support web seeds in magnet links

include/libtorrent/add_torrent_params.hpp

@@ -247,6 +247,9 @@ namespace libtorrent
 		// ``trackers`` can specify tracker URLs for the torrent.
 		std::vector<std::string> trackers;
 
+		// url seeds to be added to the torrent (`BEP 17`_).
+		std::vector<std::string> url_seeds;
+
 		// a list of hostname and port pairs, representing DHT nodes to be
 		// added to the session (if DHT is enabled). The hostname may be an IP address.
 		std::vector<std::pair<std::string, int> > dht_nodes;

src/magnet_uri.cpp

@@ -50,7 +50,6 @@ namespace libtorrent
 		ret += to_hex(ih.to_string());
 
 		torrent_status st = handle.status(torrent_handle::query_name);
-
 		if (!st.name.empty())
 		{
 			ret += "&dn=";
@@ -58,13 +57,20 @@ namespace libtorrent
 		}
 
 		std::vector<announce_entry> const& tr = handle.trackers();
-
 		for (std::vector<announce_entry>::const_iterator i = tr.begin(), end(tr.end()); i != end; ++i)
 		{
 			ret += "&tr=";
 			ret += escape_string(i->url.c_str(), i->url.length());
 		}
 
+		std::set<std::string> seeds = handle.url_seeds();
+		for (std::set<std::string>::iterator i = seeds.begin()
+			, end(seeds.end()); i != end; ++i)
+		{
+			ret += "&ws=";
+			ret += escape_string(i->c_str(), i->length());
+		}
+
 		return ret;
 	}
 
@@ -91,6 +97,16 @@ namespace libtorrent
 			ret += escape_string(i->url.c_str(), i->url.length());
 		}
 
+		std::vector<web_seed_entry> const& seeds = info.web_seeds();
+		for (std::vector<web_seed_entry>::const_iterator i = seeds.begin()
+			, end(seeds.end()); i != end; ++i)
+		{
+			if (i->type != web_seed_entry::url_seed) continue;
+
+			ret += "&ws=";
+			ret += escape_string(i->url.c_str(), i->url.length());
+		}
+
 		return ret;
 	}
 
@@ -170,7 +186,22 @@ namespace libtorrent
 			pos += 4;
 			url = uri.substr(pos, uri.find('&', pos) - pos);
 		}
-	
+
+		// parse web seeds out of the magnet link
+		pos = std::string::npos;
+		url = url_has_argument(uri, "ws", &pos);
+		while (pos != std::string::npos)
+		{
+			error_code e;
+			url = unescape_string(url, e);
+			if (e) continue;
+			p.url_seeds.push_back(url);
+			pos = uri.find("&ws=", pos);
+			if (pos == std::string::npos) break;
+			pos += 4;
+			url = uri.substr(pos, uri.find('&', pos) - pos);
+		}
+
 		std::string btih = url_has_argument(uri, "xt");
 		if (btih.empty())
 		{

src/torrent.cpp

@@ -344,6 +344,13 @@ namespace libtorrent
 		if (!m_torrent_file)
 			m_torrent_file = (p.ti ? p.ti : new torrent_info(info_hash));
 
+		// add web seeds from add_torrent_params
+		for (std::vector<std::string>::const_iterator i = p.url_seeds.begin()
+			, end(p.url_seeds.end()); i != end; ++i)
+		{
+			m_web_seeds.push_back(web_seed_entry(*i, web_seed_entry::url_seed));
+		}
+
 		m_trackers = m_torrent_file->trackers();
 		if (m_torrent_file->is_valid())
 		{

test/test_magnet.cpp

@@ -161,6 +161,14 @@ int test_main()
 	TEST_CHECK(ec == error_code(errors::missing_info_hash_in_uri));
 	ec.clear();
 
+	// parse_magnet_uri
+	parse_magnet_uri("magnet:?xt=urn:btih:cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd&ws=http://foo.com/bar&ws=http://bar.com/foo", p, ec);
+	TEST_CHECK(!ec);
+	TEST_EQUAL(p.url_seeds.size(), 2);
+	TEST_EQUAL(p.url_seeds[0], "http://foo.com/bar");
+	TEST_EQUAL(p.url_seeds[1], "http://bar.com/foo");
+	ec.clear();
+
 	parse_magnet_uri("magnet:?xt=blah&dn=foo&dht=127.0.0.1:43", p, ec);
 	TEST_CHECK(ec == error_code(errors::missing_info_hash_in_uri));
 	ec.clear();
@@ -263,6 +271,30 @@ int test_main()
 		printf("%s len: %d\n", magnet.c_str(), int(magnet.size()));
 	}
 
+	// make_magnet_uri
+	{
+		entry info;
+		info["pieces"] = "aaaaaaaaaaaaaaaaaaaa";
+		info["name"] = "test";
+		info["name.utf-8"] = "test";
+		info["piece length"] = 16 * 1024;
+		info["length"] = 3245;
+		entry torrent;
+		torrent["info"] = info;
+
+		torrent["url-list"] = "http://foo.com/bar";
+
+		std::vector<char> buf;
+		bencode(std::back_inserter(buf), torrent);
+		buf.push_back('\0');
+		printf("%s\n", &buf[0]);
+		error_code ec;
+		torrent_info ti(&buf[0], buf.size(), ec);
+
+		std::string magnet = make_magnet_uri(ti);
+		printf("%s len: %d\n", magnet.c_str(), int(magnet.size()));
+		TEST_CHECK(magnet.find("&ws=http%3a%2f%2ffoo.com%2fbar") != std::string::npos);
+	}
 
 	return 0;
 }