filter/tex/texdebug.php

   1 <?PHP // $Id$
   2       // This function fetches math. images from the data directory
   3       // If not, it obtains the corresponding TeX expression from the cache_tex db table
   4       // and uses mimeTeX to create the image file
   5
   6     $nomoodlecookie = true;     // Because it interferes with caching
   7
   8     require_once("../../config.php");
   9
  10     if (empty($CFG->textfilters)) {
  11         error ('Filter not enabled!');
  12     } else {
  13         $filters = explode(',', $CFG->textfilters);
  14         if (array_search('filter/tex', $filters) === FALSE) {
  15             error ('Filter not enabled!');
  16         }
  17     }
  18
  19     $CFG->texfilterdir = "filter/tex";
  20     $CFG->teximagedir = "filter/tex";
  21
  22     $query = urldecode($_SERVER['QUERY_STRING']);
  23     error_reporting(E_ALL);
  24
  25     if ($query) {
  26         $output = $query;
  27         $splitpos = strpos($query,'&')-4;
  28         $texexp = substr($query,4,$splitpos);
  29         $md5 = md5($texexp);
  30         if (strpos($query,'ShowDB') || strpos($query,'DeleteDB')) {
  31             $texcache = get_record("cache_filters","filter","tex", "md5key", $md5);
  32         }
  33         if (strpos($query,'ShowDB')) {
  34             if ($texcache) {
  35                 $output = "DB cache_filters entry for $texexp\n";
  36                 $output .= "id = $texcache->id\n";
  37                 $output .= "filter = $texcache->filter\n";
  38                 $output .= "version = $texcache->version\n";
  39                 $output .= "md5key = $texcache->md5key\n";
  40                 $output .= "rawtext = $texcache->rawtext\n";
  41                 $output .= "timemodified = $texcache->timemodified\n";
  42             } else {
  43                 $output = "DB cache_filters entry for $texexp not found\n";
  44             }
  45         }
  46         if (strpos($query,'DeleteDB')) {
  47             if ($texcache) {
  48                 $output = "Deleting DB cache_filters entry for $texexp\n";
  49                 $result =  delete_records("cache_filters","id",$texcache->id);
  50                 if ($result) {
  51                     $result = 1;
  52                 } else {
  53                     $result = 0;
  54                 }
  55                 $output .= "Number of records deleted = $result\n";
  56             } else {
  57                 $output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
  58             }
  59         }
  60         if (strpos($query,'ShowImage')) {
  61             tex2image($texexp);
  62         } else if (strpos($query,'SlashArguments')) {
  63             slasharguments($texexp);
  64         } else {
  65             outputText($output);
  66         }
  67         exit;
  68     }
  69
  70
  71     function outputText($texexp) {
  72         header("Content-type: text/html");
  73         echo "<html><body><pre>\n";
  74         if ($texexp) {
  75             $texexp = str_replace('<','&lt;',$texexp);
  76             $texexp = str_replace('>','&gt;',$texexp);
  77             $texexp = str_replace('"','&quot;',$texexp);
  78             echo "$texexp\n\n";
  79         } else {
  80             echo "No text output available\n\n";
  81         }
  82         echo "</pre></body></html>\n";
  83     }
  84
  85     function tex2image($texexp, $return=false) {
  86         global $CFG;
  87         $error_message1 = "Your system is not configured to run mimeTeX. ";
  88         $error_message1 .= "You need to download the appropriate<br /> executable ";
  89         $error_message1 .= "from <a href=\"http://moodle.org/download/mimetex/\">";
  90         $error_message1 .= "http://moodle.org/download/mimetex/</a>, or obtain the ";
  91         $error_message1 .= "C source<br /> from <a href=\"http://www.forkosh.com/mimetex.zip\">";
  92         $error_message1 .= "http://www.forkosh.com/mimetex.zip</a>, compile it and ";
  93         $error_message1 .= "put the executable into your<br /> moodle/filter/tex/ directory. ";
  94         $error_message1 .= "You also need to edit your moodle/filter/tex/pix.php file<br />";
  95         $error_message1 .= ' by adding the line<br /><pre>       case "' . PHP_OS . "\":\n";
  96         $error_message1 .= "           \$cmd = \"\\\\\"\$CFG->dirroot/\$CFG->texfilterdir/";
  97         $error_message1 .= 'mimetex.' . strtolower(PHP_OS) . "\\\\\" -e \\\\\"\$pathname\\\\\" \". escapeshellarg(\$texexp);";
  98         $error_message1 .= "</pre>You also need to add this to your texdebug.php file.";
  99
 100         if ($texexp) {
 101             $texexp = '\Large ' . $texexp;
 102             $lifetime = 86400;
 103             $image  = md5($texexp) . ".gif";
 104             $filetype = 'image/gif';
 105             if (!file_exists("$CFG->dataroot/$CFG->teximagedir")) {
 106                 make_upload_directory($CFG->teximagedir);
 107             }
 108             $pathname = "$CFG->dataroot/$CFG->teximagedir/$image";
 109             if (file_exists($pathname)) {
 110                 unlink($pathname);
 111             }
 112             $commandpath = "";
 113             $cmd = "";
 114             $texexp = escapeshellarg($texexp);
 115             switch (PHP_OS) {
 116                 case "Linux":
 117                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.linux";
 118                     $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.linux\" -e \"$pathname\" $texexp";
 119                 break;
 120                 case "WINNT":
 121                 case "WIN32":
 122                 case "Windows":
 123                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.exe";
 124                     $cmd = str_replace(' ','^ ',$commandpath);
 125                     $cmd .= " ++ -e  \"$pathname\" $texexp";
 126                 break;
 127                 case "Darwin":
 128                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin";
 129                     $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin\" -e \"$pathname\" $texexp";
 130                 break;
 131             }
 132             if (!$cmd) {
 133                 if (is_executable("$CFG->dirroot/$CFG->texfilterdir/mimetex")) {   /// Use the custom binary
 134                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex";
 135                     $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex -e $pathname $texexp";
 136                 } else {
 137                     error($error_message1);
 138                 }
 139             }
 140             system($cmd, $status);
 141         }
 142         if ($return) {
 143           return $image;
 144         }
 145         if ($texexp && file_exists($pathname)) {
 146             $lastmodified = filemtime($pathname);
 147             header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
 148             header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
 149             header("Cache-control: max_age = $lifetime"); // a day
 150             header("Pragma: ");
 151             header("Content-disposition: inline; filename=$image");
 152             header("Content-length: ".filesize($pathname));
 153             header("Content-type: $filetype");
 154             readfile("$pathname");
 155         } else {
 156             $ecmd = "$cmd 2>&1";
 157             echo `$ecmd` . "<br />\n";
 158             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 159             if ($status == 4) {
 160                 echo "Status corresponds to illegal instruction<br />\n";
 161             } else if ($status == 11) {
 162                 echo "Status corresponds to bus error<br />\n";
 163             } else if ($status == 22) {
 164                 echo "Status corresponds to abnormal termination<br />\n";
 165             }
 166             if (file_exists($commandpath)) {
 167                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 168                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 169                 if (function_exists("md5_file")) {
 170                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 171                 } else {
 172                     $handle = fopen($commandpath,"rb");
 173                     $contents = fread($handle,16384);
 174                     fclose($handle);
 175                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 176                 }
 177             } else {
 178                 echo "mimetex executable $commandpath not found!<br />";
 179             }
 180             echo "Image not found!";
 181         }
 182     }
 183
 184     function slasharguments($texexp) {
 185         global $CFG;
 186         $admin = $CFG->wwwroot . '/' . $CFG->admin . '/config.php';
 187         $image = tex2image($texexp,true);
 188         echo "<p>If the following image displays correctly, set your ";
 189         echo "<a href=\"$admin\" target=\"_blank\">Administration->Configuration->Variables</a> ";
 190         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 191         echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 192         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 193         echo "It should display correctly as ";
 194         echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 195         echo "<p>If neither equation image displays correctly, please seek ";
 196         echo "further help at moodle.org at the ";
 197         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&username=guest\" target=\"_blank\">";
 198         echo "Mathematics Tools Forum</a></p>";
 199     }
 200
 201 ?>
 202
 203 <html>
 204 <head><title>TeX Filter Debugger</title></head>
 205 <body>
 206   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 207        the text box below. (Click <a href="#help">here for help.</a>)
 208           <form action="texdebug.php" method="get"
 209            target="inlineframe">
 210             <center>
 211              <input type="text" name="tex" size="50"
 212                     value="f(x)=\Bigint_{-\infty}^x~e^{-t^2}dt" />
 213             </center>
 214            <ol>
 215            <li>First click on this button <input type="submit" name="ShowDB" value="Show DB Entry" />
 216                to see the cache_filters database entry for this expression.</li>
 217            <li>If the database entry looks corrupt, click on this button to delete it:
 218                <input type="submit" name="DeleteDB" value="Delete DB Entry" /></li>
 219            <li>Then click on this button <input type="submit" name="ShowImage" value="Show Image" />
 220                to show a graphic image of the algebraic expression.</li>
 221            <li>Finally check your slash arguments setting
 222                <input type="submit" name="SlashArguments" value="Check Slash Arguments" /></li>
 223            </ol>
 224           </form> <br /> <br />
 225        <center>
 226           <iframe name="inlineframe" align="middle" width="80%" height="200">
 227           &lt;p&gt;Something is wrong...&lt;/p&gt;
 228           </iframe>
 229        </center> <br />
 230 <hr />
 231 <a name="help">
 232 <h2>Debugging Help</h2>
 233 </a>
 234 <p>First a brief overview of how the TeX filter works. The TeX filter first
 235 searches the database cache_filters table to see if this TeX expression had been
 236 processed before. If not, it adds a DB entry for that expression.  It then
 237 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 238 tag.  The filter/tex/pix.php script then searches the database to find an
 239 appropriate gif image file for that expression and to create one if it doesn't exist.
 240 Here are a few common things that can go wrong and some suggestions on how
 241 you might try to fix them.</p>
 242 <ol>
 243 <li>Something had gone wrong on a previous occasion when the filter tried to
 244 process this expression. Then the database entry for that expression contains
 245 a bad TeX expression in the rawtext field (usually blank). You can fix this
 246 by clicking on &quot;Delete DB Entry&quot;</li>
 247 <li>The TeX to gif image conversion process does not work. If your server is
 248 running Unix, a likely cause is that the mimetex binary you are using is
 249 incompatible with your operating system. You can try compiling it from the
 250 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 251 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 252 binary at <a href="http://moodle.org/download/mimetex/">
 253 http://moodle.org/download/mimetex/</a>. You may then also need to
 254 edit your moodle/filter/tex/pix.php file to add
 255 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 256 in the switch (PHP_OS) statement. Windows users may have a problem properly
 257 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 258 433152 bytes in size. If not, download a fresh copy from
 259 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 260 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
 261 Another possible problem which may affect
 262 both Unix and Windows servers is that the web server doesn't have execute permission
 263 on the mimetex binary. In that case change permissions accordingly</li>
 264 </ol>
 265 </body>
 266 </html>