Modified metadata interface to be tag independent, added JSON api.

client/metadata.h

@@ -55,7 +55,7 @@ public:
 
 	std::string serialize()
 	{
-		return METADATA + ":" + _msg->dump() + "\n";
+		return METADATA + ":" + _msg->dump();
 	}
 
 	void tag(std::string name, std::string value)

server/streamServer.cpp

@@ -385,10 +385,14 @@ void StreamServer::ProcessRequest(const jsonrpcpp::request_ptr request, jsonrpcp
 		{
 			if (request->method.find("Stream.SetMeta") == 0)
 			{
-				/// Request:      {"id":4,"jsonrpc":"2.0","method":"Stream.SetMeta","params":{"id":"Spotify","meta": {"album": "some album", "artist": "some artist", "track": "some track"...}}}
-				/// Response:     {"id":4,"jsonrpc":"2.0","result":{"stream_id":"stream 1"}}
+				/// Request:      {"id":4,"jsonrpc":"2.0","method":"Stream.SetMeta","params":{"stream_id":"Spotify",
+ 				///                "meta": {"album": "some album", "artist": "some artist", "track": "some track"...}}}
+				///
+				/// Response:     {"id":4,"jsonrpc":"2.0","result":{"stream_id":"Spotify"}}
 				/// Call onMetaChanged(const PcmStream* pcmStream) for updates and notifications
 
+				LOG(INFO) << "Stream.SetMeta(" << request->params.get("stream_id") << ")" << request->params.get("meta") <<"\n";
+
 				// Find stream
 				string streamId = request->params.get("stream_id");
 				PcmStreamPtr stream = streamManager_->getStream(streamId);
@@ -396,14 +400,10 @@ void StreamServer::ProcessRequest(const jsonrpcpp::request_ptr request, jsonrpcp
 					throw jsonrpcpp::InternalErrorException("Stream not found", request->id);
 
 				// Set metadata from request
-				// stream-> 
+				stream->setMeta(request->params.get("meta"));
 
-				// Update clients 
 				// Setup response
-
-				// Trigger notifications
-				// onMetaChanged(stream);
-				// notification.reset(new jsonrpcpp::Notification("Client.OnLatencyChanged", jsonrpcpp::Parameter("id", clientInfo->id, "latency", clientInfo->config.latency)));
+				result["stream_id"] = streamId;
 			}
 			else
 				throw jsonrpcpp::MethodNotFoundException(request->id);

server/streamreader/README.meta

@@ -0,0 +1,31 @@
+Metadata tags
+=============
+The metatag interface will propegate anything to the client, ie no restrictions on the tags.
+But, to avoid total confusion in the tag display app (like Kodi), we need some groundrules.
+
+My suggestion is to stick with the Vorbis standard as described in:
+
+	http://www.xiph.org/vorbis/doc/v-comment.html
+	https://wiki.xiph.org/Field_names
+
+In addition we should accept unique identifiers of the stream such as Spotify track ID or 
+MusicBrainz id which can be used to lookup additional information online.
+
+Example:
+	ARTIST: Pink Floyd
+	ALBUM: Dark Side of the Moon
+	TITLE: Money
+	METADATA_BLOCK_PICTURE: base64 (https://xiph.org/flac/format.html#metadata_block_picture) 
+
+
+Parsing tags from streams
+=========================
+I've implemented parsing tags from Librespot, but, as Librespot doesn't export anything more than
+track title I added a patch 'librespot-meta.patch' to apply to get artist/title.
+
+TBH, the meta tag output from players are a mess, neither Librespot nor Shairport-sync associate
+metadata with their audio interfaces, ie they don't even export metadata when the audio interface
+supports it, at least Shairport-sync exports a ritch set of data. 
+
+So, to get artist/album apply the patch to librespot and recompile, otherwise you will only get the 
+track title.

server/streamreader/librespot-meta.patch

@@ -0,0 +1,31 @@
+*** librespot/src/player.rs	2017-11-30 08:16:40.865939287 +0100
+--- librespot.meta/src/player.rs	2017-11-30 08:14:39.232954039 +0100
+***************
+*** 13,19 ****
+  use audio_backend::Sink;
+  use audio::{AudioFile, AudioDecrypt};
+  use audio::{VorbisDecoder, VorbisPacket};
+! use metadata::{FileFormat, Track, Metadata};
+  use mixer::AudioFilter;
+  
+  #[derive(Clone)]
+--- 13,19 ----
+  use audio_backend::Sink;
+  use audio::{AudioFile, AudioDecrypt};
+  use audio::{VorbisDecoder, VorbisPacket};
+! use metadata::{Artist, FileFormat, Track, Metadata};
+  use mixer::AudioFilter;
+  
+  #[derive(Clone)]
+***************
+*** 384,389 ****
+--- 384,392 ----
+  
+          info!("Track \"{}\" loaded", track.name);
+  
++ 	let artist = Artist::get(&self.session, track.artists[0]).wait().unwrap();
++         info!("metadata:{{\"ARTIST\":\"{}\",\"TITLE\":\"{}\"}}", artist.name, track.name);
++ 
+          Some(decoder)
+      }
+  }

server/streamreader/pcmStream.cpp

@@ -179,3 +179,17 @@ json PcmStream::toJson() const
 	return j;
 }
 
+std::shared_ptr<msg::StreamTags> PcmStream::getMeta() const
+{
+	return meta_;
+}
+
+void PcmStream::setMeta(json jtag)
+{
+	meta_.reset(new msg::StreamTags(jtag));
+
+	// Trigger a stream update
+	if (pcmListener_)
+		pcmListener_->onMetaChanged(this);
+}
+

server/streamreader/pcmStream.h

@@ -83,15 +83,12 @@ public:
 	virtual const std::string& getId() const;
 	virtual const SampleFormat& getSampleFormat() const;
 
+	std::shared_ptr<msg::StreamTags> getMeta() const;
+	void setMeta(json j);
+
 	virtual ReaderState getState() const;
 	virtual json toJson() const;
 
-	//const msg::StreamTags *getMeta()
-        std::shared_ptr<msg::StreamTags> getMeta() const
-	{
-		return meta_;
-	}
-
 
 protected:
 	std::condition_variable cv_;
@@ -99,6 +96,7 @@ protected:
 	std::thread thread_;
 	std::atomic<bool> active_;
 
+
 	virtual void worker() = 0;
 	virtual bool sleep(int32_t ms);
 	void setState(const ReaderState& newState);
@@ -112,8 +110,6 @@ protected:
 	std::unique_ptr<Encoder> encoder_;
 	std::string name_;
 	ReaderState state_;
-
-	// Stream metadata
         std::shared_ptr<msg::StreamTags> meta_;
 };
 

server/streamreader/spotifyStream.cpp

@@ -93,6 +93,9 @@ void SpotifyStream::initExeAndPath(const std::string& filename)
 
 void SpotifyStream::onStderrMsg(const char* buffer, size_t n)
 {
+	static bool libreelec_patched = false;
+	smatch m;
+
 	// Watch stderr for 'Loading track' messages and set the stream metadata
 	// For more than track name check: https://github.com/plietar/librespot/issues/154
 
@@ -124,29 +127,37 @@ void SpotifyStream::onStderrMsg(const char* buffer, size_t n)
 		LOG(INFO) << "(" << getName() << ") " << logmsg << "\n";
 	}
 
-	// Track tags "Julia Michaels" "Issues - Acoustic"
-	if (logmsg.find("Track tags") != string::npos)
-	{
-		// Traditional Libreelec meta interface, only track name
-		regex re("Track tags \"(.*)\" \"(.*)\"");
-		smatch m;
+	// Librespot patch:
+	// 	info!("metadata:{{\"ARTIST\":\"{}\",\"TITLE\":\"{}\"}}", artist.name, track.name);
+	// non patched:
+	// 	info!("Track \"{}\" loaded", track.name);
 
-		if (regex_search(logmsg, m, re))
+	// If we detect a patched libreelec we don't want to bother with this anymoer
+	// to avoid duplicate metadata pushes
+	if (!libreelec_patched)
+	{
+		static regex re_nonpatched("Track \"(.*)\" loaded");
+ 		if(regex_search(logmsg, m, re_nonpatched))
 		{
-			// Create a new meta struct?
-			LOG(INFO) << "Loading track <" << m[1] << "> <" << m[2] << ">\n";
+			LOG(INFO) << "metadata: <" << m[1] << ">\n";
 
 			json jtag = {
-				{"artist", (string)m[1]},
-                		{"track", (string)m[2]}
+               			{"TITLE", (string)m[1]}
 			};
-			meta_.reset(new msg::StreamTags(jtag));
-
-			// Trigger a stream update
-			if (pcmListener_)
-				pcmListener_->onMetaChanged(this);
+			setMeta(jtag);
 		}
 	}
+
+	// Parse the patched version
+	static regex re_patched("metadata:(.*)");
+	if (regex_search(logmsg, m, re_patched)) 
+	{
+		LOG(INFO) << "metadata: <" << m[1] << ">\n";
+
+		json jtag;
+		setMeta(jtag.parse(m[1]));
+		libreelec_patched = true;
+	}
 }