This morning, I was able to enable seeking when streaming a contact’s library in my Telepathy extension for Banshee. For the longest time, I figured it would just work. Of course, it’s not that easy. So, last night I decided to do some googling. In turns out that, when streaming via HTTP, to request a skip, an HTTP Range header gets sent within the body of the request. So, the full HTTP request to skip to some point in a stream may look something like the following, which I captured from totem (the key bit is in bold):
GET / HTTP/1.1 Host: localhost:8080 Connection: close icy-metadata: 1 transferMode.dlna.org: Streaming Range: bytes=2602384- User-Agent: GStreamer souphttpsrc libsoup/2.26.0
To identify to the client making the request that seeking is supported, a 206 Partial Content status code must be sent back, instead of the usual 200 OK. In addition to this, a Content-Range header field must be included indicating where the partial content starts and ends. Therefore, the Content-length header must also be augmented to account for the size of the partial content being sent.
So, to enable seeking in my stream server within my Banshee extension, all I had to do was send the appropriate HTTP status code, headers, and partial stream of music.
Skip, skip, skip to my loo.