Implement RFC 7233

[magne4000]

It would be great to support RFC 7233 : Hypertext Transfer Protocol (HTTP/1.1): Range Requests for next major version, at least for non multipart/byteranges media type.

I'm willing to implement this, so please share your thoughts about this.

What must be done:

• Modify send_file method to support Range Requests
  • Use existing conditionnal parameter to enable Range Requests support ?

[davidism]

I'm willing to implement this

Go for it.

[magne4000]

This will actually need some modifications on werkzeug side also, like a more complete approach of https://github.com/pallets/werkzeug/pull/868/files

[magne4000]

Also pallets/werkzeug#978

[magne4000]

The doc of send_file method is already quite heavy, I was thinking of adding something like this:

If `add_etags=True`, `conditional=True` and `filename` is provided, this
method will try to upgrade the response stream to support range requests.
This will allow the request to be answered with partial content response.

Does some of you have a better idea ?

[untitaker]

I don't think it makes sense anymore to invoke make_conditional only when add_etags is set (i.e. dedent the if conditional block)

[magne4000]

See PR #2031