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Differences Between: [Versions 311 and 401] [Versions 311 and 402] [Versions 311 and 403]

   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>