1 ;;; url-cache.el --- Uniform Resource Locator retrieval tool
3 ;; Copyright (C) 1996, 1997, 1998, 1999, 2004,
4 ;; 2005, 2006, 2007 Free Software Foundation, Inc.
6 ;; Keywords: comm, data, processes, hypermedia
8 ;; This file is part of GNU Emacs.
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 2, or (at your option)
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.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
23 ;; Boston, MA 02110-1301, USA.
29 (require 'url) ;E.g. for url-configuration-directory.
31 (defcustom url-cache-directory
32 (expand-file-name "cache" url-configuration-directory)
33 "*The directory where cache files should be stored."
38 (defun url-cache-file-writable-p (file)
39 "Follows the documentation of `file-writable-p', unlike `file-writable-p'."
40 (and (file-writable-p file)
41 (if (file-exists-p file)
42 (not (file-directory-p file))
43 (file-directory-p (file-name-directory file)))))
45 (defun url-cache-prepare (file)
46 "Makes it possible to cache data in FILE.
47 Creates any necessary parent directories, deleting any non-directory files
48 that would stop this. Returns nil if parent directories can not be
49 created. If FILE already exists as a non-directory, it changes
50 permissions of FILE or deletes FILE to make it possible to write a new
51 version of FILE. Returns nil if this can not be done. Returns nil if
52 FILE already exists as a directory. Otherwise, returns t, indicating that
53 FILE can be created or overwritten."
55 ((url-cache-file-writable-p file)
57 ((file-directory-p file)
61 (or (make-directory (file-name-directory file) t) t)
65 (defun url-store-in-cache (&optional buff)
66 "Store buffer BUFF in the cache."
67 (if (not (and buff (get-buffer buff)))
70 (and buff (set-buffer buff))
71 (let* ((fname (url-cache-create-filename (url-view-url t))))
72 (if (url-cache-prepare fname)
73 (let ((coding-system-for-write 'binary))
74 (write-region (point-min) (point-max) fname nil 5)))))))
77 (defun url-is-cached (url)
78 "Return non-nil if the URL is cached."
79 (let* ((fname (url-cache-create-filename url))
80 (attribs (file-attributes fname)))
81 (and fname ; got a filename
82 (file-exists-p fname) ; file exists
83 (not (eq (nth 0 attribs) t)) ; Its not a directory
84 (nth 5 attribs)))) ; Can get last mod-time
86 (defun url-cache-create-filename-human-readable (url)
87 "Return a filename in the local cache for URL"
89 (let* ((url (if (vectorp url) (url-recreate-url url) url))
90 (urlobj (url-generic-parse-url url))
91 (protocol (url-type urlobj))
92 (hostname (url-host urlobj))
95 (user-real-login-name)
96 (cons (or protocol "file")
97 (reverse (split-string (or hostname "localhost")
99 (regexp-quote ".")))))))
100 (fname (url-filename urlobj)))
101 (if (and fname (/= (length fname) 0) (= (aref fname 0) ?/))
102 (setq fname (substring fname 1 nil)))
110 ((and (= ?/ x) slash)
118 (char-to-string x))))) fname ""))))
120 (setq fname (and fname
122 (function (lambda (x)
123 (if (= x ?~) "" (char-to-string x))))
127 ((or (string= "" fname) (string= "/" fname))
128 url-directory-index-file)
129 ((= (string-to-char fname) ?/)
130 (if (string= (substring fname -1 nil) "/")
131 (concat fname url-directory-index-file)
132 (substring fname 1 nil)))
134 (if (string= (substring fname -1 nil) "/")
135 (concat fname url-directory-index-file)
138 (expand-file-name fname
140 (mapconcat 'identity host-components "/")
141 url-cache-directory))))))
143 (defun url-cache-create-filename-using-md5 (url)
144 "Create a cached filename using MD5.
145 Very fast if you have an `md5' primitive function, suitably fast otherwise."
148 (let* ((url (if (vectorp url) (url-recreate-url url) url))
150 (urlobj (url-generic-parse-url url))
151 (protocol (url-type urlobj))
152 (hostname (url-host urlobj))
155 (user-real-login-name)
156 (cons (or protocol "file")
159 (split-string (or hostname "localhost")
161 (regexp-quote "."))))))))
162 (fname (url-filename urlobj)))
164 (expand-file-name checksum
166 (mapconcat 'identity host-components "/")
167 url-cache-directory))))))
169 (defcustom url-cache-creation-function 'url-cache-create-filename-using-md5
170 "*What function to use to create a cached filename."
171 :type '(choice (const :tag "MD5 of filename (low collision rate)"
172 :value url-cache-create-filename-using-md5)
173 (const :tag "Human readable filenames (higher collision rate)"
174 :value url-cache-create-filename-human-readable)
175 (function :tag "Other"))
178 (defun url-cache-create-filename (url)
179 (funcall url-cache-creation-function url))
182 (defun url-cache-extract (fnam)
183 "Extract FNAM from the local disk cache"
185 (insert-file-contents-literally fnam))
188 (defun url-cache-expired (url mod)
189 "Return t iff a cached file has expired."
190 (let* ((urlobj (if (vectorp url) url (url-generic-parse-url url)))
191 (type (url-type urlobj)))
194 (not (file-exists-p (url-cache-create-filename url))))
195 ((string= type "http")
197 ((member type '("file" "ftp"))
198 (if (or (equal mod '(0 0)) (not mod))
200 (or (> (nth 0 mod) (nth 0 (current-time)))
201 (> (nth 1 mod) (nth 1 (current-time))))))
206 ;; arch-tag: 95b050a6-8e81-4f23-8e63-191b9d1d657c
207 ;;; url-cache.el ends here