Add Support to Stream Videos from Dart as HttpServer

[DartBot]

This issue was originally filed by @pjako

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Currently if I use dart as http server the streaming of a video to HTMLVideoElement doesn't work right, you cant seek and you can loop videos.
https://developer.mozilla.org/en/DOM/HTMLVideoElement

To get that working, dart HttpServer should support streaming http responses.

Not shure if it helps but the problem seems similar...
http://stackoverflow.com/questions/4538810/html5-video-element-non-seekable-when-using-django-development-server

[dgrove]

Set owner to @whesse.
Removed Type-Defect label.
Added Type-Enhancement, Area-IO, Triaged labels.

[whesse]

I believe that to get seeking working on a streamed video, you need to send the "Accept-Ranges" HTTP header in the response, and handle the "Range" header in the requests. I am not sure whether this is more compatible with the Transfer-Encoding: chunked header (streaming), or the Content-Length: header.

If you are doing all of this already, please attach an example of your server code that is not supporting seeking or streaming.

[sgjesse]

When dealing with streaming video the client typically want to use byte ranges. To indicate renges support to the client set the Accept-Ranges header on the response to serve the video:

  response.headers.set(HttpHeaders.ACCEPT_RANGES, "bytes");

Subsequest requests (e.g. seeking) from the client will then contain Range headers, which needs to be parsed. Look for

  request.headers.value("range");

The File class recently had optional start and end arguments added to openRead to help support streaming parts of a file.

We are preparing an article with details on this.

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Added AsDesigned label.

[kevmoo]

Removed Area-IO label.
Added Area-Library, Library-IO labels.