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1 ;;; url-cache.el --- Uniform Resource Locator retrieval tool
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2 ;; Author: wmperry
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118
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3 ;; Created: 1997/04/03 21:04:08
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4 ;; Version: 1.11
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5 ;; Keywords: comm, data, processes, hypermedia
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6
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7 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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8 ;;; Copyright (c) 1993-1996 by William M. Perry (wmperry@cs.indiana.edu)
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9 ;;; Copyright (c) 1996, 1997 Free Software Foundation, Inc.
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10 ;;;
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11 ;;; This file is not part of GNU Emacs, but the same permissions apply.
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12 ;;;
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13 ;;; GNU Emacs is free software; you can redistribute it and/or modify
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14 ;;; it under the terms of the GNU General Public License as published by
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15 ;;; the Free Software Foundation; either version 2, or (at your option)
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16 ;;; any later version.
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17 ;;;
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18 ;;; GNU Emacs is distributed in the hope that it will be useful,
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19 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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20 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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21 ;;; GNU General Public License for more details.
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22 ;;;
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23 ;;; You should have received a copy of the GNU General Public License
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24 ;;; along with GNU Emacs; see the file COPYING. If not, write to the
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25 ;;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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26 ;;; Boston, MA 02111-1307, USA.
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27 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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28 (require 'md5)
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29
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30
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30 (defvar url-cache-directory "~/.w3/cache/"
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31 "*The directory where cache files should be stored.")
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32
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26
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33 ;; Cache manager
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34 (defun url-cache-file-writable-p (file)
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35 "Follows the documentation of file-writable-p, unlike file-writable-p."
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36 (and (file-writable-p file)
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37 (if (file-exists-p file)
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38 (not (file-directory-p file))
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39 (file-directory-p (file-name-directory file)))))
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40
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30
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41 (defun url-cache-prepare (file)
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26
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42 "Makes it possible to cache data in FILE.
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43 Creates any necessary parent directories, deleting any non-directory files
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44 that would stop this. Returns nil if parent directories can not be
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45 created. If FILE already exists as a non-directory, it changes
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46 permissions of FILE or deletes FILE to make it possible to write a new
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47 version of FILE. Returns nil if this can not be done. Returns nil if
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48 FILE already exists as a directory. Otherwise, returns t, indicating that
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49 FILE can be created or overwritten."
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50 (cond
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51 ((url-cache-file-writable-p file)
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52 t)
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53 ((file-directory-p file)
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54 nil)
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55 (t
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32
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56 (condition-case ()
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57 (or (make-directory (file-name-directory file) t) t)
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58 (error nil)))))
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26
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59
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60 (defvar url-cache-ignored-protocols
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61 '("www" "about" "https" "mailto")
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62 "*A list of protocols that we should never cache.")
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63
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64 (defun url-cache-cachable-p (obj)
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65 ;; return t iff the current buffer is cachable
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66 (cond
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32
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67 ((not url-automatic-caching) ; User doesn't want to cache
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68 nil)
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26
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69 ((null obj) ; Something horribly confused
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70 nil)
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71 ((member (url-type obj) url-cache-ignored-protocols)
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72 ;; We have been told to ignore this type of object
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73 nil)
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74 ((and (member (url-type obj) '("file" "ftp")) (not (url-host obj)))
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75 ;; We never want to cache local files... what's the point?
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76 nil)
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77 ((member (url-type obj) '("http" "https"))
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78 (let* ((status (cdr-safe (assoc "status" url-current-mime-headers)))
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79 (class (if status (/ status 100) 0)))
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30
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80 (cond
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81 ((string-match (eval-when-compile (regexp-quote "?"))
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82 (url-filename obj))
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83 nil)
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84 ((= class 2)
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85 (memq status '(200)))
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86 (t nil))))
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26
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87 (t
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88 nil)))
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89
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90 ;;;###autoload
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91 (defun url-store-in-cache (&optional buff)
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92 "Store buffer BUFF in the cache"
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30
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93 (if (not (and buff (get-buffer buff)))
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94 nil
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95 (save-excursion
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96 (and buff (set-buffer buff))
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97 (if (not (url-cache-cachable-p url-current-object))
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98 nil
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99 (let* ((fname (url-cache-create-filename (url-view-url t)))
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100 (fname-hdr (concat fname ".hdr"))
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101 (info (mapcar (function (lambda (var)
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102 (cons (symbol-name var)
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103 (symbol-value var))))
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104 '( url-current-content-length
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105 url-current-object
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106 url-current-isindex
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107 url-current-mime-encoding
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108 url-current-mime-headers
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109 url-current-mime-type
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110 ))))
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111 (cond ((and (url-cache-prepare fname)
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112 (url-cache-prepare fname-hdr))
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113 (write-region (point-min) (point-max) fname nil 5)
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114 (set-buffer (get-buffer-create " *cache-tmp*"))
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115 (erase-buffer)
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116 (insert "(setq ")
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117 (mapcar
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118 (function
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119 (lambda (x)
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120 (insert (car x) " "
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121 (cond ((null (setq x (cdr x))) "nil")
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122 ((stringp x) (prin1-to-string x))
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123 ((listp x) (concat "'" (prin1-to-string x)))
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124 ((vectorp x) (prin1-to-string x))
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125 ((numberp x) (int-to-string x))
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126 (t "'???")) "\n")))
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127 info)
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128 (insert ")\n")
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129 (write-region (point-min) (point-max) fname-hdr nil 5))))))))
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130
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131
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132 ;;;###autoload
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133 (defun url-is-cached (url)
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134 "Return non-nil if the URL is cached."
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135 (let* ((fname (url-cache-create-filename url))
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136 (attribs (file-attributes fname)))
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137 (and fname ; got a filename
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138 (file-exists-p fname) ; file exists
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139 (not (eq (nth 0 attribs) t)) ; Its not a directory
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140 (nth 5 attribs)))) ; Can get last mod-time
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141
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142 (defun url-cache-create-filename-human-readable (url)
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143 "Return a filename in the local cache for URL"
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144 (if url
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145 (let* ((url (if (vectorp url) (url-recreate-url url) url))
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146 (urlobj (url-generic-parse-url url))
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147 (protocol (url-type urlobj))
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148 (hostname (url-host urlobj))
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149 (host-components
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150 (cons
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151 (user-real-login-name)
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152 (cons (or protocol "file")
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118
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153 (reverse (split-string (or hostname "localhost")
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154 (eval-when-compile
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155 (regexp-quote ".")))))))
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156 (fname (url-filename urlobj)))
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157 (if (and fname (/= (length fname) 0) (= (aref fname 0) ?/))
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158 (setq fname (substring fname 1 nil)))
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159 (if fname
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160 (let ((slash nil))
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161 (setq fname
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162 (mapconcat
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163 (function
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164 (lambda (x)
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165 (cond
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166 ((and (= ?/ x) slash)
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167 (setq slash nil)
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168 "%2F")
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169 ((= ?/ x)
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170 (setq slash t)
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171 "/")
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172 (t
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173 (setq slash nil)
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174 (char-to-string x))))) fname ""))))
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175
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176 (setq fname (and fname
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177 (mapconcat
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178 (function (lambda (x)
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179 (if (= x ?~) "" (char-to-string x))))
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180 fname ""))
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181 fname (cond
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182 ((null fname) nil)
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183 ((or (string= "" fname) (string= "/" fname))
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184 url-directory-index-file)
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185 ((= (string-to-char fname) ?/)
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186 (if (string= (substring fname -1 nil) "/")
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187 (concat fname url-directory-index-file)
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188 (substring fname 1 nil)))
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189 (t
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190 (if (string= (substring fname -1 nil) "/")
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191 (concat fname url-directory-index-file)
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192 fname))))
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193 (and fname
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194 (expand-file-name fname
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195 (expand-file-name
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196 (mapconcat 'identity host-components "/")
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197 url-cache-directory))))))
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198
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199 (defun url-cache-create-filename-using-md5 (url)
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200 "Create a cached filename using MD5.
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201 Very fast if you are in XEmacs, suitably fast otherwise."
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202 (if url
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203 (let* ((checksum (md5 url))
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204 (url (if (vectorp url) (url-recreate-url url) url))
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205 (urlobj (url-generic-parse-url url))
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206 (protocol (url-type urlobj))
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207 (hostname (url-host urlobj))
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208 (host-components
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209 (cons
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210 (user-real-login-name)
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211 (cons (or protocol "file")
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212 (nreverse
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213 (delq nil
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214 (split-string (or hostname "localhost")
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215 (eval-when-compile
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216 (regexp-quote "."))))))))
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217 (fname (url-filename urlobj)))
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218 (and fname
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219 (expand-file-name checksum
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220 (expand-file-name
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221 (mapconcat 'identity host-components "/")
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222 url-cache-directory))))))
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223
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224 (defvar url-cache-creation-function 'url-cache-create-filename-using-md5
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225 "*What function to use to create a cached filename.")
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226
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227 (defun url-cache-create-filename (url)
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228 (funcall url-cache-creation-function url))
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229
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230 ;;;###autoload
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231 (defun url-cache-extract (fnam)
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232 "Extract FNAM from the local disk cache"
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233 (set-buffer (get-buffer-create url-working-buffer))
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234 (erase-buffer)
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235 (setq url-current-mime-viewer nil)
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236 (insert-file-contents-literally fnam)
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237 (load (concat (if (memq system-type '(ms-windows ms-dos os2))
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238 (url-file-extension fnam t)
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239 fnam) ".hdr") t t))
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240
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241 ;;;###autoload
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242 (defun url-cache-expired (url mod)
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243 "Return t iff a cached file has expired."
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32
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244 (let* ((urlobj (if (vectorp url) url (url-generic-parse-url url)))
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245 (type (url-type urlobj)))
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246 (cond
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247 (url-standalone-mode
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248 (not (file-exists-p (url-cache-create-filename url))))
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249 ((string= type "http")
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250 t)
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251 ((member type '("file" "ftp"))
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252 (if (or (equal mod '(0 0)) (not mod))
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253 (return t)
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254 (or (> (nth 0 mod) (nth 0 (current-time)))
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255 (> (nth 1 mod) (nth 1 (current-time))))))
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256 (t nil))))
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257
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258 (provide 'url-cache)
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