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('filter/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', get_context_instance(CONTEXT_SYSTEM), $USER->id); /// Required cap to run this. MDL-18552
  44
  45     $output = '';
  46
  47     // look up in cache if required
  48     if ($action=='ShowDB' or $action=='DeleteDB') {
  49         $md5 = md5($texexp);
  50         $texcache = $DB->get_record("cache_filters", array("filter"=>"tex", "md5key"=>$md5));
  51     }
  52
  53     // Action: Show DB Entry
  54     if ($action=='ShowDB') {
  55         if ($texcache) {
  56             $output = "DB cache_filters entry for $texexp\n";
  57             $output .= "id = $texcache->id\n";
  58             $output .= "filter = $texcache->filter\n";
  59             $output .= "version = $texcache->version\n";
  60             $output .= "md5key = $texcache->md5key\n";
  61             $output .= "rawtext = $texcache->rawtext\n";
  62             $output .= "timemodified = $texcache->timemodified\n";
  63         } else {
  64             $output = "DB cache_filters entry for $texexp not found\n";
  65         }
  66     }
  67
  68     // Action: Delete DB Entry
  69     if ($action=='DeleteDB') {
  70         if ($texcache) {
  71             $output = "Deleting DB cache_filters entry for $texexp\n";
  72             $result =  $DB->delete_records("cache_filters", array("id"=>$texcache->id));
  73             if ($result) {
  74                 $result = 1;
  75             } else {
  76                 $result = 0;
  77             }
  78             $output .= "Number of records deleted = $result\n";
  79         } else {
  80             $output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
  81         }
  82     }
  83
  84     // Action: Show Image
  85     if ($action=='ShowImageMimetex') {
  86         tex2image($texexp);
  87     }
  88
  89     // Action: Check Slasharguments
  90     if ($action=='SlashArguments') {
  91         slasharguments($texexp);
  92     }
  93
  94     // Action: Show Tex command line output
  95     if ($action=='ShowImageTex') {
  96         TexOutput($texexp, true);
  97         exit;
  98     }
  99
 100     // Action: Show Tex command line output
 101     if ($action=='ShowOutputTex') {
 102         if (debugging()) {
 103             TexOutput($texexp);
 104         } else {
 105             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
 106         }
 107         exit;
 108     }
 109
 110     if (!empty($action)) {
 111         outputText($output);
 112     }
 113
 114     // nothing more to do if there was any action
 115     if (!empty($action)) {
 116         exit;
 117     }
 118
 119
 120     function outputText($texexp) {
 121         header("Content-type: text/html; charset=utf-8");
 122         echo "<html><body><pre>\n";
 123         if ($texexp) {
 124             echo s($texexp)."\n\n";
 125         } else {
 126             echo "No text output available\n\n";
 127         }
 128         echo "</pre></body></html>\n";
 129     }
 130
 131     function tex2image($texexp, $return=false) {
 132         global $CFG;
 133
 134         if (!$texexp) {
 135             echo 'No tex expresion specified';
 136             return;
 137         }
 138
 139         $image  = md5($texexp) . ".gif";
 140         $filetype = 'image/gif';
 141         if (!file_exists("$CFG->dataroot/filter/tex")) {
 142             make_upload_directory("filter/tex");
 143         }
 144         $pathname = "$CFG->dataroot/filter/tex/$image";
 145         if (file_exists($pathname)) {
 146             unlink($pathname);
 147         }
 148
 149         $texexp = '\Large '.$texexp;
 150         $commandpath = filter_tex_get_executable(true);
 151         $cmd = filter_tex_get_cmd($pathname, $texexp);
 152         system($cmd, $status);
 153
 154         if ($return) {
 155           return $image;
 156         }
 157
 158         if (file_exists($pathname)) {
 159             send_file($pathname, $image);
 160
 161         } else if (debugging()) {
 162             $ecmd = "$cmd 2>&1";
 163             echo `$ecmd` . "<br />\n";
 164             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 165             if ($status == 4) {
 166                 echo "Status corresponds to illegal instruction<br />\n";
 167             } else if ($status == 11) {
 168                 echo "Status corresponds to bus error<br />\n";
 169             } else if ($status == 22) {
 170                 echo "Status corresponds to abnormal termination<br />\n";
 171             }
 172             if (file_exists($commandpath)) {
 173                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 174                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 175                 if (function_exists("md5_file")) {
 176                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 177                 } else {
 178                     $handle = fopen($commandpath,"rb");
 179                     $contents = fread($handle,16384);
 180                     fclose($handle);
 181                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 182                 }
 183             } else {
 184                 echo "mimetex executable $commandpath not found!<br />";
 185             }
 186             echo "Image not found!";
 187         } else {
 188             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
 189         }
 190     }
 191
 192
 193     // test Tex/Ghostscript output - command execution only
 194     function TexOutput($expression, $graphic=false) {
 195         global $CFG;
 196         $output = '';
 197
 198         $latex = new latex();
 199
 200         // first check if it is likely to work at all
 201         $output .= "<h3>Checking executables</h3>\n";
 202         $executables_exist = true;
 203         if (is_file($CFG->filter_tex_pathlatex)) {
 204             $output .= "latex executable ($CFG->filter_tex_pathlatex) is readable<br />\n";
 205         }
 206         else {
 207             $executables_exist = false;
 208             $output .= "<b>Error:</b> latex executable ($CFG->filter_tex_pathlatex) is not readable<br />\n";
 209         }
 210         if (is_file($CFG->filter_tex_pathdvips)) {
 211             $output .= "dvips executable ($CFG->filter_tex_pathdvips) is readable<br />\n";
 212         }
 213         else {
 214             $executables_exist = false;
 215             $output .= "<b>Error:</b> dvips executable ($CFG->filter_tex_pathdvips) is not readable<br />\n";
 216         }
 217         if (is_file($CFG->filter_tex_pathconvert)) {
 218             $output .= "convert executable ($CFG->filter_tex_pathconvert) is readable<br />\n";
 219         }
 220         else {
 221             $executables_exist = false;
 222             $output .= "<b>Error:</b> convert executable ($CFG->filter_tex_pathconvert) is not readable<br />\n";
 223         }
 224
 225         // knowing that it might work..
 226         $md5 = md5($expression);
 227         $output .= "<p>base filename for expression is '$md5'</p>\n";
 228
 229         // temporary paths
 230         $tex = "$latex->temp_dir/$md5.tex";
 231         $dvi = "$latex->temp_dir/$md5.dvi";
 232         $ps = "$latex->temp_dir/$md5.ps";
 233         $img = "$latex->temp_dir/$md5.{$CFG->filter_tex_convertformat}";
 234
 235         // put the expression as a file into the temp area
 236         $expression = html_entity_decode($expression);
 237         $output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
 238         $doc = $latex->construct_latex_document($expression);
 239         $fh = fopen($tex, 'w');
 240         fputs($fh, $doc);
 241         fclose($fh);
 242
 243         // cd to temp dir
 244         chdir($latex->temp_dir);
 245
 246         // step 1: latex command
 247         $cmd = "$CFG->filter_tex_pathlatex --interaction=nonstopmode $tex";
 248         $output .= execute($cmd);
 249
 250         // step 2: dvips command
 251         $cmd = "$CFG->filter_tex_pathdvips -E $dvi -o $ps";
 252         $output .= execute($cmd);
 253
 254         // step 3: convert command
 255         $cmd = "$CFG->filter_tex_pathconvert -density 240 -trim $ps $img ";
 256         $output .= execute($cmd);
 257
 258         if (!$graphic) {
 259             echo $output;
 260         } else if (file_exists($img)){
 261             send_file($img, "$md5.{$CFG->filter_tex_convertformat}");
 262         } else {
 263             echo "Error creating image, see command execution output for more details.";
 264         }
 265     }
 266
 267     function execute($cmd) {
 268         exec($cmd, $result, $code);
 269         $output = "<pre>$ $cmd\n";
 270         $lines = implode("\n", $result);
 271         $output .= "OUTPUT: $lines\n";
 272         $output .= "RETURN CODE: $code\n</pre>\n";
 273         return $output;
 274     }
 275
 276     function slasharguments($texexp) {
 277         global $CFG;
 278         $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 279         $image = tex2image($texexp,true);
 280         echo "<p>If the following image displays correctly, set your ";
 281         echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 282         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 283         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php/$image\" align=\"absmiddle\"></p>\n";
 284         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 285         echo "It should display correctly as ";
 286         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 287         echo "<p>If neither equation image displays correctly, please seek ";
 288         echo "further help at moodle.org at the ";
 289         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 290         echo "Mathematics Tools Forum</a></p>";
 291     }
 292
 293 ?>
 294
 295 <html>
 296 <head><title>TeX Filter Debugger</title></head>
 297 <body>
 298   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 299        the text box below. (Click <a href="#help">here for help.</a>)
 300           <form action="texdebug.php" method="get"
 301            target="inlineframe">
 302             <center>
 303              <input type="text" name="tex" size="50"
 304                     value="f(x)=\int_{-\infty}^x~e^{-t^2}dt" />
 305             </center>
 306            <p>The following tests are available:</p>
 307            <ol>
 308            <li><input type="radio" name="action" value="ShowDB" id="ShowDB" />
 309                <label for="ShowDB">See the cache_filters database entry for this expression (if any).</label></li>
 310            <li><input type="radio" name="action" value="DeleteDB" id="DeleteDB" />
 311                <label for="DeleteDB">Delete the cache_filters database entry for this expression (if any).</label></li>
 312            <li><input type="radio" name="action" value="ShowImageMimetex" id="ShowImageMimetex"  checked="checked" />
 313                <label for="ShowImageMimetex">Show a graphic image of the algebraic expression rendered with mimetex.</label></li>
 314            <li><input type="radio" name="action" value="ShowImageTex" id="ShowImageTex" />
 315                <label for="ShowImageTex">Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</label></li>
 316            <li><input type="radio" name="action" value="ShowOutputTex" id="ShowOutputTex" />
 317                <label for="ShowOutputTex">Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</label></li>
 318            <li><input type="radio" name="action" value="SlashArguments" id="SlashArguments" />
 319                <label for="SlashArguments">Check slasharguments setting.</label></li>
 320            </ol>
 321            <input type="submit" value="Do it!" />
 322           </form> <br /> <br />
 323        <center>
 324           <iframe name="inlineframe" align="middle" width="80%" height="200">
 325           &lt;p&gt;Something is wrong...&lt;/p&gt;
 326           </iframe>
 327        </center> <br />
 328 <hr />
 329 <a name="help">
 330 <h2>Debugging Help</h2>
 331 </a>
 332 <p>First a brief overview of how the TeX filter works. The TeX filter first
 333 searches the database cache_filters table to see if this TeX expression had been
 334 processed before. If not, it adds a DB entry for that expression.  It then
 335 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 336 tag.  The filter/tex/pix.php script then searches the database to find an
 337 appropriate gif/png image file for that expression and to create one if it doesn't exist.
 338 It will then use either the LaTex/Ghostscript renderer (using external executables
 339 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
 340 renderer produces better results and is tried first.
 341 Here are a few common things that can go wrong and some suggestions on how
 342 you might try to fix them.</p>
 343 <ol>
 344 <li>Something had gone wrong on a previous occasion when the filter tried to
 345 process this expression. Then the database entry for that expression contains
 346 a bad TeX expression in the rawtext field (usually blank). You can fix this
 347 by clicking on &quot;Delete DB Entry&quot;</li>
 348 <li>The TeX to gif/png image conversion process does not work.
 349 If paths are specified in the filter configuation screen for the three
 350 executables these will be tried first. Note that they still must be correctly
 351 installed and have the correct permissions. In particular make sure that you
 352 have all the packages installed (e.g., on Debian/Ubuntu you need to install
 353 the 'tetex-extra' package). Running the 'show command execution' test should
 354 give a big clue.
 355 If this fails or is not available, the Mimetex executable is tried. If this
 356 fails a likely cause is that the mimetex binary you are using is
 357 incompatible with your operating system. You can try compiling it from the
 358 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 359 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 360 binary at <a href="http://moodle.org/download/mimetex/">
 361 http://moodle.org/download/mimetex/</a>. You may then also need to
 362 edit your moodle/filter/tex/pix.php file to add
 363 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 364 in the switch (PHP_OS) statement. Windows users may have a problem properly
 365 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 366 433152 bytes in size. If not, download a fresh copy from
 367 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 368 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
 369 Another possible problem which may affect
 370 both Unix and Windows servers is that the web server doesn't have execute permission
 371 on the mimetex binary. In that case change permissions accordingly</li>
 372 </ol>
 373 </body>
 374 </html>