thumb_handler.php

   1 <?php
   2
   3 # Valid web server entry point
   4 define( 'THUMB_HANDLER', true );
   5
   6 # Load thumb-handler configuration. Avoids WebStart.php for performance.
   7 if ( !file_exists( dirname( __FILE__ ) . "/thumb.config.php" ) ) {
   8         die( "thumb_handler.php is not enabled for this wiki.\n" );
   9 }
  10 require( dirname( __FILE__ ) . "/thumb.config.php" );
  11
  12 # Execute thumb.php if not handled via cURL
  13 if ( wfHandleThumb404Main() === 'wfThumbMain' ) {
  14         require( dirname( __FILE__ ) . '/thumb.php' );
  15 }
  16
  17 function wfHandleThumb404Main() {
  18         global $thgThumbCallbacks, $thgThumbCurlConfig;
  19
  20         # lighttpd puts the original request in REQUEST_URI, while
  21         # sjs sets that to the 404 handler, and puts the original
  22         # request in REDIRECT_URL.
  23         if ( isset( $_SERVER['REDIRECT_URL'] ) ) {
  24                 # The URL is un-encoded, so put it back how it was.
  25                 $uri = str_replace( "%2F", "/", urlencode( $_SERVER['REDIRECT_URL'] ) );
  26         } else {
  27                 $uri = $_SERVER['REQUEST_URI'];
  28         }
  29
  30         # Extract thumb.php params from the URI...
  31         if ( isset( $thgThumbCallbacks['extractParams'] )
  32                 && is_callable( $thgThumbCallbacks['extractParams'] ) ) // overridden by configuration?
  33         {
  34                 $params = call_user_func_array( $thgThumbCallbacks['extractParams'], array( $uri ) );
  35         } else {
  36                 $params = wfExtractThumbParams( $uri ); // basic wiki URL param extracting
  37         }
  38
  39         # Show 404 error if this is not a valid thumb request...
  40         if ( !is_array( $params ) ) {
  41                 header( 'X-Debug: no regex match' ); // useful for debugging
  42                 if ( isset( $thgThumbCallbacks['error404'] )
  43                         && is_callable( $thgThumbCallbacks['error404'] ) ) // overridden by configuration?
  44                 {
  45                         call_user_func( $thgThumbCallbacks['error404'] );
  46                 } else {
  47                         wfDisplay404Error(); // standard 404 message
  48                 }
  49                 return;
  50         }
  51
  52         # Obtain and stream the thumbnail or setup for wfThumbMain() call...
  53         if ( $thgThumbCurlConfig['enabled'] ) {
  54                 wfStreamThumbViaCurl( $params, $uri );
  55                 return true; // done
  56         } else {
  57                 $_REQUEST = $params; // pass params to thumb.php
  58                 return 'wfThumbMain';
  59         }
  60 }
  61
  62 /**
  63  * Extract the required params for thumb.php from the thumbnail request URI.
  64  * At least 'width' and 'f' should be set if the result is an array.
  65  *
  66  * @param $uri String Thumbnail request URI
  67  * @return Array|null associative params array or null
  68  */
  69 function wfExtractThumbParams( $uri ) {
  70         global $thgThumbUrlMatch;
  71
  72         $thumbRegex = '!^(?:' . preg_quote( $thgThumbUrlMatch['server'] ) . ')?/' .
  73                 preg_quote( $thgThumbUrlMatch['dirFragment'] ) . '(/archive|/temp|)/' .
  74                 $thgThumbUrlMatch['hashFragment'] . '([^/]*)/(page(\d*)-)*(\d*)px-[^/]*$!';
  75
  76         if ( preg_match( $thumbRegex, $uri, $matches ) ) {
  77                 list( $all, $archOrTemp, $filename, $pagefull, $pagenum, $size ) = $matches;
  78                 $params = array( 'f' => $filename, 'width' => $size );
  79                 if ( $pagenum ) {
  80                         $params['page'] = $pagenum;
  81                 }
  82                 if ( $archOrTemp == '/archive' ) {
  83                         $params['archived'] = 1;
  84                 } elseif ( $archOrTemp == '/temp' ) {
  85                         $params['temp'] = 1;
  86                 }
  87         } else {
  88                 $params = null; // not a valid thumbnail URL
  89         }
  90
  91         return $params;
  92 }
  93
  94 /**
  95  * cURL to thumb.php and stream back the resulting file or give an error message.
  96  *
  97  * @param $params Array Parameters to thumb.php
  98  * @param $uri String Thumbnail request URI
  99  * @return void
 100  */
 101 function wfStreamThumbViaCurl( array $params, $uri ) {
 102         global $thgThumbCallbacks, $thgThumbCurlConfig;
 103
 104         # Check any backend caches for the thumbnail...
 105         if ( isset( $thgThumbCallbacks['checkCache'] )
 106                 && is_callable( $thgThumbCallbacks['checkCache'] ) )
 107         {
 108                 if ( call_user_func_array( $thgThumbCallbacks['checkCache'], array( $uri, $params ) ) ) {
 109                         return; // file streamed from backend thumb cache
 110                 }
 111         }
 112
 113         if ( !extension_loaded( 'curl' ) ) {
 114                 die( "cURL is not enabled for PHP on this wiki.\n" ); // sanity
 115         }
 116
 117         # Build up the request URL to use with CURL...
 118         $reqURL = $thgThumbCurlConfig['url'] . '?';
 119         $first = true;
 120         foreach ( $params as $name => $value ) {
 121                 if ( $first ) {
 122                         $first = false;
 123                 } else {
 124                         $reqURL .= '&';
 125                 }
 126                 $reqURL .= "$name=$value"; // Note: value is already urlencoded
 127         }
 128
 129         # Set relevant HTTP headers...
 130         $headers = array();
 131         $headers[] = "X-Original-URI: " . str_replace( "\n", '', $uri );
 132         if ( isset( $thgThumbCallbacks['curlHeaders'] )
 133                 && is_callable( $thgThumbCallbacks['curlHeaders'] ) )
 134         {
 135                 # Add on any custom headers (like XFF)
 136                 call_user_func_array( $thgThumbCallbacks['curlHeaders'], array( &$headers ) );
 137         }
 138
 139         # Pass through some other headers...
 140         $passThrough = array( 'If-Modified-Since', 'Referer', 'User-Agent' );
 141         foreach ( $passThrough as $headerName ) {
 142                 $serverVarName = 'HTTP_' . str_replace( '-', '_', strtoupper( $headerName ) );
 143                 if ( !empty( $_SERVER[$serverVarName] ) ) {
 144                         $headers[] = $headerName . ': ' .
 145                                 str_replace( "\n", '', $_SERVER[$serverVarName] );
 146                 }
 147         }
 148
 149         $ch = curl_init( $reqURL );
 150         if ( $thgThumbCurlConfig['proxy'] ) {
 151                 curl_setopt( $ch, CURLOPT_PROXY, $thgThumbCurlConfig['proxy'] );
 152         }
 153
 154         curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );
 155         curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
 156         curl_setopt( $ch, CURLOPT_TIMEOUT, $thgThumbCurlConfig['timeout'] );
 157
 158         # Actually make the request
 159         $text = curl_exec( $ch );
 160
 161         # Send it on to the client...
 162         $errno = curl_errno( $ch );
 163         $contentType = curl_getinfo( $ch, CURLINFO_CONTENT_TYPE );
 164         $httpCode = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
 165         if ( $errno ) {
 166                 header( 'HTTP/1.1 500 Internal server error' );
 167                 header( 'Cache-Control: no-cache' );
 168                 $contentType = 'text/html';
 169                 $text = wfCurlErrorText( $ch );
 170         } elseif ( $httpCode == 304 ) { // OK
 171                 header( 'HTTP/1.1 304 Not modified' );
 172                 $contentType = '';
 173                 $text = '';
 174         } elseif ( strval( $text ) == '' ) {
 175                 header( 'HTTP/1.1 500 Internal server error' );
 176                 header( 'Cache-Control: no-cache' );
 177                 $contentType = 'text/html';
 178                 $text = wfCurlEmptyText( $ch );
 179         } elseif ( $httpCode == 404 ) {
 180                 header( 'HTTP/1.1 404 Not found' );
 181                 header( 'Cache-Control: s-maxage=300, must-revalidate, max-age=0' );
 182         } elseif ( $httpCode != 200 || substr( $contentType, 0, 9 ) == 'text/html' ) {
 183                 # Error message, suppress cache
 184                 header( 'HTTP/1.1 500 Internal server error' );
 185                 header( 'Cache-Control: no-cache' );
 186         } else {
 187                 # OK thumbnail; save to any backend caches...
 188                 if ( isset( $thgThumbCallbacks['fillCache'] )
 189                         && is_callable( $thgThumbCallbacks['fillCache'] ) )
 190                 {
 191                         call_user_func_array( $thgThumbCallbacks['fillCache'], array( $uri, $text ) );
 192                 }
 193         }
 194
 195         if ( !$contentType ) {
 196                 header( 'Content-Type:' );
 197         } else {
 198                 header( "Content-Type: $contentType" );
 199         }
 200
 201         print $text; // thumb data or error text
 202
 203         curl_close( $ch );
 204 }
 205
 206 /**
 207  * Get error message HTML for when the cURL response is an error.
 208  *
 209  * @param $ch cURL handle
 210  * @return string
 211  */
 212 function wfCurlErrorText( $ch ) {
 213         $error = htmlspecialchars( curl_error( $ch ) );
 214         return <<<EOT
 215 <html>
 216 <head><title>Thumbnail error</title></head>
 217 <body>Error retrieving thumbnail from scaling server: $error</body>
 218 </html>
 219 EOT;
 220 }
 221
 222 /**
 223  * Get error message HTML for when the cURL response is empty.
 224  *
 225  * @param $ch cURL handle
 226  * @return string
 227  */
 228 function wfCurlEmptyText( $ch ) {
 229         return <<<EOT
 230 <html>
 231 <head><title>Thumbnail error</title></head>
 232 <body>Error retrieving thumbnail from scaling server: empty response</body>
 233 </html>
 234 EOT;
 235 }
 236
 237 /**
 238  * Print out a generic 404 error message.
 239  *
 240  * @return void
 241  */
 242 function wfDisplay404Error() {
 243         header( 'HTTP/1.1 404 Not Found' );
 244         header( 'Content-Type: text/html;charset=utf-8' );
 245
 246         $prot = isset( $_SERVER['HTTPS'] ) ? "https://" : "http://";
 247         $serv = strlen( $_SERVER['HTTP_HOST'] ) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'];
 248         $loc = $_SERVER["REQUEST_URI"];
 249
 250         $encUrl = htmlspecialchars( $prot . $serv . $loc );
 251
 252         // Looks like a typical apache2 error
 253         $standard_404 = <<<ENDTEXT
 254 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
 255 <html><head>
 256 <title>404 Not Found</title>
 257 </head><body>
 258 <h1>Not Found</h1>
 259 <p>The requested URL $encUrl was not found on this server.</p>
 260 </body></html>
 261 ENDTEXT;
 262
 263         print $standard_404;
 264 }