;;; http-twiddle.el -- send & twiddle & resend HTTP requests
;;
;; Version 1.0 written by Luke Gorrie <luke@synap.se> in February 2006
;; This program belongs to the public domain.
;;
;; (downloaded from http://fresh.homeunix.net/~luke/misc/emacs/http-twiddle.el)
;;
;; This is a program for testing hand-written HTTP requests. You write
;; your request in an Emacs buffer (using http-twiddle-mode) and then
;; press `C-c C-c' each time you want to try sending it to the server.
;; This way you can interactively debug the requests. To change port or
;; destination do `C-u C-c C-c'.
;;
;; The program is particularly intended for the POST-"500 internal
;; server error"-edit-POST loop of integration with SOAP programs.
;;
;; The mode is activated by `M-x http-twiddle-mode' or automatically
;; when opening a filename ending with .http-twiddle.
;;
;; The request can either be written from scratch or you can paste it
;; from a snoop/tcpdump and then twiddle from there.
;;
;; See the documentation for the `http-twiddle-mode' and
;; `http-twiddle-mode-send' functions below for more details and try
;; `M-x http-twiddle-mode-demo' for a simple get-started example.
;;
;; Tested with GNU Emacs 21.4.1 and not tested/ported on XEmacs yet.

;;; Example buffer:

;; POST / HTTP/1.0
;; Connection: close
;; Content-Length: $Content-Length
;;
;; The request body goes here

(require 'font-lock)                    ; faces

(eval-when-compile
  (unless (fboundp 'define-minor-mode)
    (require 'easy-mmode)
    (defalias 'define-minor-mode 'easy-mmode-define-minor-mode))
  (require 'cl))

(define-minor-mode http-twiddle-mode
  "Major mode for twiddling around with HTTP requests and sending them.
Use `http-twiddle-mode-send' (\\[http-twiddle-mode-send]) to send the request."
  nil
  " http-twiddle"
  '(("\C-c\C-c" . http-twiddle-mode-send)))

(defvar http-twiddle-show-request t
  "*Show the request in the transcript.")

(add-to-list 'auto-mode-alist '("\\.http-twiddle$" . http-twiddle-mode))

(defvar http-twiddle-endpoint nil
  "Cache of the (HOST PORT) to send the request to.")

(defvar http-twiddle-process nil
  "Socket connected to the webserver.")

(defvar http-twiddle-port-history '()
  "History of port arguments entered in the minibuffer.
\(To make XEmacs happy.)")

(defvar http-twiddle-host-history '()
  "History of port arguments entered in the minibuffer.
\(To make XEmacs happy.)")

(defun http-twiddle-mode-send (host port)
  "Send the current buffer to the server.
Linebreaks are automatically converted to CRLF (\\r\\n) format and any
occurences of \"$Content-Length\" are replaced with the actual content
length."
  (interactive (http-twiddle-read-endpoint))
  ;; close any old connection
  (when http-twiddle-process
    (kill-buffer (process-buffer http-twiddle-process)))
  (let ((content (buffer-string)))
    (with-temp-buffer
      (insert content)
      (http-twiddle-convert-cr-to-crlf)
      (http-twiddle-expand-content-length)
      (let ((request (buffer-string)))
        (setq http-twiddle-process
              (open-network-stream "http-twiddle" "*HTTP Twiddle*" host port))
        (set-process-filter http-twiddle-process 'http-twiddle-process-filter)
        (set-process-sentinel http-twiddle-process 'http-twiddle-process-sentinel)
        (process-send-string http-twiddle-process request)
        (save-selected-window
          (pop-to-buffer (process-buffer http-twiddle-process))
          (when http-twiddle-show-request
            (insert request)
            (set-window-start (selected-window) (point))
            (add-text-properties (point-min) (point-max)
                                 '(face font-lock-comment-face)))
          (set-mark (point)))))))

(defun http-twiddle-read-endpoint ()
  "Return the endpoint (HOST PORT) to send the request to."
  (if (and http-twiddle-endpoint (null current-prefix-arg))
      http-twiddle-endpoint
    (setq http-twiddle-endpoint
          (list (read-string "Host: (default localhost) "
                             nil 'http-twiddle-host-history "localhost")
                (let ((input (read-from-minibuffer "Port: " nil nil t 'http-twiddle-port-history)))
                  (if (integerp input)
                      input
                    (error "Not an integer: %S" input)))))))

(defun http-twiddle-convert-cr-to-crlf ()
  "Convert \\n linebreaks to \\r\\n in the whole buffer."
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward "[^\r]\n" nil t)
      (backward-char)
      (insert "\r"))))

(defun http-twiddle-expand-content-length ()
  "Replace any occurences of $Content-Length with the actual Content-Length."
  (save-excursion
    (goto-char (point-min))
    (let ((content-length
           (save-excursion (when (search-forward "\r\n\r\n" nil t)
                             (- (point-max) (point))))))
      (unless (null content-length)
        (let ((case-fold-search t))
          (while (search-forward "$content-length" nil t)
            (replace-match (format "%d" content-length) nil t)))))))

(defun http-twiddle-process-filter (process string)
  "Process data from the socket by inserting it at the end of the buffer."
  (with-current-buffer (process-buffer process)
    (goto-char (point-max))
    (insert string)))

(defun http-twiddle-process-sentinel (process what)
  (with-current-buffer (process-buffer process)
    (goto-char (point-max))
    (let ((start (point)))
      (insert "Connection closed\n")
      (add-text-properties start (point) '(face font-lock-string-face)))))

(defun http-twiddle-mode-demo ()
  (interactive)
  (pop-to-buffer (get-buffer-create "*http-twiddle demo*"))
  (http-twiddle-mode 1)
  (erase-buffer)
  (insert "POST / HTTP/1.0\nContent-Length: $Content-Length\nConnection: close\n\nThis is the POST body.\n")
  (message "Now press `C-c C-c' and enter a webserver address (e.g. google.com port 80)."))

(provide 'http-twiddle)