core/http_api.php

   1 <?php
   2 # MantisBT - A PHP based bugtracking system
   3
   4 # MantisBT is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation, either version 2 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # MantisBT is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with MantisBT.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * HTTP API
  19  *
  20  * Provides functions to manage HTTP response headers.
  21  *
  22  * @package CoreAPI
  23  * @subpackage HTTPAPI
  24  * @copyright Copyright (C) 2002 - 2010  MantisBT Team - mantisbt-dev@lists.sourceforge.net
  25  * @link http://www.mantisbt.org
  26  *
  27  * @uses config_api.php
  28  */
  29
  30 require_api( 'config_api.php' );
  31
  32 /**
  33  * Check to see if the client is using Microsoft Internet Explorer so we can
  34  * enable quirks and hacky non-standards-compliant workarounds.
  35  * @return boolean True if Internet Explorer is detected as the user agent
  36  */
  37 function is_browser_internet_explorer() {
  38         $t_user_agent = isset( $_SERVER['HTTP_USER_AGENT'] ) ? $_SERVER['HTTP_USER_AGENT'] : 'none';
  39
  40         if ( strpos( $t_user_agent, 'MSIE' ) ) {
  41                 return true;
  42         }
  43
  44         return false;
  45 }
  46
  47 /**
  48  * Checks to see if the client is using Google Chrome so we can enable quirks
  49  * and hacky non-standards-compliant workarounds.
  50  * @return boolean True if Chrome is detected as the user agent
  51  */
  52 function is_browser_chrome() {
  53         $t_user_agent = isset( $_SERVER['HTTP_USER_AGENT'] ) ? $_SERVER['HTTP_USER_AGENT'] : 'none';
  54
  55         if ( strpos( $t_user_agent, 'Chrome/' ) ) {
  56                 return true;
  57         }
  58
  59         return false;
  60 }
  61
  62 /**
  63  * Send a Content-Disposition header. This is more complex than it sounds
  64  * because only a few browsers properly support RFC2231. For those browsers
  65  * which are behind the times or are otherwise broken, we need to use
  66  * some hacky workarounds to get them to work 'nicely' with attachments and
  67  * inline files. See http://greenbytes.de/tech/tc2231/ for full reasoning.
  68  * @param string Filename
  69  * @param boolean Display file inline (optional, default = treat as attachment)
  70  */
  71 function http_content_disposition_header( $p_filename, $p_inline = false ) {
  72         if ( !headers_sent() ) {
  73                 $t_encoded_filename = rawurlencode( $p_filename );
  74                 $t_disposition = '';
  75                 if ( !$p_inline ) {
  76                         $t_disposition = 'attachment;';
  77                 }
  78                 if ( is_browser_internet_explorer() || is_browser_chrome() ) {
  79                         // Internet Explorer does not support RFC2231 however it does
  80                         // incorrectly decode URL encoded filenames and we can use this to
  81                         // get UTF8 filenames to work with the file download dialog. Chrome
  82                         // behaves in the same was as Internet Explorer in this respect.
  83                         // See http://greenbytes.de/tech/tc2231/#attwithfnrawpctenclong
  84                         header( 'Content-Disposition:' . $t_disposition . ' filename="' . $t_encoded_filename . '"' );
  85                 } else {
  86                         // For most other browsers, we can use this technique:
  87                         // http://greenbytes.de/tech/tc2231/#attfnboth2
  88                         header( 'Content-Disposition:' . $t_disposition . ' filename*=UTF-8\'\'' . $t_encoded_filename . '; filename="' . $t_encoded_filename . '"' );
  89                 }
  90         }
  91 }
  92
  93 /**
  94  * Set caching headers that will allow or prevent browser caching.
  95  * @param boolean Allow caching
  96  */
  97 function http_caching_headers( $p_allow_caching=false ) {
  98         global $g_allow_browser_cache;
  99
 100         // Headers to prevent caching
 101         // with option to bypass if running from script
 102         if ( !headers_sent() ) {
 103                 if ( $p_allow_caching || ( isset( $g_allow_browser_cache ) && ON == $g_allow_browser_cache ) ) {
 104                         if ( is_browser_internet_explorer() ) {
 105                                 header( 'Cache-Control: private, proxy-revalidate' );
 106                         } else {
 107                                 header( 'Cache-Control: private, must-revalidate' );
 108                         }
 109                 } else {
 110                         header( 'Cache-Control: no-store, no-cache, must-revalidate' );
 111                 }
 112
 113                 header( 'Expires: ' . gmdate( 'D, d M Y H:i:s \G\M\T', time() ) );
 114                 header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s \G\M\T', time() ) );
 115         }
 116 }
 117
 118 /**
 119  * Set content-type headers.
 120  */
 121 function http_content_headers() {
 122         if ( !headers_sent() ) {
 123                 header( 'Content-type: text/html;charset=utf-8' );
 124         }
 125 }
 126
 127 /**
 128  * Load and set any custom headers defined by the site configuration.
 129  */
 130 function http_custom_headers() {
 131         if ( !headers_sent() ) {
 132                 // send user-defined headers
 133                 foreach( config_get_global( 'custom_headers' ) as $t_header ) {
 134                         header( $t_header );
 135                 }
 136         }
 137 }
 138
 139 /**
 140  * Set all headers used by a normal page load.
 141  */
 142 function http_all_headers() {
 143         global $g_bypass_headers;
 144
 145         if ( !$g_bypass_headers && !headers_sent() ) {
 146                 http_content_headers();
 147                 http_caching_headers();
 148                 http_custom_headers();
 149         }
 150 }