thumb_handler.php

   1 <?php
   2
   3 # Valid web server entry point
   4 define( 'THUMB_HANDLER', true );
   5
   6 # Load thumb-handler configuration. We don't want to use
   7 # WebStart.php or the like as it would kill performance.
   8 $configPath = dirname( __FILE__ ) . "/thumb.config.php";
   9 if ( !file_exists( $configPath ) ) {
  10         die( "Thumb-handler.php is not enabled for this wiki.\n" );
  11 } elseif ( !extension_loaded( 'curl' ) ) {
  12         die( "cURL is not enabled for PHP on this wiki.\n" ); // sanity
  13 }
  14 require( $configPath );
  15
  16 wfHandleThumb404Main();
  17
  18 function wfHandleThumb404Main() {
  19         global $thgThumbCallbacks, $thgThumb404File;
  20
  21         # lighttpd puts the original request in REQUEST_URI, while
  22         # sjs sets that to the 404 handler, and puts the original
  23         # request in REDIRECT_URL.
  24         if ( isset( $_SERVER['REDIRECT_URL'] ) ) {
  25                 # The URL is un-encoded, so put it back how it was.
  26                 $uri = str_replace( "%2F", "/", urlencode( $_SERVER['REDIRECT_URL'] ) );
  27         } else {
  28                 $uri = $_SERVER['REQUEST_URI'];
  29         }
  30
  31         # Extract thumb.php params from the URI...
  32         if ( isset( $thgThumbCallbacks['extractParams'] )
  33                 && is_callable( $thgThumbCallbacks['extractParams'] ) ) // overridden by configuration?
  34         {
  35                 $params = call_user_func_array( $thgThumbCallbacks['extractParams'], array( $uri ) );
  36         } else {
  37                 $params = wfExtractThumbParams( $uri ); // basic wiki URL param extracting
  38         }
  39
  40         # Show 404 error if this is not a valid thumb request...
  41         if ( !is_array( $params ) ) {
  42                 header( 'X-Debug: no regex match' ); // useful for debugging
  43                 if ( $thgThumb404File ) { // overridden by configuration?
  44                         require( $thgThumb404File );
  45                 } else {
  46                         wfDisplay404Error(); // standard 404 message
  47                 }
  48                 return;
  49         }
  50
  51         # Check any backend caches for the thumbnail...
  52         if ( isset( $thgThumbCallbacks['checkCache'] )
  53                 && is_callable( $thgThumbCallbacks['checkCache'] ) )
  54         {
  55                 if ( call_user_func_array( $thgThumbCallbacks['checkCache'], array( $uri, $params ) ) ) {
  56                         return; // file streamed from backend thumb cache
  57                 }
  58         }
  59
  60         wfStreamThumbViaCurl( $params, $uri );
  61 }
  62
  63 /**
  64  * Extract the required params for thumb.php from the thumbnail request URI.
  65  * At least 'width' and 'f' should be set if the result is an array.
  66  *
  67  * @param $uri String Thumbnail request URI
  68  * @return Array|null associative params array or null
  69  */
  70 function wfExtractThumbParams( $uri ) {
  71         global $thgThumbServer, $thgThumbFragment, $thgThumbHashFragment;
  72
  73         $thumbRegex = '!^(?:' . preg_quote( $thgThumbServer ) . ')?/' .
  74                 preg_quote( $thgThumbFragment ) . '(/archive|/temp|)/' .
  75                 $thgThumbHashFragment . '([^/]*)/(page(\d*)-)*(\d*)px-[^/]*$!';
  76
  77         if ( preg_match( $thumbRegex, $uri, $matches ) ) {
  78                 list( $all, $archOrTemp, $filename, $pagefull, $pagenum, $size ) = $matches;
  79                 $params = array( 'f' => $filename, 'width' => $size );
  80                 if ( $pagenum ) {
  81                         $params['page'] = $pagenum;
  82                 }
  83                 if ( $archOrTemp == '/archive' ) {
  84                         $params['archived'] = 1;
  85                 } elseif ( $archOrTemp == '/temp' ) {
  86                         $params['temp'] = 1;
  87                 }
  88         } else {
  89                 $params = null; // not a valid thumbnail URL
  90         }
  91
  92         return $params;
  93 }
  94
  95 /**
  96  * cURL to thumb.php and stream back the resulting file or give an error message.
  97  *
  98  * @param $params Array Parameters to thumb.php
  99  * @param $uri String Thumbnail request URI
 100  * @return void
 101  */
 102 function wfStreamThumbViaCurl( array $params, $uri ) {
 103         global $thgThumbCallbacks, $thgThumbScriptPath, $thgThumbCurlProxy, $thgThumbCurlTimeout;
 104
 105         # Build up the request URL to use with CURL...
 106         $reqURL = "{$thgThumbScriptPath}?";
 107         $first = true;
 108         foreach ( $params as $name => $value ) {
 109                 if ( $first ) {
 110                         $first = false;
 111                 } else {
 112                         $reqURL .= '&';
 113                 }
 114                 $reqURL .= "$name=$value"; // Note: value is already urlencoded
 115         }
 116
 117         # Set relevant HTTP headers...
 118         $headers = array();
 119         $headers[] = "X-Original-URI: " . str_replace( "\n", '', $uri );
 120         if ( isset( $thgThumbCallbacks['curlHeaders'] )
 121                 && is_callable( $thgThumbCallbacks['curlHeaders'] ) )
 122         {
 123                 # Add on any custom headers (like XFF)
 124                 call_user_func_array( $thgThumbCallbacks['curlHeaders'], array( &$headers ) );
 125         }
 126
 127         # Pass through some other headers...
 128         $passThrough = array( 'If-Modified-Since', 'Referer', 'User-Agent' );
 129         foreach ( $passThrough as $headerName ) {
 130                 $serverVarName = 'HTTP_' . str_replace( '-', '_', strtoupper( $headerName ) );
 131                 if ( !empty( $_SERVER[$serverVarName] ) ) {
 132                         $headers[] = $headerName . ': ' .
 133                                 str_replace( "\n", '', $_SERVER[$serverVarName] );
 134                 }
 135         }
 136
 137         $ch = curl_init( $reqURL );
 138         if ( $thgThumbCurlProxy ) {
 139                 curl_setopt( $ch, CURLOPT_PROXY, $thgThumbCurlProxy );
 140         }
 141
 142         curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );
 143         curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
 144         curl_setopt( $ch, CURLOPT_TIMEOUT, $thgThumbCurlTimeout );
 145
 146         # Actually make the request
 147         $text = curl_exec( $ch );
 148
 149         # Send it on to the client...
 150         $errno = curl_errno( $ch );
 151         $contentType = curl_getinfo( $ch, CURLINFO_CONTENT_TYPE );
 152         $httpCode = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
 153         if ( $errno ) {
 154                 header( 'HTTP/1.1 500 Internal server error' );
 155                 header( 'Cache-Control: no-cache' );
 156                 $contentType = 'text/html';
 157                 $text = wfCurlErrorText( $ch );
 158         } elseif ( $httpCode == 304 ) { // OK
 159                 header( 'HTTP/1.1 304 Not modified' );
 160                 $contentType = '';
 161                 $text = '';
 162         } elseif ( strval( $text ) == '' ) {
 163                 header( 'HTTP/1.1 500 Internal server error' );
 164                 header( 'Cache-Control: no-cache' );
 165                 $contentType = 'text/html';
 166                 $text = wfCurlEmptyText( $ch );
 167         } elseif ( $httpCode == 404 ) {
 168                 header( 'HTTP/1.1 404 Not found' );
 169                 header( 'Cache-Control: s-maxage=300, must-revalidate, max-age=0' );
 170         } elseif ( $httpCode != 200 || substr( $contentType, 0, 9 ) == 'text/html' ) {
 171                 # Error message, suppress cache
 172                 header( 'HTTP/1.1 500 Internal server error' );
 173                 header( 'Cache-Control: no-cache' );
 174         } else {
 175                 # OK thumbnail; save to any backend caches...
 176                 if ( isset( $thgThumbCallbacks['fillCache'] )
 177                         && is_callable( $thgThumbCallbacks['fillCache'] ) )
 178                 {
 179                         call_user_func_array( $thgThumbCallbacks['fillCache'], array( $uri, $text ) );
 180                 }
 181         }
 182
 183         if ( !$contentType ) {
 184                 header( 'Content-Type:' );
 185         } else {
 186                 header( "Content-Type: $contentType" );
 187         }
 188
 189         print $text; // thumb data or error text
 190
 191         curl_close( $ch );
 192 }
 193
 194 /**
 195  * Get error message HTML for when the cURL response is an error.
 196  *
 197  * @param $ch cURL handle
 198  * @return string
 199  */
 200 function wfCurlErrorText( $ch ) {
 201         $error = htmlspecialchars( curl_error( $ch ) );
 202         return <<<EOT
 203 <html>
 204 <head><title>Thumbnail error</title></head>
 205 <body>Error retrieving thumbnail from scaling server: $error</body>
 206 </html>
 207 EOT;
 208 }
 209
 210 /**
 211  * Get error message HTML for when the cURL response is empty.
 212  *
 213  * @param $ch cURL handle
 214  * @return string
 215  */
 216 function wfCurlEmptyText( $ch ) {
 217         return <<<EOT
 218 <html>
 219 <head><title>Thumbnail error</title></head>
 220 <body>Error retrieving thumbnail from scaling server: empty response</body>
 221 </html>
 222 EOT;
 223 }
 224
 225 /**
 226  * Print out a generic 404 error message.
 227  *
 228  * @return void
 229  */
 230 function wfDisplay404Error() {
 231         header( 'HTTP/1.1 404 Not Found' );
 232         header( 'Content-Type: text/html;charset=utf-8' );
 233
 234         $prot = isset( $_SERVER['HTTPS'] ) ? "https://" : "http://";
 235         $serv = strlen( $_SERVER['HTTP_HOST'] ) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'];
 236         $loc = $_SERVER["REQUEST_URI"];
 237
 238         $encUrl = htmlspecialchars( $prot . $serv . $loc );
 239
 240         // Looks like a typical apache2 error
 241         $standard_404 = <<<ENDTEXT
 242 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
 243 <html><head>
 244 <title>404 Not Found</title>
 245 </head><body>
 246 <h1>Not Found</h1>
 247 <p>The requested URL $encUrl was not found on this server.</p>
 248 </body></html>
 249 ENDTEXT;
 250
 251         print $standard_404;
 252 }