Transfer encoding in HTTP headers

[danielstocks]

Hello,

It seems that window.fetch in the browser will treat Content-Length and Transfer-Encoding differently compared to node-fetch. This causes some headache as a receiving server will have to treat these results differently (stream vs no stream).

This is how I'm calling fetch (both on the client and the server)

fetch("http://localhost:5000/users", { method: "POST" });

Using node-fetch in Node 4.1 yields the following headers on the receiving server:

Transfer-Encoding: chunked
Content-Length:

Where as using window.fetch in Chrome 45.0.2454.85 produces the following:

Content-Length: 0

I'm not sure about this, but my guess is that Transfer-Encoding: chunkedshould only be applied in the cases where you're providing a stream as body. As in this instance: https://github.com/bitinn/node-fetch/blob/master/test/test.js#L436

Otherwise, it should set the content-length header. I.e something like this:

options.headers['Content-Length'] = Buffer.byteLength(body);

I may have misunderstood the spec, so let me know if this fits within the scope of this project or not. If so, I'm happy to submit a PR.

Regards,
Daniel

[bitinn]

I want to make sure I understand your problem:

• Are you saying node-fetch send out request with Transfer-Encoding: chunked by default? Since this is likely a default set by http.request (node.js http module), I wonder their reason behind it.
• Is this a problem for your project? Do you see anything in the Fetch Spec / RFC regarding this?
• Can you reproduce it on service like http://httpbin.org/headers, which should show you the request headers?

[danielstocks]

Are you saying node-fetch send out request with Transfer-Encoding: chunked by default? Since this is likely a default set by http.request (node.js http module), I wonder their reason behind it.

Yes. It's a default set by the node http.request library. If you set a content-length header however, the node http.request will automatically remove the Transfer-Encoding: chunked header, so it's designed to send either of those.

I don't know the reasoning behind it, but I know that many server protocols like WSGI (for running python apps) don't support Transfer-Encoding: chunked (pallets/flask#367).

It makes sense that if you're not sending a stream, then you should be setting the `content-length' header, which node-fetch currently does not. It'll explicitly tell a server that it's not dealing with a stream. To be consistent with the current implementation of window.fetch in chrome, this would be the right thing do (although I don't know if they've implemented fetch correctly but I'd assume so)

It's only reproducible via POST/PUT/PATCH requests so I cannot show it to you on http://httpbin.org/headers because it only allows GET (postmanlabs/httpbin#248)

[bitinn]

Fixed in v1.3.3