Unhandled error in deflate compression handling

[pocketjoso]

Okay, I have to admit that I have no idea what's going on here, sorry for the vague issue.

Node v0.12.7

var fetch = require('node-fetch')
fetch('http://time-attendance.co.uk')

gives

events.js:85
      throw er; // Unhandled 'error' event
            ^
Error: incorrect header check
    at Zlib._handle.onerror (zlib.js:366:17)

...
The fetch results in a ok response... The promise is not rejected. But I still get this error thrown, somewhere.. Confused. :/

[pocketjoso]

Ah. Just curled that url. A redirect? Not supported in this library?

[pocketjoso]

How do I handle this error? And is it possible to follow the redirect using fetch-node?

[bitinn]

Yep, node-fetch follows redirect by default, so the problem is not the redirect itself, but somehow node.js zlib is not able to handle the deflate response this server is returning.

https://github.com/bitinn/node-fetch/blob/master/index.js#L141

As we do test for deflate response support, my guess would be that particular server is returning something weird.

https://github.com/bitinn/node-fetch/blob/master/test/server.js#L67-L74
https://github.com/bitinn/node-fetch/blob/master/test/test.js#L329-L338

As a workaround for now, setting options compress: false will cause the server to return decompressed content, allowing your fetch to go through.

Neverthless, I think in this case we need to handle this error so that fetch reject the result (to truly fix the problem require checking what went wrong during zlib inflate, maybe open a ticket on node.js core?)

[pocketjoso]

Thanks for your reply.

I think in this case we need to handle this error so that fetch reject the result

Yeah I think so too. As it is now I seem to have no way to handle the error, and I would prefer receive an Error rather than changing the compression mode (I'm making many requests).

to truly fix the problem require checking what went wrong during zlib inflate, maybe open a ticket on node.js core?

Not very read up on these things. How would I be able to tell what wen't wrong during the inflate? Would I not need to get onto the server serving that url? Nvm, I see that the inflate happens on the receiving end. Will do some more research. Will also try doing the same fetch in a browser to see what happens there.

[bitinn]

@pocketjoso I plan to work on this module next week, will update when the fix has landed.

[pocketjoso]

Awesome. :)

[bitinn]

Fixed in v1.3.3, just note that we can't reject the fetch request (because the error is on body, which is a stream) but we do reject it when you call res.text() or res.json().

Otherwise you can use res.body.on('error', handler) to catch it independently.

[pocketjoso]

Excellent, thanks for fixing!