bug#21350: 25.0.50; Do not automatically include authorization header in HTTP redirects

[Thomas Fitzsimmons]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> This patch is required for url-http-ntlm.el to handle redirects.  I'd
>> like someone more familiar with url-http.el to review it.
>
> I'm not sure if there is such a someone, to tell you the truth.  I can
> give you comments about Elisp style:

OK, thanks.

> +        ;; Don't automatically include authorization header in redirect.
> +        ;; If needed it will be regenerated by the relevant auth scheme
> +        ;; when the new request happens.
> +        (setq url-http-extra-headers
> +              (let (result)
> +                (dolist (header url-http-extra-headers)
> +                  (if (not (equal (car header) "Authorization"))
> +                      (push header result)))
> +                (nreverse result)))
>
> IIUC this is like:
>
>   (let ((a (assoc "Authorization" url-http-extra-headers)))
>     (if a (setq url-http-extra-headers (delq a url-http-extra-headers))))
>
> Tho maybe it should be `remq' rather than `delq'.

I was trying to remove all occurrences of "Authorization", just in case,
since that's what url-http-ntlm did.  I looked at remq and delq.  delq
looks like it would be faster.  I'm not sure why I would use remq since
I'm overwriting url-http-extra-headers anyway.

url-http-ntlm did this:

(defun url-http-ntlm-rmssoc (key alist)
  (remove* key alist :key 'car :test 'equal))

but should I avoid using cl-lib in this context?  Another consideration
is that I want to be able to backport this change (as an ELPA-installed
patch) all the way back to Emacs 24.1, so maybe that's another reason
not to use cl-lib.

Thomas