Support Rack::Sendfile middleware

[lfidnl]

Hello.

I've added support of Rack::Sendfile middleware. Before this fixRack::Sendfile does not apply strategy of adding X-Accel-Redirect (or X-Sendfile) header, because Grape returns simple Rack::Response which doesn't respond to to_path method. So I've implemented simple SendfileReponse class which responds to to_path.

[dblock]

Interesting. Lets start with these:

• The test should use Rack::Sendfile, otherwise it's just expecting some contract to be fulfilled.
• Fix build, add to CHANGELOG.

[lfidnl]

Hi! Sorry, for long response.

I wrote test spec/grape/middleware/formatter_spec.rb:286 because condition with Grape::Util::FileResponse wasn't covered. Additionaly, as I understood, I should write some integration test with using Rake::Sendfile middleware, right?

[dblock]

Yes, please and thank you @lfidnl. I am glad this gets cleaned up and tested.

[lfidnl]

@dblock, I've added test, update CHANGELOG and fix build. I hope, I done everything well :)

[dblock]

But this is not true, no? The code change makes it that I don't have to worry about file streamers or any other thing, I can just plop Rack::Sendfile in there and it will "just work", right? Maybe just say that this is compatible with Rack::Sendfile and add a note on what that does?

[lfidnl]

@dblock , thanks for comment! I mean that agrument of file dsl method should respond to to_path method (of couse use Rack::Sendfile shoule be applied in API class).
So it can be FileSteamer with realized to_path method or other object with to_path method. I uses "file streamer" notion for supporting article in the same style.
I think that adding information about Rack::Sendfile will be overkill. I can replace information with this:

For using Rack::Sendfile middleware, specify to_path method in your file streamer class which returns path of served file:

class FileStreamer
  # ...

  def to_path
    @file_path
  end

  # ...
end

Note: don't forget turn on Rack::Sendfile middleware in your API:

class API < Grape::API
  use Rack::Sendfile
end

If you want to just add Rack::Sendfile and I starts to work see my comment on below :)

[dblock]

Ok I get it. I think it should look like the text above, which is If you want a file-like object to be streamed using Rack::Chunked, use stream.

Maybe

If you want to take advantage of Rack::Sendfile, which intercepts responses whose body is being served from a file and replaces it with a server specific X-Sendfile header, ...

Update it as you see fit and I'll merge.

[lfidnl]

Ok. I'll update readme during for couple days

[dblock]

Tests are good. See my above note on README, squash commits please.

[lfidnl]

I think we must rewrite Grape's api for serving file like in Rails framework:

get '/file' do
  file '/path/to/file'
end

file method will create "file streamer" object and if Rack::Sendfile middleware turns on, it will works throurg middleware, otherwise it will stream file through Grape.
It will simplify using of Grape.

Lets create new issue or I'll try to provide propose with Pull Request after closing this PL :)

[dblock]

👍 on extending file to take a path

[lfidnl]

README updated

[dblock]

Merged, thanks.