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         $doc = $latex->construct_latex_document( $expression );
 258         $fh = fopen( $tex, 'w' );
 259         fputs( $fh, $doc );
 260         fclose( $fh );
 261
 262         // cd to temp dir
 263         chdir( $latex->temp_dir );
 264
 265         // step 1: latex command
 266         $cmd = "$CFG->filter_tex_pathlatex --interaction=nonstopmode $tex";
 267         $output .= execute( $cmd );
 268
 269         // step 2: dvips command
 270         $cmd = "$CFG->filter_tex_pathdvips -E $dvi -o $ps";
 271         $output .= execute( $cmd );
 272
 273         // step 3: convert command
 274         $cmd = "$CFG->filter_tex_pathconvert -density 240 -trim $ps $gif ";
 275         $output .= execute( $cmd );
 276
 277         if (!$graphic) {
 278             echo( $output );
 279         } else {
 280             $lastmodified = filemtime($gif);
 281             $lifetime = 86400;
 282             $filetype = 'image/gif';
 283             $image = "$md5.gif";
 284             header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
 285             header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
 286             header("Cache-control: max_age = $lifetime"); // a day
 287             header("Pragma: ");
 288             header("Content-disposition: inline; filename=$image");
 289             header("Content-length: ".filesize($gif));
 290             header("Content-type: $filetype");
 291             readfile("$gif");
 292          }
 293     }
 294
 295     function execute( $cmd ) {
 296         exec( $cmd, $result, $code );
 297         $output = "<pre>$ $cmd\n";
 298         $lines = implode( "\n", $result );
 299         $output .= "OUTPUT: $lines\n";
 300         $output .= "RETURN CODE: $code\n</pre>\n";
 301         return $output;
 302     }
 303
 304     function slasharguments($texexp) {
 305         global $CFG;
 306         $admin = $CFG->wwwroot . '/' . $CFG->admin . '/config.php';
 307         $image = tex2image($texexp,true);
 308         echo "<p>If the following image displays correctly, set your ";
 309         echo "<a href=\"$admin\" target=\"_blank\">Administration->Configuration->Variables</a> ";
 310         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 311         echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 312         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 313         echo "It should display correctly as ";
 314         echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 315         echo "<p>If neither equation image displays correctly, please seek ";
 316         echo "further help at moodle.org at the ";
 317         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&username=guest\" target=\"_blank\">";
 318         echo "Mathematics Tools Forum</a></p>";
 319     }
 320
 321 ?>
 322
 323 <html>
 324 <head><title>TeX Filter Debugger</title></head>
 325 <body>
 326   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 327        the text box below. (Click <a href="#help">here for help.</a>)
 328           <form action="texdebug.php" method="get"
 329            target="inlineframe">
 330             <center>
 331              <input type="text" name="tex" size="50"
 332                     value="f(x)=\Bigint_{-\infty}^x~e^{-t^2}dt" />
 333             </center>
 334            <p>The following tests are available:</p>
 335            <ol>
 336            <li><input type="radio" name="action" value="ShowDB" />
 337                See the cache_filters database entry for this expression (if any).</li>
 338            <li><input type="radio" name="DeleteDB" value="DeleteDB" />
 339                Delete the cache_filters database entry for this expression (if any).</li>
 340            <li><input type="radio" name="action" value="ShowImageMimetex" />
 341                Show a graphic image of the algebraic expression rendered with mimetex.</li>
 342            <li><input type="radio" name="action" value="ShowImageTex" />
 343                Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</li>
 344            <li><input type="radio" name="action" value="ShowOutputTex" />
 345                Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</li>
 346            <li><input type="radio" name="action" value="SlashArguments" />
 347                Check slasharguments setting.</li>
 348            </ol>
 349            <input type="submit" value="Do it!" />
 350           </form> <br /> <br />
 351        <center>
 352           <iframe name="inlineframe" align="middle" width="80%" height="200">
 353           &lt;p&gt;Something is wrong...&lt;/p&gt;
 354           </iframe>
 355        </center> <br />
 356 <hr />
 357 <a name="help">
 358 <h2>Debugging Help</h2>
 359 </a>
 360 <p>First a brief overview of how the TeX filter works. The TeX filter first
 361 searches the database cache_filters table to see if this TeX expression had been
 362 processed before. If not, it adds a DB entry for that expression.  It then
 363 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 364 tag.  The filter/tex/pix.php script then searches the database to find an
 365 appropriate gif image file for that expression and to create one if it doesn't exist.
 366 It will then use either the LaTex/Ghostscript renderer (using external executables
 367 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
 368 renderer produces better results and is tried first.
 369 Here are a few common things that can go wrong and some suggestions on how
 370 you might try to fix them.</p>
 371 <ol>
 372 <li>Something had gone wrong on a previous occasion when the filter tried to
 373 process this expression. Then the database entry for that expression contains
 374 a bad TeX expression in the rawtext field (usually blank). You can fix this
 375 by clicking on &quot;Delete DB Entry&quot;</li>
 376 <li>The TeX to gif image conversion process does not work.
 377 If paths are specified in the filter configuation screen for the three
 378 executables these will be tried first. Note that they still must be correctly
 379 installed and have the correct permissions. In particular make sure that you
 380 have all the packages installed (e.g., on Debian/Ubuntu you need to install
 381 the 'tetex-extra' package). Running the 'show command execution' test should
 382 give a big clue.
 383 If this fails or is not available, the Mimetex executable is tried. If this
 384 fails a likely cause is that the mimetex binary you are using is
 385 incompatible with your operating system. You can try compiling it from the
 386 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 387 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 388 binary at <a href="http://moodle.org/download/mimetex/">
 389 http://moodle.org/download/mimetex/</a>. You may then also need to
 390 edit your moodle/filter/tex/pix.php file to add
 391 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 392 in the switch (PHP_OS) statement. Windows users may have a problem properly
 393 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 394 433152 bytes in size. If not, download a fresh copy from
 395 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 396 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
 397 Another possible problem which may affect
 398 both Unix and Windows servers is that the web server doesn't have execute permission
 399 on the mimetex binary. In that case change permissions accordingly</li>
 400 </ol>
 401 </body>
 402 </html>