On Mon, May 16, 2011 at 11:23 AM, Erik de Castro Lopo
Hi all,
I'm continuing work on the HTTP proxy I'm writing. The absolute bare basics are working with Warp, Wai and http-enumerator as long as the upstream web server doesn't send gzipped or chunked data. For these later two cases, httpe-enumerator helpfully gunzips/unchunks the data. That however causes a problem.
If my proxy simply passes the HTTP headers and data it gets from http-enumerator and passes then on to the client, the client barfs because the headers claim the data is gzipped or chunked and the data actually isn't chunked/gzipped.
There are a number of possible solutions to this:
a) Strip the content/transfer-encoding header and add a content-length header instead. I think this is probably possible with the API as it is, but I haven't figured out how yet.
b) Rechunk or re-gzip the data. This seems rather wasteful of CPU resources.
c) Modify the Network.Http.Enumerator.http function so that de-chunking/gunzipping is optional.
d) Expose the iterHeaders function that is internal to the http-enumerator package so that client code can grab the headers before deciding how to handle the body.
Are there any other options I haven't thought of yet?
From the options I have, I actually think d) makes the most sense, Would a patch exposing iterHeaders be accepted?
Cheers, Erik
Short answer is that I'm fine exposing iterHeaders, as long as we put a big fat "advanced users only" comment on it. I agree with you that (b) seems like a bad idea. (a) is definitely possible, if a bit tricky, but it defeats the whole purpose of chunking and gzipping, so it probably shouldn't be considered. I would guess that (c) is really the best option, though I'm guessing you shied away from it because it involved more substantial changes to http-enumerator. Maybe we should consider adding an extra httpAdvanced function that takes additional settings, such as whether or not to automatically de-chunk/de-gzip. I wouldn't be surprised if we come up with more such cases in the future. Michael