[Haskell-cafe] Contributing to http-conduit
Myles C. Maxfield
myles.maxfield at gmail.com
Sat Jan 21 07:38:01 CET 2012
To: Michael Snoyman, author and maintainer of http-conduit
I am interested in contributing to the http-conduit library. I've been
using it for a little while and reading through its source, but have felt
that it could be improved with two features:
- Allowing the caller to know the final URL that ultimately resulted in
the HTTP Source. Because httpRaw is not exported, the caller can't even
re-implement the redirect-following code themselves. Ideally, the caller
would be able to know not only the final URL, but also the entire chain of
URLs that led to the final request. I was thinking that it would be even
cooler if the caller could be notified of these redirects as they happen in
another thread. There are a couple ways to implement this that I have been
- A straightforward way would be to add a [W.Ascii] to the type of
Response, and getResponse can fill in this extra field.
knows about the Request so it can tell if the response should be
- It would be nice for the caller to be able to know in real time
what URLs the request is being redirected to. A possible way to do this
would be for the 'http' function to take an extra argument of type (Maybe
(Control.Concurrent.Chan W.Ascii)) which httpRaw can push URLs
into. If the
caller doesn't want to use this variable, they can simply pass Nothing.
Otherwise, the caller can create an IO thread which reads the Chan until
some termination condition is met (Perhaps this will change the
type of the
extra argument to (Maybe (Chan (Maybe W.Ascii)))). I like this solution,
though I can see how it could be considered too heavyweight.
- Making the redirection aware of cookies. There are redirects around
the web where the first URL returns a Set-Cookie header and a 3xx code
which redirects to another site that expects the cookie that the first HTTP
transaction set. I propose to add an (IORef to a Data.Set of Cookies) to
the Manager datatype, letting the Manager act as a cookie store as well as
a repository of available TCP connections. httpRaw could deal with the
cookie store. Network.HTTP.Types does not declare a Cookie datatype, so I
would probably be adding one. I would probably take it directly from
I'd be happy to do both of these things, but I'm hoping for your input on
how to go about this endeavor. Are these features even good to be pursuing?
Should I be going about this entirely differently?
Myles C. Maxfield
P.S. I'm curious about the lack of Network.URI throughout
Network.HTTP.Conduit. Is there a particular design decision that led you to
use raw ascii strings?
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