Wilfred/show-your-colors.el

## show-your-colors.el
;;; show-your-colours --- an HTTP server showing the current buffer fontified

;; Author: Wilfred Hughes <me@wilfred.me.uk>
;; Version: 0.1
;; Package-Requires: ((s "1.3.0"))

;;; Commentary:

;; Allow others to see what you're editing in Emacs. For live
;; screencasts, or general Emacs advocacy. If you have multiple
;; buffers open, this will show the currently focused buffer.

;; FIXME: Crashes with rainbow-delimeters.

(require 'elnode)
(require 's)

(defvar show-your-colours-buffer nil
  "The buffer currently being visited by the user.")

(defvar syc--port 9000)

;; todo: wrap this in a minor mode
(defadvice ido-switch-buffer (after set-syc--buffer)
  "Set `syc--buffer' to the current buffer.
Since `switch-to-buffer' is very low-level and used everywhere,
we assume a buffer change by a user always uses `ido-switch-buffer"
  (setq syc--buffer (current-buffer)))

;; todo: is there a way we can just activate our advice?
(ad-activate 'ido-switch-buffer)

(defadvice other-window (after set-syc--buffer)
  "Set `syc--buffer' to the current buffer.
Since `switch-to-buffer' is very low-level and used everywhere,
we assume a buffer change by a user always uses `ido-switch-buffer"
  (setq syc--buffer (current-buffer)))

;; todo: is there a way we can just activate our advice?
(ad-activate 'other-window)

;; todo: automatic reload
(defun syc--buffer-as-html ()
  "Get the current buffer and return a string of HTML.
The HTML is styled according to the buffer's fontification."
  ;; htmlize-buffer calls message, stop that
  (flet ((message (&rest args)))
    (condition-case nil
        (let ((htmlize-buffer (htmlize-buffer syc--buffer))
              html)
          (save-excursion
            (switch-to-buffer htmlize-buffer)
            (setq html
                  (buffer-substring-no-properties (point-min) (point-max)))
            (kill-buffer htmlize-buffer))
          html)
        (error "<html><body>Could not fontify buffer.</body></html>"))))

(defun syc--append-reload (html)
  "Given a piece of HTML, return a new string with
a JS automatic reload script appended."
  (s-replace
   "</body>"
   "<script type=\"text/javascript\">setTimeout(function() { location.reload(true); }, 1000);</script>
</body>"
   html))

;; todo: why can't I let-bind this inside syc--handler?
(setq elnode-error-log-to-messages nil)

(defun syc--handler (httpcon)
  (elnode-http-start httpcon 200 '("Content-Type" . "text/html"))
  (elnode-http-return
   httpcon
   (syc--append-reload
    (syc--buffer-as-html))))

(elnode-start 'syc--handler :port syc--port :host "localhost")
	;;; show-your-colours --- an HTTP server showing the current buffer fontified

	;; Author: Wilfred Hughes <me@wilfred.me.uk>
	;; Version: 0.1
	;; Package-Requires: ((s "1.3.0"))

	;;; Commentary:

	;; Allow others to see what you're editing in Emacs. For live
	;; screencasts, or general Emacs advocacy. If you have multiple
	;; buffers open, this will show the currently focused buffer.

	;; FIXME: Crashes with rainbow-delimeters.

	(require 'elnode)
	(require 's)

	(defvar show-your-colours-buffer nil
	"The buffer currently being visited by the user.")

	(defvar syc--port 9000)

	;; todo: wrap this in a minor mode
	(defadvice ido-switch-buffer (after set-syc--buffer)
	"Set `syc--buffer' to the current buffer.
	Since `switch-to-buffer' is very low-level and used everywhere,
	we assume a buffer change by a user always uses `ido-switch-buffer"
	(setq syc--buffer (current-buffer)))

	;; todo: is there a way we can just activate our advice?
	(ad-activate 'ido-switch-buffer)

	(defadvice other-window (after set-syc--buffer)
	"Set `syc--buffer' to the current buffer.
	Since `switch-to-buffer' is very low-level and used everywhere,
	we assume a buffer change by a user always uses `ido-switch-buffer"
	(setq syc--buffer (current-buffer)))

	;; todo: is there a way we can just activate our advice?
	(ad-activate 'other-window)

	;; todo: automatic reload
	(defun syc--buffer-as-html ()
	"Get the current buffer and return a string of HTML.
	The HTML is styled according to the buffer's fontification."
	;; htmlize-buffer calls message, stop that
	(flet ((message (&rest args)))
	(condition-case nil
	(let ((htmlize-buffer (htmlize-buffer syc--buffer))
	html)
	(save-excursion
	(switch-to-buffer htmlize-buffer)
	(setq html
	(buffer-substring-no-properties (point-min) (point-max)))
	(kill-buffer htmlize-buffer))
	html)
	(error "<html><body>Could not fontify buffer.</body></html>"))))

	(defun syc--append-reload (html)
	"Given a piece of HTML, return a new string with
	a JS automatic reload script appended."
	(s-replace
	"</body>"
	"<script type=\"text/javascript\">setTimeout(function() { location.reload(true); }, 1000);</script>
	</body>"
	html))

	;; todo: why can't I let-bind this inside syc--handler?
	(setq elnode-error-log-to-messages nil)

	(defun syc--handler (httpcon)
	(elnode-http-start httpcon 200 '("Content-Type" . "text/html"))
	(elnode-http-return
	httpcon
	(syc--append-reload
	(syc--buffer-as-html))))

	(elnode-start 'syc--handler :port syc--port :host "localhost")