Re: url-http.el: redirection to partial URL with a proxy

[Stefan Monnier]

>> The redirection of a URL retrieval request to a partial (not fully
>> qualified) URL does not work if the retrieval is attempted with a
>> proxy connection. The function url-http-parse-headers in url-http.el
>> constructs a fully qualified URL by using the variable
>> url-current-object. But this variable contains the proxy URL if a proxy
>> is used. This leads to a wrong redirection URL.
>> 
>> The following patch solves this problem. It works because
>> url-http-cookies-sources contains always the original URL as set in the
>> function url-http. Maybe the variable could be renamed because it is
>> useful not just for cookie handling.

> And there's an unneeded `s' at the end, I think I made a typo here :)
> Something like `url-http-target-url' may be better.

I'm thinking of installing the change below, but I have two questions:
- the save-excusion;save-restriction;set-buffer thingy looks very fishy.
  My replacingit with with-current-buffer;save-restriction makes it
  look saner, but maybe there was a reason for the fishiness.
- the url-expand-file-name call looks fishy as well because there's
  no reason to assume that url-http-target-url is a directory, so maybe we
  should use
               (setq redirect-uri
                     (url-expand-file-name redirect-uri
                                           (file-name-directory
                                            url-http-target-url)))

I have no understanding of what the code does, so it's all
shallow-debugging.  Can someone confirm what I'm doing looks reasonable?


        Stefan


--- url-http.el 20 oct 2005 15:44:21 -0400      1.22
+++ url-http.el 17 nov 2005 22:43:05 -0500      
@@ -26,10 +26,9 @@
 
 ;;; Code:
 
-(eval-when-compile
-  (require 'cl)
-  (defvar url-http-extra-headers)
-  (defvar url-http-cookies-sources))
+(eval-when-compile (require 'cl))
+(defvar url-http-extra-headers)
+(defvar url-http-target-url)
 (require 'url-gw)
 (require 'url-util)
 (require 'url-parse)
@@ -358,7 +357,7 @@
 work correctly."
   (let ((cookies (mail-fetch-field "Set-Cookie" nil nil t))
        (cookies2 (mail-fetch-field "Set-Cookie2" nil nil t))
-       (url-current-object url-http-cookies-sources))
+       (url-current-object url-http-target-url))
     (and cookies (url-http-debug "Found %d Set-Cookie headers" (length 
cookies)))
     (and cookies2 (url-http-debug "Found %d Set-Cookie2 headers" (length 
cookies2)))
     (while cookies
@@ -510,7 +509,9 @@
           ;; non-fully-qualified URL (ie: /), which royally confuses
           ;; the URL library.
           (if (not (string-match url-nonrelative-link redirect-uri))
-              (setq redirect-uri (url-expand-file-name redirect-uri)))
+              (setq redirect-uri
+                    (url-expand-file-name redirect-uri
+                                          url-http-target-url)))
           (let ((url-request-method url-http-method)
                 (url-request-data url-http-data)
                 (url-request-extra-headers url-http-extra-headers))
@@ -727,8 +728,7 @@
   (url-http-debug "url-http-end-of-document-sentinel in buffer (%s)"
                  (process-buffer proc))
   (url-http-idle-sentinel proc why)
-  (save-excursion
-    (set-buffer (process-buffer proc))
+  (with-current-buffer (process-buffer proc)
     (goto-char (point-min))
     (if (not (looking-at "HTTP/"))
        ;; HTTP/0.9 just gets passed back no matter what
@@ -1039,8 +1039,7 @@
          (setq buffer nil)
          (error "Could not create connection to %s:%d" (url-host url)
                 (url-port url)))
-      (save-excursion
-       (set-buffer buffer)
+      (with-current-buffer buffer
        (mm-disable-multibyte)
        (setq url-current-object url
              mode-line-format "%b [%s]")
@@ -1060,7 +1059,7 @@
                       url-http-method
                       url-http-extra-headers
                       url-http-data
-                      url-http-cookies-sources))
+                      url-http-target-url))
          (set (make-local-variable var) nil))
 
        (setq url-http-method (or url-request-method "GET")
@@ -1073,7 +1072,7 @@
              url-callback-function callback
              url-callback-arguments cbargs
              url-http-after-change-function 
'url-http-wait-for-headers-change-function
-             url-http-cookies-sources (if (boundp 'proxy-object)
+             url-http-target-url (if (boundp 'proxy-object)
                                           proxy-object
                                         url-current-object))
 
@@ -1096,8 +1095,7 @@
   (declare (special url-http-after-change-function))
   (and (process-buffer proc)
        (/= (length data) 0)
-       (save-excursion
-        (set-buffer (process-buffer proc))
+       (with-current-buffer (process-buffer proc)
         (url-http-debug "Calling after change function `%s' for `%S'" 
url-http-after-change-function proc)
         (funcall url-http-after-change-function
                  (point-max)
@@ -1114,8 +1112,7 @@
     (defun url-http-symbol-value-in-buffer (symbol buffer
                                                   &optional unbound-value)
       "Return the value of SYMBOL in BUFFER, or UNBOUND-VALUE if it is 
unbound."
-      (save-excursion
-       (set-buffer buffer)
+      (with-current-buffer buffer
        (if (not (boundp symbol))
            unbound-value
          (symbol-value symbol))))
@@ -1198,10 +1195,9 @@
     (when (and buffer (= 2 (/ (url-http-symbol-value-in-buffer
                               'url-http-response-status buffer 0) 100)))
       ;; Only parse the options if we got a 2xx response code!
-      (save-excursion
+      (with-current-buffer buffer
        (save-restriction
          (save-match-data
-           (set-buffer buffer)
            (mail-narrow-to-head)
 
            ;; Figure out what methods are supported.