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     require_once("../../config.php");
   7
   8     if (empty($CFG->textfilters)) {
   9         error ('Filter not enabled!');
  10     } else {
  11         $filters = explode(',', $CFG->textfilters);
  12         if (array_search('filter/tex', $filters) === FALSE) {
  13             error ('Filter not enabled!');
  14         }
  15     }
  16
  17     require_once($CFG->libdir.'/filelib.php');
  18     require_once($CFG->dirroot.'/filter/tex/lib.php');
  19     require_once($CFG->dirroot.'/filter/tex/latex.php');
  20
  21     $action = optional_param('action', '', PARAM_ALPHA);
  22     $texexp = optional_param('tex', '', PARAM_RAW);
  23
  24     require_login();
  25     require_capability('moodle/site:config', get_context_instance(CONTEXT_SYSTEM), $USER->id); /// Required cap to run this. MDL-18552
  26
  27     $query = urldecode($_SERVER['QUERY_STRING']);
  28     error_reporting(E_ALL);
  29     $output = '';
  30
  31     // look up in cache if required
  32     if ($action=='ShowDB' or $action=='DeleteDB') {
  33         $md5 = md5($texexp);
  34         $texcache = get_record("cache_filters","filter","tex", "md5key", $md5);
  35     }
  36
  37     // Action: Show DB Entry
  38     if ($action=='ShowDB') {
  39         if ($texcache) {
  40             $output = "DB cache_filters entry for $texexp\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 $texexp not found\n";
  49         }
  50     }
  51
  52     // Action: Delete DB Entry
  53     if ($action=='DeleteDB') {
  54         if ($texcache) {
  55             $output = "Deleting DB cache_filters entry for $texexp\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 $texexp\nbecause it could not be found.\n";
  65         }
  66     }
  67
  68     // Action: Show Image
  69     if ($action=='ShowImageMimetex') {
  70         tex2image($texexp);
  71     }
  72
  73     // Action: Check Slasharguments
  74     if ($action=='SlashArguments') {
  75         slasharguments($texexp);
  76     }
  77
  78     // Action: Show Tex command line output
  79     if ($action=='ShowImageTex') {
  80         TexOutput($texexp, true);
  81         exit;
  82     }
  83
  84     // Action: Show Tex command line output
  85     if ($action=='ShowOutputTex') {
  86         if (debugging()) {
  87             TexOutput($texexp);
  88         } else {
  89             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
  90         }
  91         exit;
  92     }
  93
  94     if (!empty($action)) {
  95         outputText($output);
  96     }
  97
  98     // nothing more to do if there was any action
  99     if (!empty($action)) {
 100         exit;
 101     }
 102
 103
 104     function outputText($texexp) {
 105         header("Content-type: text/html");
 106         echo "<html><body><pre>\n";
 107         if ($texexp) {
 108             $texexp = str_replace('<', '&lt;', $texexp);
 109             $texexp = str_replace('>', '&gt;', $texexp);
 110             $texexp = str_replace('"', '&quot;', $texexp);
 111             echo "$texexp\n\n";
 112         } else {
 113             echo "No text output available\n\n";
 114         }
 115         echo "</pre></body></html>\n";
 116     }
 117
 118     function tex2image($texexp, $return=false) {
 119         global $CFG;
 120
 121         if (!$texexp) {
 122             echo 'No tex expresion specified';
 123             return;
 124         }
 125
 126         $image  = md5($texexp) . ".gif";
 127         $filetype = 'image/gif';
 128         if (!file_exists("$CFG->dataroot/filter/tex")) {
 129             make_upload_directory("filter/tex");
 130         }
 131         $pathname = "$CFG->dataroot/filter/tex/$image";
 132         if (file_exists($pathname)) {
 133             unlink($pathname);
 134         }
 135
 136         $texexp = '\Large '.$texexp;
 137         $commandpath = tex_filter_get_executable(true);
 138         $cmd = tex_filter_get_cmd($pathname, $texexp);
 139         system($cmd, $status);
 140
 141         if ($return) {
 142           return $image;
 143         }
 144
 145         if (file_exists($pathname)) {
 146             send_file($pathname, $image);
 147
 148         } else if (debugging()) {
 149             $ecmd = "$cmd 2>&1";
 150             echo `$ecmd` . "<br />\n";
 151             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 152             if ($status == 4) {
 153                 echo "Status corresponds to illegal instruction<br />\n";
 154             } else if ($status == 11) {
 155                 echo "Status corresponds to bus error<br />\n";
 156             } else if ($status == 22) {
 157                 echo "Status corresponds to abnormal termination<br />\n";
 158             }
 159             if (file_exists($commandpath)) {
 160                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 161                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 162                 if (function_exists("md5_file")) {
 163                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 164                 } else {
 165                     $handle = fopen($commandpath,"rb");
 166                     $contents = fread($handle,16384);
 167                     fclose($handle);
 168                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 169                 }
 170             } else {
 171                 echo "mimetex executable $commandpath not found!<br />";
 172             }
 173             echo "Image not found!";
 174         } else {
 175             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
 176         }
 177     }
 178
 179
 180     // test Tex/Ghostscript output - command execution only
 181     function TexOutput($expression, $graphic=false) {
 182         global $CFG;
 183         $output = '';
 184
 185         $latex = new latex();
 186
 187         // first check if it is likely to work at all
 188         $output .= "<h3>Checking executables</h3>\n";
 189         $executables_exist = true;
 190         if (is_file($CFG->filter_tex_pathlatex)) {
 191             $output .= "latex executable ($CFG->filter_tex_pathlatex) is readable<br />\n";
 192         }
 193         else {
 194             $executables_exist = false;
 195             $output .= "<b>Error:</b> latex executable ($CFG->filter_tex_pathlatex) is not readable<br />\n";
 196         }
 197         if (is_file($CFG->filter_tex_pathdvips)) {
 198             $output .= "dvips executable ($CFG->filter_tex_pathdvips) is readable<br />\n";
 199         }
 200         else {
 201             $executables_exist = false;
 202             $output .= "<b>Error:</b> dvips executable ($CFG->filter_tex_pathdvips) is not readable<br />\n";
 203         }
 204         if (is_file($CFG->filter_tex_pathconvert)) {
 205             $output .= "convert executable ($CFG->filter_tex_pathconvert) is readable<br />\n";
 206         }
 207         else {
 208             $executables_exist = false;
 209             $output .= "<b>Error:</b> convert executable ($CFG->filter_tex_pathconvert) is not readable<br />\n";
 210         }
 211
 212         // knowing that it might work..
 213         $md5 = md5($expression);
 214         $output .= "<p>base filename for expression is '$md5'</p>\n";
 215
 216         // temporary paths
 217         $tex = "$latex->temp_dir/$md5.tex";
 218         $dvi = "$latex->temp_dir/$md5.dvi";
 219         $ps = "$latex->temp_dir/$md5.ps";
 220         $gif = "$latex->temp_dir/$md5.gif";
 221
 222         // put the expression as a file into the temp area
 223         $expression = stripslashes($expression);
 224         $expression = html_entity_decode($expression);
 225         $output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
 226         $doc = $latex->construct_latex_document($expression);
 227         $fh = fopen($tex, 'w');
 228         fputs($fh, $doc);
 229         fclose($fh);
 230
 231         // cd to temp dir
 232         chdir($latex->temp_dir);
 233
 234         // step 1: latex command
 235         $cmd = "$CFG->filter_tex_pathlatex --interaction=nonstopmode $tex";
 236         $output .= execute($cmd);
 237
 238         // step 2: dvips command
 239         $cmd = "$CFG->filter_tex_pathdvips -E $dvi -o $ps";
 240         $output .= execute($cmd);
 241
 242         // step 3: convert command
 243         $cmd = "$CFG->filter_tex_pathconvert -density 240 -trim $ps $gif ";
 244         $output .= execute($cmd);
 245
 246         if (!$graphic) {
 247             echo($output);
 248         } else {
 249             send_file($gif, "$md5.gif");
 250          }
 251     }
 252
 253     function execute($cmd) {
 254         exec($cmd, $result, $code);
 255         $output = "<pre>$ $cmd\n";
 256         $lines = implode("\n", $result);
 257         $output .= "OUTPUT: $lines\n";
 258         $output .= "RETURN CODE: $code\n</pre>\n";
 259         return $output;
 260     }
 261
 262     function slasharguments($texexp) {
 263         global $CFG;
 264         $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 265         $image = tex2image($texexp,true);
 266         echo "<p>If the following image displays correctly, set your ";
 267         echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 268         echo "setting for slasharguments to file.php/1/pic.jpg: ";
 269         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php/$image\" align=\"absmiddle\"></p>\n";
 270         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 271         echo "It should display correctly as ";
 272         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 273         echo "<p>If neither equation image displays correctly, please seek ";
 274         echo "further help at moodle.org at the ";
 275         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 276         echo "Mathematics Tools Forum</a></p>";
 277     }
 278
 279 ?>
 280
 281 <html>
 282 <head><title>TeX Filter Debugger</title></head>
 283 <body>
 284   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
 285        the text box below. (Click <a href="#help">here for help.</a>)
 286           <form action="texdebug.php" method="get"
 287            target="inlineframe">
 288             <center>
 289              <input type="text" name="tex" size="50"
 290                     value="f(x)=\Bigint_{-\infty}^x~e^{-t^2}dt" />
 291             </center>
 292            <p>The following tests are available:</p>
 293            <ol>
 294            <li><input type="radio" name="action" value="ShowDB" id="ShowDB" />
 295                <label for="ShowDB">See the cache_filters database entry for this expression (if any).</label></li>
 296            <li><input type="radio" name="DeleteDB" value="DeleteDB" id="DeleteDB" />
 297                <label for="DeleteDB">Delete the cache_filters database entry for this expression (if any).</label></li>
 298            <li><input type="radio" name="action" value="ShowImageMimetex" id="ShowImageMimetex"  checked="checked" />
 299                <label for="ShowImageMimetex">Show a graphic image of the algebraic expression rendered with mimetex.</label></li>
 300            <li><input type="radio" name="action" value="ShowImageTex" id="ShowImageTex" />
 301                <label for="ShowImageTex">Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</label></li>
 302            <li><input type="radio" name="action" value="ShowOutputTex" id="ShowOutputTex" />
 303                <label for="ShowOutputTex">Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</label></li>
 304            <li><input type="radio" name="action" value="SlashArguments" id="SlashArguments" />
 305                <label for="SlashArguments">Check slasharguments setting.</label></li>
 306            </ol>
 307            <input type="submit" value="Do it!" />
 308           </form> <br /> <br />
 309        <center>
 310           <iframe name="inlineframe" align="middle" width="80%" height="200">
 311           &lt;p&gt;Something is wrong...&lt;/p&gt;
 312           </iframe>
 313        </center> <br />
 314 <hr />
 315 <a name="help">
 316 <h2>Debugging Help</h2>
 317 </a>
 318 <p>First a brief overview of how the TeX filter works. The TeX filter first
 319 searches the database cache_filters table to see if this TeX expression had been
 320 processed before. If not, it adds a DB entry for that expression.  It then
 321 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
 322 tag.  The filter/tex/pix.php script then searches the database to find an
 323 appropriate gif image file for that expression and to create one if it doesn't exist.
 324 It will then use either the LaTex/Ghostscript renderer (using external executables
 325 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
 326 renderer produces better results and is tried first.
 327 Here are a few common things that can go wrong and some suggestions on how
 328 you might try to fix them.</p>
 329 <ol>
 330 <li>Something had gone wrong on a previous occasion when the filter tried to
 331 process this expression. Then the database entry for that expression contains
 332 a bad TeX expression in the rawtext field (usually blank). You can fix this
 333 by clicking on &quot;Delete DB Entry&quot;</li>
 334 <li>The TeX to gif image conversion process does not work.
 335 If paths are specified in the filter configuation screen for the three
 336 executables these will be tried first. Note that they still must be correctly
 337 installed and have the correct permissions. In particular make sure that you
 338 have all the packages installed (e.g., on Debian/Ubuntu you need to install
 339 the 'tetex-extra' package). Running the 'show command execution' test should
 340 give a big clue.
 341 If this fails or is not available, the Mimetex executable is tried. If this
 342 fails a likely cause is that the mimetex binary you are using is
 343 incompatible with your operating system. You can try compiling it from the
 344 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 345 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 346 binary at <a href="http://moodle.org/download/mimetex/">
 347 http://moodle.org/download/mimetex/</a>. You may then also need to
 348 edit your moodle/filter/tex/pix.php file to add
 349 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 350 in the switch (PHP_OS) statement. Windows users may have a problem properly
 351 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 352 433152 bytes in size. If not, download a fresh copy from
 353 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 354 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
 355 Another possible problem which may affect
 356 both Unix and Windows servers is that the web server doesn't have execute permission
 357 on the mimetex binary. In that case change permissions accordingly</li>
 358 </ol>
 359 </body>
 360 </html>