filter/tex/texdebug.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * This function fetches math. images from the data directory
  19  * If not, it obtains the corresponding TeX expression from the cache_tex db table
  20  * and uses mimeTeX to create the image file
  21  *
  22  * @package    filter
  23  * @subpackage tex
  24  * @copyright  2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
  25  *             Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
  26  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29     require_once("../../config.php");
  30
  31     if (!filter_is_enabled('tex')) {
  32         print_error('filternotenabled');
  33     }
  34
  35     require_once($CFG->libdir.'/filelib.php');
  36     require_once($CFG->dirroot.'/filter/tex/lib.php');
  37     require_once($CFG->dirroot.'/filter/tex/latex.php');
  38
  39     $action = optional_param('action', '', PARAM_ALPHA);
  40     $texexp = optional_param('tex', '', PARAM_RAW);
  41
  42     require_login();
  43     require_capability('moodle/site:config', context_system::instance(), $USER->id); /// Required cap to run this. MDL-18552
  44     if ($action || $texexp) {
  45         require_sesskey();
  46     }
  47
  48     $output = '';
  49
  50     // look up in cache if required
  51     if ($action=='ShowDB' or $action=='DeleteDB') {
  52         $md5 = md5($texexp);
  53         $texcache = $DB->get_record("cache_filters", array("filter"=>"tex", "md5key"=>$md5));
  54     }
  55
  56     // Action: Show DB Entry
  57     if ($action=='ShowDB') {
  58         if ($texcache) {
  59             $output = "DB cache_filters entry for $texexp\n";
  60             $output .= "id = $texcache->id\n";
  61             $output .= "filter = $texcache->filter\n";
  62             $output .= "version = $texcache->version\n";
  63             $output .= "md5key = $texcache->md5key\n";
  64             $output .= "rawtext = $texcache->rawtext\n";
  65             $output .= "timemodified = $texcache->timemodified\n";
  66         } else {
  67             $output = "DB cache_filters entry for $texexp not found\n";
  68         }
  69     }
  70
  71     // Action: Delete DB Entry
  72     if ($action=='DeleteDB') {
  73         if ($texcache) {
  74             $output = "Deleting DB cache_filters entry for $texexp\n";
  75             $result =  $DB->delete_records("cache_filters", array("id"=>$texcache->id));
  76             if ($result) {
  77                 $result = 1;
  78             } else {
  79                 $result = 0;
  80             }
  81             $output .= "Number of records deleted = $result\n";
  82         } else {
  83             $output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
  84         }
  85     }
  86
  87     // Action: Show Image
  88     if ($action=='ShowImageMimetex') {
  89         tex2image($texexp);
  90     }
  91
  92     // Action: Check Slasharguments
  93     if ($action=='SlashArguments') {
  94         slasharguments($texexp);
  95         exit;
  96     }
  97
  98     // Action: Show Tex command line output
  99     if ($action=='ShowImageTex') {
 100         TexOutput($texexp, true);
 101         exit;
 102     }
 103
 104     // Action: Show Tex command line output
 105     if ($action=='ShowOutputTex') {
 106         if (debugging()) {
 107             TexOutput($texexp);
 108         } else {
 109             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
 110         }
 111         exit;
 112     }
 113
 114     if (!empty($action)) {
 115         outputText($output);
 116     }
 117
 118     // nothing more to do if there was any action
 119     if (!empty($action)) {
 120         exit;
 121     }
 122
 123
 124     function outputText($texexp) {
 125         header("Content-type: text/html; charset=utf-8");
 126         echo "<html><body><pre>\n";
 127         if ($texexp) {
 128             echo s($texexp)."\n\n";
 129         } else {
 130             echo "No text output available\n\n";
 131         }
 132         echo "</pre></body></html>\n";
 133     }
 134
 135     function tex2image($texexp, $return=false) {
 136         global $CFG;
 137
 138         if (!$texexp) {
 139             echo 'No tex expresion specified';
 140             return;
 141         }
 142
 143         $image  = md5($texexp) . ".gif";
 144         $filetype = 'image/gif';
 145         if (!file_exists("$CFG->dataroot/filter/tex")) {
 146             make_upload_directory("filter/tex");
 147         }
 148         $pathname = "$CFG->dataroot/filter/tex/$image";
 149         if (file_exists($pathname)) {
 150             unlink($pathname);
 151         }
 152
 153         $texexp = '\Large '.$texexp;
 154         $commandpath = filter_tex_get_executable(true);
 155         $cmd = filter_tex_get_cmd($pathname, $texexp);
 156         system($cmd, $status);
 157
 158         if ($return) {
 159           return $image;
 160         }
 161
 162         if (file_exists($pathname)) {
 163             send_file($pathname, $image);
 164
 165         } else if (debugging()) {
 166             $ecmd = "$cmd 2>&1";
 167             echo `$ecmd` . "<br />\n";
 168             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 169             if ($status == 4) {
 170                 echo "Status corresponds to illegal instruction<br />\n";
 171             } else if ($status == 11) {
 172                 echo "Status corresponds to bus error<br />\n";
 173             } else if ($status == 22) {
 174                 echo "Status corresponds to abnormal termination<br />\n";
 175             }
 176             if (file_exists($commandpath)) {
 177                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 178                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 179                 if (function_exists("md5_file")) {
 180                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 181                 } else {
 182                     $handle = fopen($commandpath,"rb");
 183                     $contents = fread($handle,16384);
 184                     fclose($handle);
 185                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 186                 }
 187             } else {
 188                 echo "mimetex executable $commandpath not found!<br />";
 189             }
 190             echo "Image not found!";
 191         } else {
 192             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
 193         }
 194     }
 195
 196
 197     // test Tex/Ghostscript output - command execution only
 198     function TexOutput($expression, $graphic=false) {
 199         global $CFG;
 200         $output = '';
 201
 202         $latex = new latex();
 203
 204         // first check if it is likely to work at all
 205         $output .= "<h3>Checking executables</h3>\n";
 206         $executablesexist = true;
 207         $pathlatex = trim(get_config('filter_tex', 'pathlatex'), " '\"");
 208         if (is_file($pathlatex)) {
 209             $output .= "latex executable ($pathlatex) is readable<br />\n";
 210         } else {
 211             $executablesexist = false;
 212             $output .= "<b>Error:</b> latex executable ($pathlatex) is not readable<br />\n";
 213         }
 214         $pathdvips = trim(get_config('filter_tex', 'pathdvips'), " '\"");
 215         if (is_file($pathdvips)) {
 216             $output .= "dvips executable ($pathdvips) is readable<br />\n";
 217         } else {
 218             $executablesexist = false;
 219             $output .= "<b>Error:</b> dvips executable ($pathdvips) is not readable<br />\n";
 220         }
 221         $pathconvert = trim(get_config('filter_tex', 'pathconvert'), " '\"");
 222         if (is_file($pathconvert)) {
 223             $output .= "convert executable ($pathconvert) is readable<br />\n";
 224         } else {
 225             $executablesexist = false;
 226             $output .= "<b>Error:</b> convert executable ($pathconvert) is not readable<br />\n";
 227         }
 228         $pathdvisvgm = trim(get_config('filter_tex', 'pathdvisvgm'), " '\"");
 229         if (is_file($pathdvisvgm)) {
 230             $output .= "dvisvgm executable ($pathdvisvgm) is readable<br />\n";
 231         } else {
 232             $executablesexist = false;
 233             $output .= "<b>Error:</b> dvisvgm executable ($pathdvisvgm) is not readable<br />\n";
 234         }
 235
 236         // knowing that it might work..
 237         $md5 = md5($expression);
 238         $output .= "<p>base filename for expression is '$md5'</p>\n";
 239
 240         // temporary paths
 241         $tex = "$md5.tex"; // Absolute paths won't work with openin_any = p setting.
 242         $dvi = "$latex->temp_dir/$md5.dvi";
 243         $ps = "$latex->temp_dir/$md5.ps";
 244         $convertformat = get_config('filter_tex', 'convertformat');
 245         $img = "$latex->temp_dir/$md5.{$convertformat}";
 246
 247         // Change directory to temp dir so that we can work with relative paths.
 248         chdir($latex->temp_dir);
 249
 250         // put the expression as a file into the temp area
 251         $expression = html_entity_decode($expression);
 252         $output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
 253         $doc = $latex->construct_latex_document($expression);
 254         $fh = fopen($tex, 'w');
 255         fputs($fh, $doc);
 256         fclose($fh);
 257
 258         // step 1: latex command
 259         $pathlatex = escapeshellarg($pathlatex);
 260         $cmd = "$pathlatex --interaction=nonstopmode --halt-on-error $tex";
 261         $output .= execute($cmd);
 262
 263         // step 2: dvips command
 264         $pathdvips = escapeshellarg($pathdvips);
 265         $cmd = "$pathdvips -E $dvi -o $ps";
 266         $output .= execute($cmd);
 267
 268         // Step 3: Set convert or dvisvgm command.
 269         if ($convertformat == 'svg') {
 270             $pathdvisvgm = escapeshellarg($pathdvisvgm);
 271             $cmd = "$pathdvisvgm -E $ps -o $img";
 272         } else {
 273             $pathconvert = escapeshellarg($pathconvert);
 274             $cmd = "$pathconvert -density 240 -trim $ps $img ";
 275         }
 276         $output .= execute($cmd);
 277
 278         if (!$graphic) {
 279             echo $output;
 280         } else if (file_exists($img)) {
 281             send_file($img, "$md5.{$convertformat}");
 282         } else {
 283             echo "Error creating image, see command execution output for more details.";
 284         }
 285     }
 286
 287     function execute($cmd) {
 288         exec($cmd, $result, $code);
 289         $output = "<pre>$ $cmd\n";
 290         $lines = implode("\n", $result);
 291         $output .= "OUTPUT: $lines\n";
 292         $output .= "RETURN CODE: $code\n</pre>\n";
 293         return $output;
 294     }
 295
 296     function slasharguments($texexp) {
 297         global $CFG;
 298         $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 299         $image = tex2image($texexp,true);
 300         echo "<p>If the following image displays correctly, set your ";
 301         echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 302         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 303         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php/$image\" align=\"absmiddle\"></p>\n";
 304         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 305         echo "It should display correctly as ";
 306         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 307         echo "<p>If neither equation image displays correctly, please seek ";
 308         echo "further help at moodle.org at the ";
 309         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 310         echo "Mathematics Tools Forum</a></p>";
 311     }
 312
 313 ?>
 314
 315 <html>
 316 <head><title>TeX Filter Debugger</title></head>
 317 <body>
 318   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 319        the text box below. (Click <a href="#help">here for help.</a>)
 320           <form action="texdebug.php" method="get"
 321            target="inlineframe">
 322             <center>
 323              <input type="text" name="tex" size="50"
 324                     value="f(x)=\int_{-\infty}^x~e^{-t^2}dt" />
 325             </center>
 326            <p>The following tests are available:</p>
 327            <ol>
 328            <li><input type="radio" name="action" value="ShowDB" id="ShowDB" />
 329                <label for="ShowDB">See the cache_filters database entry for this expression (if any).</label></li>
 330            <li><input type="radio" name="action" value="DeleteDB" id="DeleteDB" />
 331                <label for="DeleteDB">Delete the cache_filters database entry for this expression (if any).</label></li>
 332            <li><input type="radio" name="action" value="ShowImageMimetex" id="ShowImageMimetex"  checked="checked" />
 333                <label for="ShowImageMimetex">Show a graphic image of the algebraic expression rendered with mimetex.</label></li>
 334            <li><input type="radio" name="action" value="ShowImageTex" id="ShowImageTex" />
 335                <label for="ShowImageTex">Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</label></li>
 336            <li><input type="radio" name="action" value="ShowOutputTex" id="ShowOutputTex" />
 337                <label for="ShowOutputTex">Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</label></li>
 338            <li><input type="radio" name="action" value="SlashArguments" id="SlashArguments" />
 339                <label for="SlashArguments">Check slasharguments setting.</label></li>
 340            </ol>
 341            <input type="submit" value="Do it!" />
 342            <input type="hidden" name="sesskey" value="<?php echo sesskey(); ?>" />
 343           </form> <br /> <br />
 344        <center>
 345           <iframe name="inlineframe" align="middle" width="80%" height="200">
 346           &lt;p&gt;Something is wrong...&lt;/p&gt;
 347           </iframe>
 348        </center> <br />
 349 <hr />
 350 <a name="help">
 351 <h2>Debugging Help</h2>
 352 </a>
 353 <p>First a brief overview of how the TeX filter works. The TeX filter first
 354 searches the database cache_filters table to see if this TeX expression had been
 355 processed before. If not, it adds a DB entry for that expression.  It then
 356 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 357 tag.  The filter/tex/pix.php script then searches the database to find an
 358 appropriate gif/png/svg image file for that expression and to create one if it doesn't exist.
 359 It will then use either the LaTex/Ghostscript renderer (using external executables
 360 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
 361 renderer produces better results and is tried first.
 362 Here are a few common things that can go wrong and some suggestions on how
 363 you might try to fix them.</p>
 364 <ol>
 365 <li>Something had gone wrong on a previous occasion when the filter tried to
 366 process this expression. Then the database entry for that expression contains
 367 a bad TeX expression in the rawtext field (usually blank). You can fix this
 368 by clicking on &quot;Delete DB Entry&quot;</li>
 369 <li>The TeX to gif/png/svg image conversion process does not work.
 370 If paths are specified in the filter configuation screen for the three
 371 executables these will be tried first. Note that they still must be correctly
 372 installed and have the correct permissions. In particular make sure that you
 373 have all the packages installed (e.g., on Debian/Ubuntu you need to install
 374 the 'tetex-extra' package). Running the 'show command execution' test should
 375 give a big clue.
 376 If this fails or is not available, the Mimetex executable is tried. If this
 377 fails a likely cause is that the mimetex binary you are using is
 378 incompatible with your operating system. You can try compiling it from the
 379 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 380 http://www.forkosh.com/mimetex.zip</a>.
 381 Another possible problem which may affect
 382 both Unix and Windows servers is that the web server doesn't have execute permission
 383 on the mimetex binary. In that case change permissions accordingly</li>
 384 </ol>
 385 </body>
 386 </html>