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;;; simple-server.el --- a SIMPLE web-server run by emacs
;; Copyright (C) 2008 Eric Schulte
;; Author: Eric Schulte
;; This file is not currently part of GNU Emacs.
;; This program 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 2, or (at
;; your option) any later version.
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program ; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Attribution (read: unwitting authors) :
;; This borrows heavily from the following
;; EmacsEchoServer on the Emacs Wiki at
;; httpd.el by Eric Marsden and John Wiegley
;; hunchentoot a common lisp web-server
;;; Commentary:
;; `simple-server' implements a very simple http server which will
;; hopefully be able to hand off GET requests to functions specified
;; in the `ss-dispatch-table'.
;; The `ss-dispatch-table' should contain a list of dispatch functions
;; each of which will be tried in turn and given a chance to return
;; either a handler or nil. The dispatch functions will have access
;; to the`ss-request' variable through the following functions
;; - `ss-request-host' returns the host name of the request
;; - `ss-request-method' returns the method as a keyword i.e. :get
;; - `ss-request-uri' returns the path of the uri following the
;; hostname and port etc...
;; handlers
;; A handler is a function which will be called with no arguments (but
;; does have access to the request functions mentioned above) and
;; should return a HTTP string which will be passed back to the
;; client.
;; Hopefully one day it will parse get parameters and handle post
;; requests.
;;; Code:
;; require statements
(defvar ss-clients '()
"alist where KEY is a client process and VALUE is the string")
(defvar ss-name "web-server")
(defvar ss-buffer "*web-server*")
(defvar ss-log "*simple-server-log*")
(defvar ss-host 'local)
(defvar ss-default-404-page
"<html><head><title>404</title></head><body><center><h2>404 Not Found</h2></center></body></html>")
(defvar ss-request
`((host . ,ss-host)
(method . nil)
(uri . nil))
"The request object which will be set by each incomming http
request, and should only be accessed through the
`ss-request-host', `ss-request-method', and `ss-request-uri'
functions." )
(defvar ss-http-headers
'((status . 200)
(connection . "close")
(type . "html")
(server . "Emacs/simple-server.el"))
"Alist of http headers")
(defvar ss-http-status-codes
'((200 . "OK")
(301 . "Moved permanently")
(302 . "Moved temporarily")
(400 . "Bad request")
(403 . "Forbidden")
(404 . "Not found")
(405 . "Method not allowed")
(500 . "Internal server error")
(501 . "Not implemented")
(503 . "Service unavailable"))
"Alist of http status codes and their meanings")
(defvar ss-mime-types
'(("html" . "text/html; charset=utf-8")
("txt" . "text/plain; charset=utf-8")
("css" . "text/css")
("jpg" . "image/jpeg")
("jpeg" . "image/jpeg")
("gif" . "image/gif")
("png" . "image/png")
("tif" . "image/tiff")
("tiff" . "image/tiff")
("gz" . "application/octet-stream")
("ps" . "application/postscript")
("pdf" . "application/pdf")
("eps" . "application/postscript")
("tar" . "application/x-tar")
("rpm" . "application/x-rpm")
("zip" . "application/zip")
("mp3" . "audio/mpeg")
("mp2" . "audio/mpeg")
("mid" . "audio/midi")
("midi" . "audio/midi")
("wav" . "audio/x-wav")
("au" . "audio/basic")
("ram" . "audio/pn-realaudio")
("ra" . "audio/x-realaudio")
("mpg" . "video/mpeg")
("mpeg" . "video/mpeg")
("qt" . "video/quicktime")
("mov" . "video/quicktime")
("avi" . "video/x-msvideo")))
(defvar ss-default-page
"<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"
<html xmlns=\"\" xml:lang=\"en\" lang=\"en\">
<head><title>Simple Server is up and running</title></head>
<body><h2>Simple Server</h2>
<p><b>Simple Server</b> is a VERY simple web-server written entirely<br>
in emacs lisp. This is made possible thanks to the addition of<br>
server-sockets to emacs via the `make-network-process' command.<br></p>
<p>I would not recommend actually using this in anything even<br>
resembling a production environment.</p></body></html>\n")
(defvar ss-dispatch-table
'((lambda ()
(if (string-equal "/" (ss-request-uri)) (lambda () ss-default-page) nil)))
"List of functions which accept the route of the request, and
then return a page. If a function returns nil, then the next
function on the list is called. These functions are tried in
order. The last function on the list should render the default
;;; Control Functions:
(defun simple-server-start ()
"Starts a simple emacs webserver"
(unless (process-status ss-name)
(make-network-process :name ss-name
:host ss-host
:buffer ss-buffer
:family 'ipv4
:service 3000
:sentinel 'ss-sentinel
:filter 'ss-filter
:server 't)
(setq echo-server-clients '())))
(defun simple-server-stop ()
"stop an emacs simple server"
(while ss-clients
(delete-process (car (car ss-clients)))
(setq ss-clients (cdr ss-clients)))
(delete-process ss-name))
(defun simple-server-toggle ()
"turn the simple-server on or off"
(if (process-status ss-name) (simple-server-stop) (simple-server-start)))
(defun simple-server-restart ()
"restart the emacs simple server"
(interactive) (simple-server-stop) (simple-server-start))
;;; Process Implementation:
(defun ss-filter (proc string)
(let ((pending (assoc proc ss-clients))
message index responce)
;;create entry if required
(unless pending
(setq ss-clients (cons (cons proc "") ss-clients))
(setq pending (assoc proc ss-clients)))
(setq message (concat (cdr pending) string))
(while (setq index (string-match "\n" message)) ;; this is the main server loop
;; collect the request
(setq index (1+ index))
(ss-log (substring message 0 index) "in" proc)
;; find the route
(when (string-match "GET \\([^ ]+\\) HTTP" message)
(setf (cdr (assoc 'uri ss-request)) (match-string 1 message))
(ss-log (ss-request-uri) "uri"))
;; when the request ends reply
(when (string-equal "\r\n" message)
(process-send-string proc (ss-serve))
(unless (string= "keep-alive" (ss-get-header 'connection))
(delete-process proc)))
(setq message (substring message index)))
(setcdr pending message)))
(defun ss-sentinel (proc msg)
(delq proc ss-clients)
(ss-log (format "client %s has quit" proc) "quit"))
(defun ss-log (string type &optional client)
"If a *simple-server* buffer exists, write STRING to it for logging purposes."
(if (get-buffer ss-log)
(with-current-buffer ss-log
(goto-char (point-max))
(insert type
(if client (format " %s:" client) " ")
(or (bolp) (newline)))))
(defun ss-create-log ()
(get-buffer-create ss-log))
;;; Utility Functions:
(defun ss-request-host ()
"returns the host name of the request"
(cdr (assoc 'host ss-request)))
(defun ss-request-method ()
"returns the method as a keyword i.e. :get"
(cdr (assoc 'method ss-request)))
(defun ss-request-uri ()
"returns the path of the uri following the"
(cdr (assoc 'uri ss-request)))
(defun ss-set-header (header value)
(let ((pair (assoc header ss-http-headers)))
(setf (cdr pair) value)))
(defun ss-reset-http-headers ()
(mapcar (lambda (pair)
(ss-set-header (car pair) (cdr pair)))
'((status . 200)
(connection . "close")
(type . "html")
(server . "Emacs/simple-server.el"))))
(defun ss-get-header (header)
(cdr (assoc header ss-http-headers)))
(defun ss-expand-status (code)
(cdr (assoc code ss-http-status-codes)))
(defun ss-expand-mime (mime-type)
(cdr (assoc mime-type ss-mime-types)))
(defun ss-http-header (&optional content-length)
"Return a string of the http header based upon the contents of
(let* ((endl "\r\n")
(status (ss-get-header 'status))
(long-status (ss-expand-status status))
(status-str (int-to-string status))
(connection (ss-get-header 'connection))
(type (ss-get-header 'type))
(long-type (ss-expand-mime type))
(server (ss-get-header 'server))
(date (format-time-string "%a, %d %b %Y %H:%M:%S %Z")))
"HTTP/1.1 " status-str " " long-status endl
"Connection: " connection endl
"Date: " date endl
"Status: " status-str " " long-status endl
"Server: " server endl
"Content-Type: " long-type endl
(if content-length (format "Content-Length: %d%s" content-length endl))
(defun ss-serve ()
"This function cycles through the functions in the
`ss-dispatch-table' until one returns a handler. The handler is
then called and the result is wrapped in header information and
passed to the http client.
Default header information is specified in `ss-reset-http-headers'.
To change header information a handler should change the values
of `ss-http-headers' using `ss-set-header'."
(let (handler result)
(dolist (dispatcher ss-dispatch-table)
(when (null handler)
(setf handler (funcall dispatcher))))
(if (and handler (setf result (funcall handler)))
(ss-log (ss-http-header (length result)) "header:\n")
(concat (ss-http-header (length result)) result))
(concat (and (ss-set-header 'status 404) (ss-http-header) ss-default-404-page)))))
(provide 'simple-server)
;;; simple-server.el ends here
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