supports retry for web seeds that respond with 503

examples/client_test.cpp

@@ -542,6 +542,7 @@ int main(int ac, char* av[])
 	std::string proxy_login;
 	std::string proxy_type;
 	int poll_interval;
+	int wait_retry;
 
 	namespace po = boost::program_options;
 	try
@@ -582,6 +583,9 @@ int main(int ac, char* av[])
 		("poll-interval,t", po::value<int>(&poll_interval)->default_value(2)
 			, "if a directory is being monitored, this is the interval (given "
 			"in seconds) between two refreshes of the directory listing")
+		("wait-retry,w", po::value<int>(&wait_retry)->default_value(30)
+			, "if the download of a url seed failes, this is the interval (given "
+			"in seconds) to wait until the next retry")
 		("half-open-limit,o", po::value<int>(&half_open_limit)->default_value(-1)
 			, "Sets the maximum number of simultaneous half-open tcp connections")
 		("bind,b", po::value<std::string>(&bind_to_interface)->default_value("")
@@ -615,6 +619,7 @@ int main(int ac, char* av[])
 		if (download_limit <= 0) download_limit = -1;
 		if (upload_limit <= 0) upload_limit = -1;
 		if (poll_interval < 2) poll_interval = 2;
+		if (wait_retry < 0) wait_retry = 0;
 		if (half_open_limit < 1) half_open_limit = -1;
 		if (upload_slots_limit <= 0) upload_slots_limit = -1;
 		if (!monitor_dir.empty() && !exists(monitor_dir))
@@ -681,6 +686,7 @@ int main(int ac, char* av[])
 		}
 
 		settings.user_agent = "client_test/" LIBTORRENT_VERSION;
+		settings.urlseed_wait_retry = wait_retry;
 
 		std::deque<std::string> events;
 

include/libtorrent/session_settings.hpp

@@ -95,6 +95,7 @@ namespace libtorrent
 			, peer_timeout(120)
 			, urlseed_timeout(20)
 			, urlseed_pipeline_size(5)
+			, urlseed_wait_retry(30)
 			, file_pool_size(40)
 			, allow_multiple_connections_per_ip(false)
 			, max_failcount(3)
@@ -185,6 +186,9 @@ namespace libtorrent
 		
 		// controls the pipelining size of url-seeds
 		int urlseed_pipeline_size;
+
+		// time to wait until a new retry takes place
+		int urlseed_wait_retry;
 		
 		// sets the upper limit on the total number of files this
 		// session will keep open. The reason why files are

include/libtorrent/torrent.hpp

@@ -254,6 +254,8 @@ namespace libtorrent
 		void remove_url_seed(std::string const& url)
 		{ m_web_seeds.erase(url); }
 
+		void retry_url_seed(std::string const& url);
+
 		std::set<std::string> url_seeds() const
 		{ return m_web_seeds; }
 
@@ -626,6 +628,10 @@ namespace libtorrent
 		// The list of web seeds in this torrent. Seeds
 		// with fatal errors are removed from the set
 		std::set<std::string> m_web_seeds;
+
+		// a list of web seeds that have failed and are
+		// waiting to be retried
+		std::map<std::string, ptime> m_web_seeds_next_retry;
 		
 		// urls of the web seeds that we are currently
 		// resolving the address for

src/torrent.cpp

@@ -2857,6 +2857,18 @@ namespace libtorrent
 		// if we have everything we want we don't need to connect to any web-seed
 		if (!is_finished() && !m_web_seeds.empty())
 		{
+			// re-insert urls that are to be retries into the m_web_seeds
+			typedef std::map<std::string, ptime>::iterator iter_t;
+			for (iter_t i = m_web_seeds_next_retry.begin(); i != m_web_seeds_next_retry.end();)
+			{
+				iter_t erase_element = i++;
+				if (erase_element->second <= time_now())
+				{
+					m_web_seeds.insert(erase_element->first);
+					m_web_seeds_next_retry.erase(erase_element);
+				}
+			}
+
 			// keep trying web-seeds if there are any
 			// first find out which web seeds we are connected to
 			std::set<std::string> web_seeds;
@@ -2916,6 +2928,12 @@ namespace libtorrent
 		}
 	}
 
+	void torrent::retry_url_seed(std::string const& url)
+	{
+		m_web_seeds_next_retry[url] = time_now()
+			+ seconds(m_ses.settings().urlseed_wait_retry);
+	}
+
 	bool torrent::try_connect_peer()
 	{
 		TORRENT_ASSERT(want_more_peers());

src/web_peer_connection.cpp

@@ -360,7 +360,11 @@ namespace libtorrent
 					&& !(m_parser.status_code() >= 300 // redirect
 						&& m_parser.status_code() < 400))
 				{
-					// we should not try this server again.
+					if (m_parser.status_code() == 503)
+					{
+						// temporarily unavailable, retry later
+						t->retry_url_seed(m_url);
+					}
 					t->remove_url_seed(m_url);
 					std::string error_msg = boost::lexical_cast<std::string>(m_parser.status_code())
 						+ " " + m_parser.message();