lisp/image/gravatar.el

   1 ;;; gravatar.el --- Get Gravatars
   2
   3 ;; Copyright (C) 2010-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Julien Danjou <julien@danjou.info>
   6 ;; Keywords: news
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (require 'url)
  28 (require 'url-cache)
  29 (require 'image)
  30
  31 (defgroup gravatar nil
  32   "Gravatar."
  33   :version "24.1"
  34   :group 'comm)
  35
  36 (defcustom gravatar-automatic-caching t
  37   "Whether to cache retrieved gravatars."
  38   :type 'boolean
  39   :group 'gravatar)
  40
  41 ;; FIXME a time value is not the nicest format for a custom variable.
  42 (defcustom gravatar-cache-ttl (days-to-time 30)
  43   "Time to live for gravatar cache entries."
  44   :type '(repeat integer)
  45   :group 'gravatar)
  46
  47 ;; FIXME Doc is tautological.  What are the options?
  48 (defcustom gravatar-rating "g"
  49   "Default rating for gravatar."
  50   :type 'string
  51   :group 'gravatar)
  52
  53 (defcustom gravatar-size 32
  54   "Default size in pixels for gravatars."
  55   :type 'integer
  56   :group 'gravatar)
  57
  58 (defconst gravatar-base-url
  59   "http://www.gravatar.com/avatar"
  60   "Base URL for getting gravatars.")
  61
  62 (defun gravatar-hash (mail-address)
  63   "Create an hash from MAIL-ADDRESS."
  64   (md5 (downcase mail-address)))
  65
  66 (defun gravatar-build-url (mail-address)
  67   "Return an URL to retrieve MAIL-ADDRESS gravatar."
  68   (format "%s/%s?d=404&r=%s&s=%d"
  69           gravatar-base-url
  70           (gravatar-hash mail-address)
  71           gravatar-rating
  72           gravatar-size))
  73
  74 (defun gravatar-cache-expired (url)
  75   "Check if URL is cached for more than `gravatar-cache-ttl'."
  76   (cond (url-standalone-mode
  77          (not (file-exists-p (url-cache-create-filename url))))
  78         (t (let ((cache-time (url-is-cached url)))
  79              (if cache-time
  80                  (time-less-p
  81                   (time-add
  82                    cache-time
  83                    gravatar-cache-ttl)
  84                   (current-time))
  85                t)))))
  86
  87 (defun gravatar-get-data ()
  88   "Get data from current buffer."
  89   (save-excursion
  90     (goto-char (point-min))
  91     (when (re-search-forward "^HTTP/.+ 200 OK$" nil (line-end-position))
  92       (when (search-forward "\n\n" nil t)
  93         (buffer-substring (point) (point-max))))))
  94
  95 (defun gravatar-data->image ()
  96   "Get data of current buffer and return an image.
  97 If no image available, return 'error."
  98   (let ((data (gravatar-get-data)))
  99     (if data
 100         (create-image data nil t)
 101       'error)))
 102
 103 (autoload 'help-function-arglist "help-fns")
 104
 105 ;;;###autoload
 106 (defun gravatar-retrieve (mail-address cb &optional cbargs)
 107   "Retrieve MAIL-ADDRESS gravatar and call CB on retrieval.
 108 You can provide a list of argument to pass to CB in CBARGS."
 109   (let ((url (gravatar-build-url mail-address)))
 110     (if (gravatar-cache-expired url)
 111         (let ((args (list url
 112                           'gravatar-retrieved
 113                           (list cb (when cbargs cbargs)))))
 114           (when (> (length (if (featurep 'xemacs)
 115                                (cdr (split-string (function-arglist 'url-retrieve)))
 116                              (help-function-arglist 'url-retrieve)))
 117                    4)
 118             (setq args (nconc args (list t))))
 119           (apply #'url-retrieve args))
 120       (apply cb
 121                (with-temp-buffer
 122                  (set-buffer-multibyte nil)
 123                  (url-cache-extract (url-cache-create-filename url))
 124                  (gravatar-data->image))
 125                cbargs))))
 126
 127 ;;;###autoload
 128 (defun gravatar-retrieve-synchronously (mail-address)
 129   "Retrieve MAIL-ADDRESS gravatar and returns it."
 130   (let ((url (gravatar-build-url mail-address)))
 131     (if (gravatar-cache-expired url)
 132         (with-current-buffer (url-retrieve-synchronously url)
 133           (when gravatar-automatic-caching
 134             (url-store-in-cache (current-buffer)))
 135           (let ((data (gravatar-data->image)))
 136             (kill-buffer (current-buffer))
 137             data))
 138       (with-temp-buffer
 139         (set-buffer-multibyte nil)
 140         (url-cache-extract (url-cache-create-filename url))
 141         (gravatar-data->image)))))
 142
 143
 144 (defun gravatar-retrieved (status cb &optional cbargs)
 145   "Callback function used by `gravatar-retrieve'."
 146   ;; Store gravatar?
 147   (when gravatar-automatic-caching
 148     (url-store-in-cache (current-buffer)))
 149   (if (plist-get status :error)
 150       ;; Error happened.
 151       (apply cb 'error cbargs)
 152     (apply cb (gravatar-data->image) cbargs))
 153   (kill-buffer (current-buffer)))
 154
 155 (provide 'gravatar)
 156
 157 ;;; gravatar.el ends here