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     $nomoodlecookie = true;     // Because it interferes with caching
   7
   8     require_once("../../config.php");
   9     require( 'latex.php' );
  10
  11     if (empty($CFG->textfilters)) {
  12         error ('Filter not enabled!');
  13     } else {
  14         $filters = explode(',', $CFG->textfilters);
  15         if (array_search('filter/tex', $filters) === FALSE) {
  16             error ('Filter not enabled!');
  17         }
  18     }
  19
  20     $CFG->texfilterdir = "filter/tex";
  21     $CFG->teximagedir = "filter/tex";
  22
  23     $param = null;
  24     $param->action = optional_param( 'action','',PARAM_ALPHA );
  25     $param->tex = optional_param( 'tex','' );
  26
  27     $query = urldecode($_SERVER['QUERY_STRING']);
  28     error_reporting(E_ALL);
  29     $output = '';
  30
  31     // look up in cache if required
  32     if ($param->action=='ShowDB' or  $param->action=='DeleteDB') {
  33         $md5 = md5($param->tex);
  34         $texcache = get_record("cache_filters","filter","tex", "md5key", $md5);
  35     }
  36
  37     // Action: Show DB Entry
  38     if ($param->action=='ShowDB') {
  39         if ($texcache) {
  40             $output = "DB cache_filters entry for $param->tex\n";
  41             $output .= "id = $texcache->id\n";
  42             $output .= "filter = $texcache->filter\n";
  43             $output .= "version = $texcache->version\n";
  44             $output .= "md5key = $texcache->md5key\n";
  45             $output .= "rawtext = $texcache->rawtext\n";
  46             $output .= "timemodified = $texcache->timemodified\n";
  47         } else {
  48             $output = "DB cache_filters entry for $param->tex not found\n";
  49         }
  50     }
  51
  52     // Action: Delete DB Entry
  53     if ($param->action=='DeleteDB') {
  54         if ($texcache) {
  55             $output = "Deleting DB cache_filters entry for $param->tex\n";
  56             $result =  delete_records("cache_filters","id",$texcache->id);
  57             if ($result) {
  58                 $result = 1;
  59             } else {
  60                 $result = 0;
  61             }
  62             $output .= "Number of records deleted = $result\n";
  63         } else {
  64             $output = "Could not delete DB cache_filters entry for $param->tex\nbecause it could not be found.\n";
  65         }
  66     }
  67
  68     // Action: Show Image
  69     if ($param->action=='ShowImageMimetex') {
  70         tex2image($param->tex);
  71     }
  72
  73     // Action: Check Slasharguments
  74     if ($param->action=='SlashArguments') {
  75         slasharguments($param->tex);
  76     }
  77
  78     // Action: Show Tex command line output
  79     if ($param->action=='ShowImageTex') {
  80         TexOutput($param->tex, true);
  81         exit;
  82     }
  83
  84     // Action: Show Tex command line output
  85     if ($param->action=='ShowOutputTex') {
  86         TexOutput($param->tex);
  87         exit;
  88     }
  89
  90     if (!empty($param->action)) {
  91         outputText($output);
  92     }
  93
  94     // nothing more to do if there was any action
  95     if (!empty($param->action)) {
  96         exit;
  97     }
  98
  99
 100     function outputText($texexp) {
 101         header("Content-type: text/html");
 102         echo "<html><body><pre>\n";
 103         if ($texexp) {
 104             $texexp = str_replace('<','&lt;',$texexp);
 105             $texexp = str_replace('>','&gt;',$texexp);
 106             $texexp = str_replace('"','&quot;',$texexp);
 107             echo "$texexp\n\n";
 108         } else {
 109             echo "No text output available\n\n";
 110         }
 111         echo "</pre></body></html>\n";
 112     }
 113
 114     function tex2image($texexp, $return=false) {
 115         global $CFG;
 116         $error_message1 = "Your system is not configured to run mimeTeX. ";
 117         $error_message1 .= "You need to download the appropriate<br /> executable ";
 118         $error_message1 .= "from <a href=\"http://moodle.org/download/mimetex/\">";
 119         $error_message1 .= "http://moodle.org/download/mimetex/</a>, or obtain the ";
 120         $error_message1 .= "C source<br /> from <a href=\"http://www.forkosh.com/mimetex.zip\">";
 121         $error_message1 .= "http://www.forkosh.com/mimetex.zip</a>, compile it and ";
 122         $error_message1 .= "put the executable into your<br /> moodle/filter/tex/ directory. ";
 123         $error_message1 .= "You also need to edit your moodle/filter/tex/pix.php file<br />";
 124         $error_message1 .= ' by adding the line<br /><pre>       case "' . PHP_OS . "\":\n";
 125         $error_message1 .= "           \$cmd = \"\\\\\"\$CFG->dirroot/\$CFG->texfilterdir/";
 126         $error_message1 .= 'mimetex.' . strtolower(PHP_OS) . "\\\\\" -e \\\\\"\$pathname\\\\\" \". escapeshellarg(\$texexp);";
 127         $error_message1 .= "</pre>You also need to add this to your texdebug.php file.";
 128
 129         if ($texexp) {
 130             $texexp = '\Large ' . $texexp;
 131             $lifetime = 86400;
 132             $image  = md5($texexp) . ".gif";
 133             $filetype = 'image/gif';
 134             if (!file_exists("$CFG->dataroot/$CFG->teximagedir")) {
 135                 make_upload_directory($CFG->teximagedir);
 136             }
 137             $pathname = "$CFG->dataroot/$CFG->teximagedir/$image";
 138             if (file_exists($pathname)) {
 139                 unlink($pathname);
 140             }
 141             $commandpath = "";
 142             $cmd = "";
 143             $texexp = escapeshellarg($texexp);
 144             switch (PHP_OS) {
 145                 case "Linux":
 146                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.linux";
 147                     $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.linux\" -e \"$pathname\" $texexp";
 148                 break;
 149                 case "WINNT":
 150                 case "WIN32":
 151                 case "Windows":
 152                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.exe";
 153                     $cmd = str_replace(' ','^ ',$commandpath);
 154                     $cmd .= " ++ -e  \"$pathname\" $texexp";
 155                 break;
 156                 case "Darwin":
 157                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin";
 158                     $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin\" -e \"$pathname\" $texexp";
 159                 break;
 160             }
 161             if (!$cmd) {
 162                 if (is_executable("$CFG->dirroot/$CFG->texfilterdir/mimetex")) {   /// Use the custom binary
 163                     $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex";
 164                     $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex -e $pathname $texexp";
 165                 } else {
 166                     error($error_message1);
 167                 }
 168             }
 169             system($cmd, $status);
 170         }
 171         if ($return) {
 172           return $image;
 173         }
 174         if ($texexp && file_exists($pathname)) {
 175             $lastmodified = filemtime($pathname);
 176             header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
 177             header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
 178             header("Cache-control: max_age = $lifetime"); // a day
 179             header("Pragma: ");
 180             header("Content-disposition: inline; filename=$image");
 181             header("Content-length: ".filesize($pathname));
 182             header("Content-type: $filetype");
 183             readfile("$pathname");
 184         } else {
 185             $ecmd = "$cmd 2>&1";
 186             echo `$ecmd` . "<br />\n";
 187             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 188             if ($status == 4) {
 189                 echo "Status corresponds to illegal instruction<br />\n";
 190             } else if ($status == 11) {
 191                 echo "Status corresponds to bus error<br />\n";
 192             } else if ($status == 22) {
 193                 echo "Status corresponds to abnormal termination<br />\n";
 194             }
 195             if (file_exists($commandpath)) {
 196                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 197                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 198                 if (function_exists("md5_file")) {
 199                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 200                 } else {
 201                     $handle = fopen($commandpath,"rb");
 202                     $contents = fread($handle,16384);
 203                     fclose($handle);
 204                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 205                 }
 206             } else {
 207                 echo "mimetex executable $commandpath not found!<br />";
 208             }
 209             echo "Image not found!";
 210         }
 211     }
 212
 213
 214     // test Tex/Ghostscript output - command execution only
 215     function TexOutput( $expression, $graphic=false ) {
 216         global $CFG;
 217         $output = '';
 218
 219         $latex = new latex();
 220
 221         // first check if it is likely to work at all
 222         $output .= "<h3>Checking executables</h3>\n";
 223         $executables_exist = true;
 224         if (is_file($CFG->filter_tex_pathlatex)) {
 225             $output .= "latex executable ($CFG->filter_tex_pathlatex) is readable<br />\n";
 226         }
 227         else {
 228             $executables_exist = false;
 229             $output .= "<b>Error:</b> latex executable ($CFG->filter_tex_pathlatex) is not readable<br />\n";
 230         }
 231         if (is_file($CFG->filter_tex_pathdvips)) {
 232             $output .= "dvips executable ($CFG->filter_tex_pathdvips) is readable<br />\n";
 233         }
 234         else {
 235             $executables_exist = false;
 236             $output .= "<b>Error:</b> dvips executable ($CFG->filter_tex_pathdvips) is not readable<br />\n";
 237         }
 238         if (is_file($CFG->filter_tex_pathconvert)) {
 239             $output .= "convert executable ($CFG->filter_tex_pathconvert) is readable<br />\n";
 240         }
 241         else {
 242             $executables_exist = false;
 243             $output .= "<b>Error:</b> convert executable ($CFG->filter_tex_pathconvert) is not readable<br />\n";
 244         }
 245
 246         // knowing that it might work..
 247         $md5 = md5( $expression );
 248         $output .= "<p>base filename for expression is '$md5'</p>\n";
 249
 250         // temporary paths
 251         $tex = "$latex->temp_dir/$md5.tex";
 252         $dvi = "$latex->temp_dir/$md5.dvi";
 253         $ps = "$latex->temp_dir/$md5.ps";
 254         $gif = "$latex->temp_dir/$md5.gif";
 255
 256         // put the expression as a file into the temp area
 257         $expression = html_entity_decode( $expression );
 258         $output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
 259         $doc = $latex->construct_latex_document( $expression );
 260         $fh = fopen( $tex, 'w' );
 261         fputs( $fh, $doc );
 262         fclose( $fh );
 263
 264         // cd to temp dir
 265         chdir( $latex->temp_dir );
 266
 267         // step 1: latex command
 268         $cmd = "$CFG->filter_tex_pathlatex --interaction=nonstopmode $tex";
 269         $output .= execute( $cmd );
 270
 271         // step 2: dvips command
 272         $cmd = "$CFG->filter_tex_pathdvips -E $dvi -o $ps";
 273         $output .= execute( $cmd );
 274
 275         // step 3: convert command
 276         $cmd = "$CFG->filter_tex_pathconvert -density 240 -trim $ps $gif ";
 277         $output .= execute( $cmd );
 278
 279         if (!$graphic) {
 280             echo( $output );
 281         } else {
 282             $lastmodified = filemtime($gif);
 283             $lifetime = 86400;
 284             $filetype = 'image/gif';
 285             $image = "$md5.gif";
 286             header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
 287             header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
 288             header("Cache-control: max_age = $lifetime"); // a day
 289             header("Pragma: ");
 290             header("Content-disposition: inline; filename=$image");
 291             header("Content-length: ".filesize($gif));
 292             header("Content-type: $filetype");
 293             readfile("$gif");
 294          }
 295     }
 296
 297     function execute( $cmd ) {
 298         exec( $cmd, $result, $code );
 299         $output = "<pre>$ $cmd\n";
 300         $lines = implode( "\n", $result );
 301         $output .= "OUTPUT: $lines\n";
 302         $output .= "RETURN CODE: $code\n</pre>\n";
 303         return $output;
 304     }
 305
 306     function slasharguments($texexp) {
 307         global $CFG;
 308         $admin = $CFG->wwwroot . '/' . $CFG->admin . '/config.php';
 309         $image = tex2image($texexp,true);
 310         echo "<p>If the following image displays correctly, set your ";
 311         echo "<a href=\"$admin\" target=\"_blank\">Administration->Configuration->Variables</a> ";
 312         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 313         echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 314         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 315         echo "It should display correctly as ";
 316         echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 317         echo "<p>If neither equation image displays correctly, please seek ";
 318         echo "further help at moodle.org at the ";
 319         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&username=guest\" target=\"_blank\">";
 320         echo "Mathematics Tools Forum</a></p>";
 321     }
 322
 323 ?>
 324
 325 <html>
 326 <head><title>TeX Filter Debugger</title></head>
 327 <body>
 328   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 329        the text box below. (Click <a href="#help">here for help.</a>)
 330           <form action="texdebug.php" method="get"
 331            target="inlineframe">
 332             <center>
 333              <input type="text" name="tex" size="50"
 334                     value="f(x)=\Bigint_{-\infty}^x~e^{-t^2}dt" />
 335             </center>
 336            <p>The following tests are available:</p>
 337            <ol>
 338            <li><input type="radio" name="action" value="ShowDB" />
 339                See the cache_filters database entry for this expression (if any).</li>
 340            <li><input type="radio" name="DeleteDB" value="DeleteDB" />
 341                Delete the cache_filters database entry for this expression (if any).</li>
 342            <li><input type="radio" name="action" value="ShowImageMimetex" />
 343                Show a graphic image of the algebraic expression rendered with mimetex.</li>
 344            <li><input type="radio" name="action" value="ShowImageTex" />
 345                Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</li>
 346            <li><input type="radio" name="action" value="ShowOutputTex" />
 347                Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</li>
 348            <li><input type="radio" name="action" value="SlashArguments" />
 349                Check slasharguments setting.</li>
 350            </ol>
 351            <input type="submit" value="Do it!" />
 352           </form> <br /> <br />
 353        <center>
 354           <iframe name="inlineframe" align="middle" width="80%" height="200">
 355           &lt;p&gt;Something is wrong...&lt;/p&gt;
 356           </iframe>
 357        </center> <br />
 358 <hr />
 359 <a name="help">
 360 <h2>Debugging Help</h2>
 361 </a>
 362 <p>First a brief overview of how the TeX filter works. The TeX filter first
 363 searches the database cache_filters table to see if this TeX expression had been
 364 processed before. If not, it adds a DB entry for that expression.  It then
 365 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 366 tag.  The filter/tex/pix.php script then searches the database to find an
 367 appropriate gif image file for that expression and to create one if it doesn't exist.
 368 It will then use either the LaTex/Ghostscript renderer (using external executables
 369 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
 370 renderer produces better results and is tried first.
 371 Here are a few common things that can go wrong and some suggestions on how
 372 you might try to fix them.</p>
 373 <ol>
 374 <li>Something had gone wrong on a previous occasion when the filter tried to
 375 process this expression. Then the database entry for that expression contains
 376 a bad TeX expression in the rawtext field (usually blank). You can fix this
 377 by clicking on &quot;Delete DB Entry&quot;</li>
 378 <li>The TeX to gif image conversion process does not work.
 379 If paths are specified in the filter configuation screen for the three
 380 executables these will be tried first. Note that they still must be correctly
 381 installed and have the correct permissions. In particular make sure that you
 382 have all the packages installed (e.g., on Debian/Ubuntu you need to install
 383 the 'tetex-extra' package). Running the 'show command execution' test should
 384 give a big clue.
 385 If this fails or is not available, the Mimetex executable is tried. If this
 386 fails a likely cause is that the mimetex binary you are using is
 387 incompatible with your operating system. You can try compiling it from the
 388 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 389 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 390 binary at <a href="http://moodle.org/download/mimetex/">
 391 http://moodle.org/download/mimetex/</a>. You may then also need to
 392 edit your moodle/filter/tex/pix.php file to add
 393 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 394 in the switch (PHP_OS) statement. Windows users may have a problem properly
 395 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 396 433152 bytes in size. If not, download a fresh copy from
 397 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 398 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
 399 Another possible problem which may affect
 400 both Unix and Windows servers is that the web server doesn't have execute permission
 401 on the mimetex binary. In that case change permissions accordingly</li>
 402 </ol>
 403 </body>
 404 </html>