::REQ_SUCCESS);
-}
-
-void GamesDBHandle::update()
-{
-	if(mStatus == ASYNC_DONE)
-		return;
-
-	if(mReq->status() == HttpReq::REQ_IN_PROGRESS)
-		return;
-
-	if(mReq->status() != HttpReq::REQ_SUCCESS)
-	{
-		std::stringstream ss;
-		ss << "Network error - " << mReq->getErrorMsg();
-		setError(ss.str());
-		return;
-	}
-
-	// our HTTP request was successful
-	// try to build our result list
-
-	std::vector<ScraperSearchResult> results;
 
 	pugi::xml_document doc;
-	pugi::xml_parse_result parseResult = doc.load(mReq->getContent().c_str());
+	pugi::xml_parse_result parseResult = doc.load(req->getContent().c_str());
 	if(!parseResult)
 	{
-		setError("Error parsing XML");
+		LOG(LogError) << "GamesDBRequest - Error parsing XML. \n\t" << parseResult.description() << "";
 		return;
 	}
 
@@ -127,9 +102,8 @@ void GamesDBHandle::update()
 
 	std::string baseImageUrl = data.child("baseImgUrl").text().get();
 
-	unsigned int resultNum = 0;
 	pugi::xml_node game = data.child("Game");
-	while(game && resultNum < MAX_SCRAPER_RESULTS)
+	while(game && results.size() < MAX_SCRAPER_RESULTS)
 	{
 		ScraperSearchResult result;
 
@@ -166,12 +140,6 @@ void GamesDBHandle::update()
 		}
 
 		results.push_back(result);
-
-		resultNum++;
 		game = game.next_sibling("Game");
 	}
-
-	setStatus(ASYNC_DONE);
-	setResults(results);
-	return;
 }

src/scrapers/GamesDBScraper.h

@@ -1,24 +1,8 @@
 #pragma once
 
 #include "Scraper.h"
-#include "../HttpReq.h"
 
-class GamesDBHandle : public ScraperSearchHandle
+void thegamesdb_generate_scraper_requests(const ScraperSearchParams& params, std::queue< std::unique_ptr<ScraperRequest> >& requests, 
-{
+	std::vector<ScraperSearchResult>& results);
-public:
-	GamesDBHandle(const ScraperSearchParams& params, const std::string& url);
 
-	void update() override;
+void thegamesdb_process_httpreq(const std::unique_ptr<HttpReq>& req, std::vector<ScraperSearchResult>& results);
-
-private:
-	std::unique_ptr<HttpReq> mReq;
-	ScraperSearchParams mParams;
-};
-
-class GamesDBScraper : public Scraper
-{
-public:
-	std::unique_ptr<ScraperSearchHandle> getResultsAsync(const ScraperSearchParams& params) override;
-
-	const char* getName();
-};

src/scrapers/Scraper.cpp

@@ -4,21 +4,90 @@
 #include "../Settings.h"
 #include <FreeImage.h>
 #include <boost/filesystem.hpp>
-#include <boost/regex.hpp>
+#include <boost/assign.hpp>
 
 #include "GamesDBScraper.h"
 #include "TheArchiveScraper.h"
 
-std::shared_ptr<Scraper> createScraperByName(const std::string& name)
+const std::map<std::string, generate_scraper_requests_func> scraper_request_funcs = boost::assign::map_list_of
-{
+	("TheGamesDB", &thegamesdb_generate_scraper_requests)
-	if(name == "TheGamesDB")
+	("TheArchive", &thearchive_generate_scraper_requests);
-		return std::shared_ptr<Scraper>(new GamesDBScraper());
-	else if(name == "TheArchive")
-		return std::shared_ptr<Scraper>(new TheArchiveScraper());
 
-	return nullptr;
+std::unique_ptr<ScraperSearchHandle> startScraperSearch(const ScraperSearchParams& params)
+{
+	const std::string& name = Settings::getInstance()->getString("Scraper");
+
+	std::unique_ptr<ScraperSearchHandle> handle(new ScraperSearchHandle());
+	scraper_request_funcs.at(name)(params, handle->mRequestQueue, handle->mResults);
+	return handle;
 }
 
+std::vector<std::string> getScraperList()
+{
+	std::vector<std::string> list;
+	for(auto it = scraper_request_funcs.begin(); it != scraper_request_funcs.end(); it++)
+	{
+		list.push_back(it->first);
+	}
+
+	return list;
+}
+
+// ScraperSearchHandle
+ScraperSearchHandle::ScraperSearchHandle()
+{
+	setStatus(ASYNC_IN_PROGRESS);
+}
+
+void ScraperSearchHandle::update()
+{
+	if(mStatus == ASYNC_DONE)
+		return;
+
+	while(!mRequestQueue.empty() && mRequestQueue.front()->update())
+		mRequestQueue.pop();
+
+	if(mRequestQueue.empty())
+	{
+		setStatus(ASYNC_DONE);
+		return;
+	}
+}
+
+
+
+// ScraperRequest
+ScraperRequest::ScraperRequest(std::vector<ScraperSearchResult>& resultsWrite) : mResults(resultsWrite)
+{
+}
+
+
+// ScraperHttpRequest
+ScraperHttpRequest::ScraperHttpRequest(std::vector<ScraperSearchResult>& resultsWrite, const std::string& url, scraper_process_httpreq processFunc) 
+	: ScraperRequest(resultsWrite), mProcessFunc(processFunc)
+{
+	mReq = std::unique_ptr<HttpReq>(new HttpReq(url));
+}
+
+bool ScraperHttpRequest::update()
+{
+	if(mReq->status() == HttpReq::REQ_SUCCESS)
+	{
+		mProcessFunc(mReq, mResults);
+		return true;
+	}
+
+	if(mReq->status() == HttpReq::REQ_IN_PROGRESS)
+		return false;
+
+	// everything else is some sort of error
+	LOG(LogError) << "ScraperHttpRequest network error - " << mReq->getErrorMsg();
+	return true;
+}
+
+
+// metadata resolving stuff
+
 std::unique_ptr<MDResolveHandle> resolveMetaDataAssets(const ScraperSearchResult& result, const ScraperSearchParams& search)
 {
 	return std::unique_ptr<MDResolveHandle>(new MDResolveHandle(result, search));

src/scrapers/Scraper.h

@@ -6,6 +6,7 @@
 #include "../AsyncHandle.h"
 #include <vector>
 #include <functional>
+#include <queue>
 
 struct ScraperSearchParams
 {
@@ -24,29 +25,87 @@ struct ScraperSearchResult
 	std::string thumbnailUrl;
 };
 
+// So let me explain why I've abstracted this so heavily.
+// There are two ways I can think of that you'd want to write a scraper.
+
+// 1. Do some HTTP request(s) -> process it -> return the results
+// 2. Do some local filesystem queries (an offline scraper) -> return the results
+
+// The first way needs to be asynchronous while it's waiting for the HTTP request to return.
+// The second doesn't.
+
+// It would be nice if we could write it like this:
+// search = generate_http_request(searchparams);
+// wait_until_done(search);
+// ... process search ...
+// return results;
+
+// We could do this if we used threads.  Right now ES doesn't because I'm pretty sure I'll fuck it up,
+// and I'm not sure of the performance of threads on the Pi (single-core ARM).
+// We could also do this if we used coroutines.  
+// I can't find a really good cross-platform coroutine library (x86/64/ARM Linux + Windows), 
+// and I don't want to spend more time chasing libraries than just writing it the long way once.
+
+// So, I did it the "long" way.
+// ScraperSearchHandle - one logical search, e.g. "search for mario"
+// ScraperRequest - encapsulates some sort of asynchronous request that will ultimately return some results
+// ScraperHttpRequest - implementation of ScraperRequest that waits on an HttpReq, then processes it with some processing function.
+
+
+// a scraper search gathers results from (potentially multiple) ScraperRequests
+class ScraperRequest
+{
+public:
+	ScraperRequest(std::vector<ScraperSearchResult>& resultsWrite);
+
+	// returns "true" once we're done
+	virtual bool update() = 0;
+
+protected:
+	std::vector<ScraperSearchResult>& mResults;
+};
+
+
+typedef void (*scraper_process_httpreq)(const std::unique_ptr<HttpReq>& req, std::vector<ScraperSearchResult>& results);
+
+// a single HTTP request that needs to be processed to get the results
+class ScraperHttpRequest : ScraperRequest
+{
+public:
+	ScraperHttpRequest(std::vector<ScraperSearchResult>& resultsWrite, const std::string& url, scraper_process_httpreq processFunc);
+	bool update() override;
+
+private:
+	scraper_process_httpreq mProcessFunc;
+	std::unique_ptr<HttpReq> mReq;
+};
+
+// a request to get a list of results
 class ScraperSearchHandle : public AsyncHandle
 {
 public:
-	virtual void update() = 0;
+	ScraperSearchHandle();
+
+	void update();
 	inline const std::vector<ScraperSearchResult>& getResults() const { assert(mStatus != ASYNC_IN_PROGRESS); return mResults; }
 
 protected:
-	inline void setResults(const std::vector<ScraperSearchResult>& results) { mResults = results; }
+	friend std::unique_ptr<ScraperSearchHandle> startScraperSearch(const ScraperSearchParams& params);
 
-private:
+	std::queue< std::unique_ptr<ScraperRequest> > mRequestQueue;
 	std::vector<ScraperSearchResult> mResults;
 };
 
-class Scraper
+// will use the current scraper settings to pick the result source
-{
+std::unique_ptr<ScraperSearchHandle> startScraperSearch(const ScraperSearchParams& params);
-public:
-	//Get a list of potential results.
-	virtual std::unique_ptr<ScraperSearchHandle> getResultsAsync(const ScraperSearchParams& params) = 0;
 
-	virtual const char* getName() = 0;
+// returns a list of valid scraper names
-};
+std::vector<std::string> getScraperList();
+
+typedef void (*generate_scraper_requests_func)(const ScraperSearchParams& params, std::queue< std::unique_ptr<ScraperRequest> >& requests, std::vector<ScraperSearchResult>& results);
+
+// -------------------------------------------------------------------------
 
-std::shared_ptr<Scraper> createScraperByName(const std::string& name);
 
 
 // Meta data asset downloading stuff.

src/scrapers/TheArchiveScraper.cpp

@@ -4,11 +4,10 @@
 #include "../Log.h"
 #include "../pugiXML/pugixml.hpp"
 
-const char* TheArchiveScraper::getName() { return "TheArchive"; }
+void thearchive_generate_scraper_requests(const ScraperSearchParams& params, std::queue< std::unique_ptr<ScraperRequest> >& requests,
-
+	std::vector<ScraperSearchResult>& results)
-std::unique_ptr<ScraperSearchHandle> TheArchiveScraper::getResultsAsync(const ScraperSearchParams& params)
 {
-	std::string path = "/2.0/Archive.search/xml/7TTRM4MNTIKR2NNAGASURHJOZJ3QXQC5/";
+	std::string path = "api.archive.vg/2.0/Archive.search/xml/7TTRM4MNTIKR2NNAGASURHJOZJ3QXQC5/";
 
 	std::string cleanName = params.nameOverride;
 	if(cleanName.empty())
@@ -17,51 +16,25 @@ std::unique_ptr<ScraperSearchHandle> TheArchiveScraper::getResultsAsync(const Sc
 	path += HttpReq::urlEncode(cleanName);
 	//platform TODO, should use some params.system get method
 
-	path = "api.archive.vg" + path;
+	requests.push(std::unique_ptr<ScraperRequest>(new ScraperHttpRequest(results, path, &thearchive_process_httpreq)));
-
-	return std::unique_ptr<ScraperSearchHandle>(new TheArchiveHandle(params, path));
 }
 
-TheArchiveHandle::TheArchiveHandle(const ScraperSearchParams& params, const std::string& url) : 
+void thearchive_process_httpreq(const std::unique_ptr<HttpReq>& req, std::vector<ScraperSearchResult>& results)
-	mReq(std::unique_ptr<HttpReq>(new HttpReq(url)))
 {
-	setStatus(ASYNC_IN_PROGRESS);
+	assert(req->status() == HttpReq::REQ_SUCCESS);
-}
-
-void TheArchiveHandle::update()
-{
-	if(mStatus == ASYNC_DONE)
-		return;
-
-	if(mReq->status() == HttpReq::REQ_IN_PROGRESS)
-		return;
-
-	if(mReq->status() != HttpReq::REQ_SUCCESS)
-	{
-		std::stringstream ss;
-		ss << "Network error: " << mReq->getErrorMsg();
-		setError(ss.str());
-		return;
-	}
-
-	// if we're here, our HTTP request finished successfully
-	
-	// so, let's try building our result list
-	std::vector<ScraperSearchResult> results;
 
 	pugi::xml_document doc;
-	pugi::xml_parse_result parseResult = doc.load(mReq->getContent().c_str());
+	pugi::xml_parse_result parseResult = doc.load(req->getContent().c_str());
 	if(!parseResult)
 	{
-		setError("Error parsing XML");
+		LOG(LogError) << "TheArchiveRequest - error parsing XML.\n\t" << parseResult.description();
 		return;
 	}
 
 	pugi::xml_node data = doc.child("OpenSearchDescription").child("games");
 
-	unsigned int resultNum = 0;
 	pugi::xml_node game = data.child("game");
-	while(game && resultNum < MAX_SCRAPER_RESULTS)
+	while(game && results.size() < MAX_SCRAPER_RESULTS)
 	{
 		ScraperSearchResult result;
 
@@ -86,11 +59,6 @@ void TheArchiveHandle::update()
 			result.thumbnailUrl = thumbnail.text().get();
 
 		results.push_back(result);
-
-		resultNum++;
 		game = game.next_sibling("game");
 	}
-
-	setStatus(ASYNC_DONE);
-	setResults(results);
 }

src/scrapers/TheArchiveScraper.h

@@ -1,24 +1,8 @@
 #pragma once
 
 #include "Scraper.h"
-#include "../HttpReq.h"
 
-class TheArchiveHandle : public ScraperSearchHandle
+void thearchive_generate_scraper_requests(const ScraperSearchParams& params, std::queue< std::unique_ptr<ScraperRequest> >& requests,
-{
+	std::vector<ScraperSearchResult>& results);
-public:
-	TheArchiveHandle(const ScraperSearchParams& params, const std::string& url);
 
-	void update() override;
+void thearchive_process_httpreq(const std::unique_ptr<HttpReq>& req, std::vector<ScraperSearchResult>& results);
-
-private:
-	std::unique_ptr<HttpReq> mReq;
-	ScraperSearchParams mParams;
-};
-
-class TheArchiveScraper : public Scraper
-{
-public:
-	std::unique_ptr<ScraperSearchHandle> getResultsAsync(const ScraperSearchParams& params) override;
-
-	const char* getName();
-};