使用Google App Engine中的Java Servlet进行音频流传输

Question

I am trying to create a URL in my GAE Java web application that can allow streaming an audio file, but so far it only works for direct download. This is what my servlet looks like so far for downloading a file from the BlobStore with BlobKey sent in the "file_id" parameter:

public void doGet(HttpServletRequest req, HttpServletResponse res) 
        throws IOException {

    BlobInfoFactory bif = new BlobInfoFactory();

    BlobKey blobKey = new BlobKey(req.getParameter("file_id"));
    String fileName = bif.loadBlobInfo(blobKey).getFilename();

    res.setContentType("text/plain");
    res.setHeader("Content-Disposition", "attachment; filename=" + fileName);

    blobstoreService.serve(blobKey, res);
}

The servlet is mapped to a URL that looks like this: xxx.appspot.com/fileDownload?file_id=yyy

How could I access this URL on the client side (browser or mobile application) for streaming the audio data instead of doing a direct download? Would I have to change the server side, the client side protocol to access it (instead of HTTP), or both?

Thank you!

Answer 1

1. Check which audio formats are supported by certain browsers . Your best bet would be mp3 audio.

2. Use this html snippet on client side:

   <audio controls> <source src="http://path/to/your/audio/file.mp3" type="audio/mpeg"> Your browser does not support the audio element. </audio>

3. Make sure your server serves audio files as audio/mpeg content type (also the content of your blob must be mp3 file):

   res.setContentType("audio/mpeg");

4. Remove the Content-Disposition header. This is used when you want browser to save a file to local disk.