url-http-ntlm: Override url-http-parse-headers redirect handling

[gnu-emacs-elpa] / packages / url-http-ntlm / url-http-ntlm-parse-headers-24.4.el

;;; url-http-ntlm-parse-headers-24.4.el --- Override url-http-parse-headers

;; Copyright (C) 1999, 2001, 2004-2014 Free Software Foundation, Inc.

;; Author: Bill Perry <wmperry@gnu.org>
;; Keywords: comm, data, processes

;; This file is part of GNU Emacs.
;;
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Override url-http-parse-headers to clear Authorization headers
;; from url-http-extra-headers prior to executing a redirect.  The
;; only change is to apply this backward-compatible patch:
;;
;; diff --git a/lisp/url/url-http.el b/lisp/url/url-http.el
;; index b0a3b68..80d9cca 100644
;; --- a/lisp/url/url-http.el
;; +++ b/lisp/url/url-http.el
;; @@ -617,6 +617,15 @@ should be shown to the user."
;;                 ;; compute the redirection relative to the URL of the proxy.
;;             (setq redirect-uri
;;                   (url-expand-file-name redirect-uri url-http-target-url)))
;; +       ;; Do not automatically include an authorization header in the
;; +       ;; 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)))
;;             (let ((url-request-method url-http-method)
;;               (url-request-data url-http-data)
;;               (url-request-extra-headers url-http-extra-headers))

;;; Code:

(eval-when-compile (require 'cl))

(require 'url-gw)
(require 'url-parse)
(require 'url-cookie)
(require 'mail-parse)
(require 'url-auth)
(require 'url)
(autoload 'url-cache-create-filename "url-cache")
(require 'url-http)

(defvar url-http-process)
(defvar url-http-end-of-headers)
(defvar url-http-response-version)
(defvar url-http-response-status)
(defvar url-http-target-url)
(defvar url-http-method)
(defvar url-http-data)
(defvar url-http-extra-headers)
(defvar url-callback-arguments)
(defvar url-callback-function)

(defun url-http-parse-headers ()
  "Parse and handle HTTP specific headers.
Return t if and only if the current buffer is still active and
should be shown to the user."
  ;; The comments after each status code handled are taken from RFC
  ;; 2616 (HTTP/1.1)
  (url-http-mark-connection-as-free (url-host url-current-object)
                                    (url-port url-current-object)
                                    url-http-process)

  (if (or (not (boundp 'url-http-end-of-headers))
          (not url-http-end-of-headers))
      (error "Trying to parse headers in odd buffer: %s" (buffer-name)))
  (goto-char (point-min))
  (url-http-debug "url-http-parse-headers called in (%s)" (buffer-name))
  (url-http-parse-response)
  (mail-narrow-to-head)
  ;;(narrow-to-region (point-min) url-http-end-of-headers)
  (let ((connection (mail-fetch-field "Connection")))
    ;; In HTTP 1.0, keep the connection only if there is a
    ;; "Connection: keep-alive" header.
    ;; In HTTP 1.1 (and greater), keep the connection unless there is a
    ;; "Connection: close" header
    (cond
     ((string= url-http-response-version "1.0")
      (unless (and connection
                   (string= (downcase connection) "keep-alive"))
        (delete-process url-http-process)))
     (t
      (when (and connection
                 (string= (downcase connection) "close"))
        (delete-process url-http-process)))))
  (let* ((buffer (current-buffer))
         (class (/ url-http-response-status 100))
         (success nil)
         ;; other status symbols: jewelry and luxury cars
         (status-symbol (cadr (assq url-http-response-status url-http-codes))))
    (url-http-debug "Parsed HTTP headers: class=%d status=%d"
                    class url-http-response-status)
    (when (url-use-cookies url-http-target-url)
      (url-http-handle-cookies))

    (pcase class
      ;; Classes of response codes
      ;;
      ;; 5xx = Server Error
      ;; 4xx = Client Error
      ;; 3xx = Redirection
      ;; 2xx = Successful
      ;; 1xx = Informational
      (1                                ; Information messages
       ;; 100 = Continue with request
       ;; 101 = Switching protocols
       ;; 102 = Processing (Added by DAV)
       (url-mark-buffer-as-dead buffer)
       (error "HTTP responses in class 1xx not supported (%d)"
              url-http-response-status))
      (2                                ; Success
       ;; 200 Ok
       ;; 201 Created
       ;; 202 Accepted
       ;; 203 Non-authoritative information
       ;; 204 No content
       ;; 205 Reset content
       ;; 206 Partial content
       ;; 207 Multi-status (Added by DAV)
       (pcase status-symbol
         ((or `no-content `reset-content)
          ;; No new data, just stay at the same document
          (url-mark-buffer-as-dead buffer))
         (_
          ;; Generic success for all others.  Store in the cache, and
          ;; mark it as successful.
          (widen)
          (if (and url-automatic-caching (equal url-http-method "GET"))
              (url-store-in-cache buffer))))
       (setq success t))
      (3                                ; Redirection
       ;; 300 Multiple choices
       ;; 301 Moved permanently
       ;; 302 Found
       ;; 303 See other
       ;; 304 Not modified
       ;; 305 Use proxy
       ;; 307 Temporary redirect
       (let ((redirect-uri (or (mail-fetch-field "Location")
                               (mail-fetch-field "URI"))))
         (pcase status-symbol
           (`multiple-choices       ; 300
            ;; Quoth the spec (section 10.3.1)
            ;; -------------------------------
            ;; The requested resource corresponds to any one of a set of
            ;; representations, each with its own specific location and
            ;; agent-driven negotiation information is being provided so
            ;; that the user can select a preferred representation and
            ;; redirect its request to that location.
            ;; [...]
            ;; If the server has a preferred choice of representation, it
            ;; SHOULD include the specific URI for that representation in
            ;; the Location field; user agents MAY use the Location field
            ;; value for automatic redirection.
            ;; -------------------------------
            ;; We do not support agent-driven negotiation, so we just
            ;; redirect to the preferred URI if one is provided.
            nil)
           ((or `moved-permanently `found `temporary-redirect) ; 301 302 307
            ;; If the 301|302 status code is received in response to a
            ;; request other than GET or HEAD, the user agent MUST NOT
            ;; automatically redirect the request unless it can be
            ;; confirmed by the user, since this might change the
            ;; conditions under which the request was issued.
            (unless (member url-http-method '("HEAD" "GET"))
              (setq redirect-uri nil)))
           (`see-other                  ; 303
            ;; The response to the request can be found under a different
            ;; URI and SHOULD be retrieved using a GET method on that
            ;; resource.
            (setq url-http-method "GET"
                  url-http-data nil))
           (`not-modified               ; 304
            ;; The 304 response MUST NOT contain a message-body.
            (url-http-debug "Extracting document from cache... (%s)"
                            (url-cache-create-filename (url-view-url t)))
            (url-cache-extract (url-cache-create-filename (url-view-url t)))
            (setq redirect-uri nil
                  success t))
           (`use-proxy                  ; 305
            ;; The requested resource MUST be accessed through the
            ;; proxy given by the Location field.  The Location field
            ;; gives the URI of the proxy.  The recipient is expected
            ;; to repeat this single request via the proxy.  305
            ;; responses MUST only be generated by origin servers.
            (error "Redirection thru a proxy server not supported: %s"
                   redirect-uri))
           (_
            ;; Treat everything like '300'
            nil))
         (when redirect-uri
           ;; Clean off any whitespace and/or <...> cruft.
           (if (string-match "\\([^ \t]+\\)[ \t]" redirect-uri)
               (setq redirect-uri (match-string 1 redirect-uri)))
           (if (string-match "^<\\(.*\\)>$" redirect-uri)
               (setq redirect-uri (match-string 1 redirect-uri)))

           ;; Some stupid sites (like sourceforge) send a
           ;; non-fully-qualified URL (ie: /), which royally confuses
           ;; the URL library.
           (if (not (string-match url-nonrelative-link redirect-uri))
               ;; Be careful to use the real target URL, otherwise we may
               ;; compute the redirection relative to the URL of the proxy.
               (setq redirect-uri
                     (url-expand-file-name redirect-uri url-http-target-url)))
           ;; Do not automatically include an authorization header in the
           ;; 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)))
           (let ((url-request-method url-http-method)
                 (url-request-data url-http-data)
                 (url-request-extra-headers url-http-extra-headers))
             ;; Check existing number of redirects
             (if (or (< url-max-redirections 0)
                     (and (> url-max-redirections 0)
                          (let ((events (car url-callback-arguments))
                                (old-redirects 0))
                            (while events
                              (if (eq (car events) :redirect)
                                  (setq old-redirects (1+ old-redirects)))
                              (and (setq events (cdr events))
                                   (setq events (cdr events))))
                            (< old-redirects url-max-redirections))))
                 ;; url-max-redirections hasn't been reached, so go
                 ;; ahead and redirect.
                 (progn
                   ;; Remember that the request was redirected.
                   (setf (car url-callback-arguments)
                         (nconc (list :redirect redirect-uri)
                                (car url-callback-arguments)))
                   ;; Put in the current buffer a forwarding pointer to the new
                   ;; destination buffer.
                   ;; FIXME: This is a hack to fix url-retrieve-synchronously
                   ;; without changing the API.  Instead url-retrieve should
                   ;; either simply not return the "destination" buffer, or it
                   ;; should take an optional `dest-buf' argument.
                   (set (make-local-variable 'url-redirect-buffer)
                        (url-retrieve-internal
                         redirect-uri url-callback-function
                         url-callback-arguments
                         (url-silent url-current-object)
                         (not (url-use-cookies url-current-object))))
                   (url-mark-buffer-as-dead buffer))
               ;; We hit url-max-redirections, so issue an error and
               ;; stop redirecting.
               (url-http-debug "Maximum redirections reached")
               (setf (car url-callback-arguments)
                     (nconc (list :error (list 'error 'http-redirect-limit
                                               redirect-uri))
                            (car url-callback-arguments)))
               (setq success t))))))
      (4                                ; Client error
       ;; 400 Bad Request
       ;; 401 Unauthorized
       ;; 402 Payment required
       ;; 403 Forbidden
       ;; 404 Not found
       ;; 405 Method not allowed
       ;; 406 Not acceptable
       ;; 407 Proxy authentication required
       ;; 408 Request time-out
       ;; 409 Conflict
       ;; 410 Gone
       ;; 411 Length required
       ;; 412 Precondition failed
       ;; 413 Request entity too large
       ;; 414 Request-URI too large
       ;; 415 Unsupported media type
       ;; 416 Requested range not satisfiable
       ;; 417 Expectation failed
       ;; 422 Unprocessable Entity (Added by DAV)
       ;; 423 Locked
       ;; 424 Failed Dependency
       (setq success
             (pcase status-symbol
               (`unauthorized                   ; 401
                ;; The request requires user authentication.  The response
                ;; MUST include a WWW-Authenticate header field containing a
                ;; challenge applicable to the requested resource.  The
                ;; client MAY repeat the request with a suitable
                ;; Authorization header field.
                (url-http-handle-authentication nil))
               (`payment-required              ; 402
                ;; This code is reserved for future use
                (url-mark-buffer-as-dead buffer)
                (error "Somebody wants you to give them money"))
               (`forbidden                      ; 403
                ;; The server understood the request, but is refusing to
                ;; fulfill it.  Authorization will not help and the request
                ;; SHOULD NOT be repeated.
                t)
               (`not-found                      ; 404
                ;; Not found
                t)
               (`method-not-allowed             ; 405
                ;; The method specified in the Request-Line is not allowed
                ;; for the resource identified by the Request-URI.  The
                ;; response MUST include an Allow header containing a list of
                ;; valid methods for the requested resource.
                t)
               (`not-acceptable         ; 406
                ;; The resource identified by the request is only capable of
                ;; generating response entities which have content
                ;; characteristics not acceptable according to the accept
                ;; headers sent in the request.
                t)
               (`proxy-authentication-required ; 407
                ;; This code is similar to 401 (Unauthorized), but indicates
                ;; that the client must first authenticate itself with the
                ;; proxy.  The proxy MUST return a Proxy-Authenticate header
                ;; field containing a challenge applicable to the proxy for
                ;; the requested resource.
                (url-http-handle-authentication t))
               (`request-timeout                ; 408
                ;; The client did not produce a request within the time that
                ;; the server was prepared to wait.  The client MAY repeat
                ;; the request without modifications at any later time.
                t)
               (`conflict                       ; 409
                ;; The request could not be completed due to a conflict with
                ;; the current state of the resource.  This code is only
                ;; allowed in situations where it is expected that the user
                ;; might be able to resolve the conflict and resubmit the
                ;; request.  The response body SHOULD include enough
                ;; information for the user to recognize the source of the
                ;; conflict.
                t)
               (`gone                          ; 410
                ;; The requested resource is no longer available at the
                ;; server and no forwarding address is known.
                t)
               (`length-required                ; 411
                ;; The server refuses to accept the request without a defined
                ;; Content-Length.  The client MAY repeat the request if it
                ;; adds a valid Content-Length header field containing the
                ;; length of the message-body in the request message.
                ;;
                ;; NOTE - this will never happen because
                ;; `url-http-create-request' automatically calculates the
                ;; content-length.
                t)
               (`precondition-failed            ; 412
                ;; The precondition given in one or more of the
                ;; request-header fields evaluated to false when it was
                ;; tested on the server.
                t)
               ((or `request-entity-too-large `request-uri-too-large) ; 413 414
                ;; The server is refusing to process a request because the
                ;; request entity|URI is larger than the server is willing or
                ;; able to process.
                t)
               (`unsupported-media-type ; 415
                ;; The server is refusing to service the request because the
                ;; entity of the request is in a format not supported by the
                ;; requested resource for the requested method.
                t)
               (`requested-range-not-satisfiable ; 416
                ;; A server SHOULD return a response with this status code if
                ;; a request included a Range request-header field, and none
                ;; of the range-specifier values in this field overlap the
                ;; current extent of the selected resource, and the request
                ;; did not include an If-Range request-header field.
                t)
               (`expectation-failed             ; 417
                ;; The expectation given in an Expect request-header field
                ;; could not be met by this server, or, if the server is a
                ;; proxy, the server has unambiguous evidence that the
                ;; request could not be met by the next-hop server.
                t)
               (_
                ;; The request could not be understood by the server due to
                ;; malformed syntax.  The client SHOULD NOT repeat the
                ;; request without modifications.
                t)))
       ;; Tell the callback that an error occurred, and what the
       ;; status code was.
       (when success
         (setf (car url-callback-arguments)
               (nconc (list :error (list 'error 'http url-http-response-status))
                      (car url-callback-arguments)))))
      (5
       ;; 500 Internal server error
       ;; 501 Not implemented
       ;; 502 Bad gateway
       ;; 503 Service unavailable
       ;; 504 Gateway time-out
       ;; 505 HTTP version not supported
       ;; 507 Insufficient storage
       (setq success t)
       (pcase url-http-response-status
         (`not-implemented              ; 501
          ;; The server does not support the functionality required to
          ;; fulfill the request.
          nil)
         (`bad-gateway                  ; 502
          ;; The server, while acting as a gateway or proxy, received
          ;; an invalid response from the upstream server it accessed
          ;; in attempting to fulfill the request.
          nil)
         (`service-unavailable          ; 503
          ;; The server is currently unable to handle the request due
          ;; to a temporary overloading or maintenance of the server.
          ;; The implication is that this is a temporary condition
          ;; which will be alleviated after some delay.  If known, the
          ;; length of the delay MAY be indicated in a Retry-After
          ;; header.  If no Retry-After is given, the client SHOULD
          ;; handle the response as it would for a 500 response.
          nil)
         (`gateway-timeout              ; 504
          ;; The server, while acting as a gateway or proxy, did not
          ;; receive a timely response from the upstream server
          ;; specified by the URI (e.g. HTTP, FTP, LDAP) or some other
          ;; auxiliary server (e.g. DNS) it needed to access in
          ;; attempting to complete the request.
          nil)
         (`http-version-not-supported   ; 505
          ;; The server does not support, or refuses to support, the
          ;; HTTP protocol version that was used in the request
          ;; message.
          nil)
         (`insufficient-storage         ; 507 (DAV)
          ;; The method could not be performed on the resource
          ;; because the server is unable to store the representation
          ;; needed to successfully complete the request.  This
          ;; condition is considered to be temporary.  If the request
          ;; which received this status code was the result of a user
          ;; action, the request MUST NOT be repeated until it is
          ;; requested by a separate user action.
          nil))
       ;; Tell the callback that an error occurred, and what the
       ;; status code was.
       (when success
         (setf (car url-callback-arguments)
               (nconc (list :error (list 'error 'http url-http-response-status))
                      (car url-callback-arguments)))))
      (_
       (error "Unknown class of HTTP response code: %d (%d)"
              class url-http-response-status)))
    (if (not success)
        (url-mark-buffer-as-dead buffer)
      (url-handle-content-transfer-encoding))
    (url-http-debug "Finished parsing HTTP headers: %S" success)
    (widen)
    (goto-char (point-min))
    success))

(provide 'url-http-ntlm-parse-headers-24.4)

;;; url-http-ntlm-parse-headers-24.4.el ends here