I'm running into a problem with duplicated cookies. This is due to
misbehaving servers sending back duplicate Set-Cookie headers in the
same response, like this:
Set-Cookie: JSESSIONID=foo; Path=/; Secure
Set-Cookie: JSESSIONID=bar; Path=/; Secure
Firefox deals with this by picked the last cookie value specified.
There is no logic in drakma currently to handle that, and so my
cookie-jar is getting two JSESSION cookies, and further requests are
sending both cookies. I do not control the servers returning me these
duplicate headers.
This patch adds a unique-cookies function that iterates through cookie
objects, keeping only the last one. This is then called in get-cookies
to ensure no duplicate cookie objects are propagated to the rest of the
system. I've got my "make it work on a friday afternoon" solution in
the attached patch, but I'm not really happy with it long term, and
wanted some advice. Problems I see:
* I think the dolist/find combination is a recipe for performance
problems with many cookies
* It seems odd to build up a list of cookies, then rebuild it
* The most common case of no duplicate cookies has an extra bunch of
consing to rebuilding up the list
* I think there should be a user choice of "ignore all but the last
cookie" vs "ignore all but the first cookie" vs "leave them all in
there"
Some thoughts on how to proceed:
1. Add a exported *redundant-cookie-strategy* variable, with values
:keep-all, :keep-first, and :keep-last, defaulting to :keep-all
(the current behavior).
2. remove the unique-cookies function and rewrite get-cookies to
implement the *redundant-cookie-strategy*, making one pass through
parsed-cookies.
3. leave get-cookies mostly as-is, but add some detection for
duplicates, and run unique-cookies only if it we need to
Thanks,
Ryan
PS: I'm still kinda new to contributing on open source projects via
emailed patches, sorry if this is in a bad format. I read
http://weitz.de/patches.html and created this patch from my working copy
using >diff -u ../drakma-1.1.0/cookies.lisp cookies.lisp
