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