filter/algebra/algebradebug.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/algebra', $filters) === FALSE) {
  15             error ('Filter not enabled!');
  16         }
  17     }
  18
  19     $CFG->texfilterdir = "filter/tex";
  20     $CFG->algebrafilterdir = "filter/algebra";
  21     $CFG->algebraimagedir = "filter/algebra";
  22     if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
  23       $CFG->algebrafilterdirwin = "filter\\algebra";
  24     }
  25
  26
  27     $query = urldecode($_SERVER['QUERY_STRING']);
  28     error_reporting(E_ALL);
  29
  30     if ($query) {
  31       $output = $query;
  32       $splitpos = strpos($query,'&')-8;
  33       $algebra = substr($query,8,$splitpos);
  34       $md5 = md5($algebra);
  35       if (strpos($query,'ShowDB') || strpos($query,'DeleteDB')) {
  36         $texcache = get_record("cache_filters","filter","algebra", "md5key", $md5);
  37       }
  38       if (strpos($query,'ShowDB')) {
  39         if ($texcache) {
  40           $output = "DB cache_filters entry for $algebra\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 $algebra not found\n";
  49         }
  50       }
  51       if (strpos($query,'DeleteDB')) {
  52         if ($texcache) {
  53           $output = "Deleting DB cache_filters entry for $algebra\n";
  54           $result =  delete_records("cache_filters","id",$texcache->id);
  55           if ($result) {
  56             $result = 1;
  57           } else {
  58             $result = 0;
  59           }
  60           $output .= "Number of records deleted = $result\n";
  61         } else {
  62           $output = "Could not delete DB cache_filters entry for $algebra\nbecause it could not be found.\n";
  63         }
  64       }
  65       if (strpos($query,'TeXStage1')) {
  66         $output = algebra2tex($algebra);
  67       }
  68       if (strpos($query,'TeXStage2')) {
  69         $output = algebra2tex($algebra);
  70         $output = refineTeX($output);
  71       }
  72       if (strpos($query,'ShowImage')||strpos($query,'SlashArguments')) {
  73         $output = algebra2tex($algebra);
  74         $output = refineTeX($output);
  75         if (strpos($query,'ShowImage')) {
  76           tex2image($output, $md5);
  77         } else {
  78           slasharguments($output, $md5);
  79         }
  80       } else {
  81         outputText($output);
  82       }
  83       exit;
  84     }
  85
  86 function algebra2tex($algebra) {
  87   global $CFG;
  88   $algebra = str_replace('&lt;','<',$algebra);
  89   $algebra = str_replace('&gt;','>',$algebra);
  90   $algebra = str_replace('<>','#',$algebra);
  91   $algebra = str_replace('<=','%',$algebra);
  92   $algebra = str_replace('>=','!',$algebra);
  93   $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
  94   $algebra = str_replace('delta','zdelta',$algebra);
  95   $algebra = str_replace('beta','bita',$algebra);
  96   $algebra = str_replace('theta','thita',$algebra);
  97   $algebra = str_replace('zeta','zita',$algebra);
  98   $algebra = str_replace('eta','xeta',$algebra);
  99   $algebra = str_replace('epsilon','zepslon',$algebra);
 100   $algebra = str_replace('upsilon','zupslon',$algebra);
 101   $algebra = preg_replace('!\r\n?!',' ',$algebra);
 102   $algebra = escapeshellarg($algebra);
 103
 104   if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
 105     $cmd  = "cd $CFG->dirroot\\$CFG->algebrafilterdirwin & algebra2tex.pl x/2";
 106     $test = `$cmd`;
 107     if ($test != '\frac{x}{2}') {
 108       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 109       $ecmd = $cmd . " 2>&1";
 110       echo `$ecmd` . "<br/>\n";
 111       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 112       $commandpath = "$CFG->dirroot\\$CFG->algebrafilterdirwin\\algebra2tex.pl";
 113       if (file_exists($commandpath)) {
 114         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 115       }
 116       die;
 117     }
 118     $cmd  = "cd $CFG->dirroot\\$CFG->algebrafilterdirwin & algebra2tex.pl $algebra";
 119   } else {
 120     $cmd  = "cd $CFG->dirroot/$CFG->algebrafilterdir; ./algebra2tex.pl x/2";
 121     $test = `$cmd`;
 122     if ($test != '\frac{x}{2}') {
 123       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 124       $ecmd = $cmd . " 2>&1";
 125       echo `$ecmd` . "<br/>\n";
 126       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 127       $commandpath = "$CFG->dirroot/$CFG->algebrafilterdir/algebra2tex.pl";
 128       if (file_exists($commandpath)) {
 129         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 130       }
 131       die;
 132     }
 133     $cmd  = "cd $CFG->dirroot/$CFG->algebrafilterdir; ./algebra2tex.pl $algebra";
 134   }
 135   $texexp = `$cmd`;
 136   return $texexp;
 137 }
 138
 139 function refineTeX($texexp) {
 140   $texexp = str_replace('zeroplace','',$texexp);
 141   $texexp = str_replace('#','\not= ',$texexp);
 142   $texexp = str_replace('%','\leq ',$texexp);
 143   $texexp = str_replace('!','\geq ',$texexp);
 144   $texexp = str_replace('\left{','{',$texexp);
 145   $texexp = str_replace('\right}','}',$texexp);
 146   $texexp = str_replace('\fun',' ',$texexp);
 147   $texexp = str_replace('infty','\infty',$texexp);
 148   $texexp = str_replace('alpha','\alpha',$texexp);
 149   $texexp = str_replace('gamma','\gamma',$texexp);
 150   $texexp = str_replace('iota','\iota',$texexp);
 151   $texexp = str_replace('kappa','\kappa',$texexp);
 152   $texexp = str_replace('lambda','\lambda',$texexp);
 153   $texexp = str_replace('mu','\mu',$texexp);
 154   $texexp = str_replace('nu','\nu',$texexp);
 155   $texexp = str_replace('xi','\xi',$texexp);
 156   $texexp = str_replace('rho','\rho',$texexp);
 157   $texexp = str_replace('sigma','\sigma',$texexp);
 158   $texexp = str_replace('tau','\tau',$texexp);
 159   $texexp = str_replace('phi','\phi',$texexp);
 160   $texexp = str_replace('chi','\chi',$texexp);
 161   $texexp = str_replace('psi','\psi',$texexp);
 162   $texexp = str_replace('omega','\omega',$texexp);
 163   $texexp = str_replace('zdelta','\delta',$texexp);
 164   $texexp = str_replace('bita','\beta',$texexp);
 165   $texexp = str_replace('thita','\theta',$texexp);
 166   $texexp = str_replace('zita','\zeta',$texexp);
 167   $texexp = str_replace('xeta','\eta',$texexp);
 168   $texexp = str_replace('zepslon','\epsilon',$texexp);
 169   $texexp = str_replace('zupslon','\upsilon',$texexp);
 170   $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
 171   $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
 172   $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
 173   $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
 174   $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
 175   $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
 176   $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
 177   $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
 178   $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
 179   $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
 180   $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
 181   $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
 182   $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
 183   $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
 184   $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
 185   $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
 186   $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
 187   $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
 188   $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
 189   $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
 190   return $texexp;
 191 }
 192
 193 function outputText($texexp) {
 194   header("Content-type: text/html");
 195   echo "<html><body><pre>\n";
 196   if ($texexp) {
 197     $texexp = str_replace('<','&lt;',$texexp);
 198     $texexp = str_replace('>','&gt;',$texexp);
 199     $texexp = str_replace('"','&quot;',$texexp);
 200     echo "$texexp\n\n";
 201   } else {
 202     echo "No text output available\n\n";
 203   }
 204   echo "</pre></body></html>\n";
 205 }
 206
 207 function tex2image($texexp, $md5, $return=false) {
 208     global $CFG;
 209     $error_message1 = "Your system is not configured to run mimeTeX. ";
 210     $error_message1 .= "You need to download the appropriate<br /> executable ";
 211     $error_message1 .= "from <a href=\"http://moodle.org/download/mimetex/\">";
 212     $error_message1 .= "http://moodle.org/download/mimetex/</a>, or obtain the ";
 213     $error_message1 .= "C source<br /> from <a href=\"http://www.forkosh.com/mimetex.zip\">";
 214     $error_message1 .= "http://www.forkosh.com/mimetex.zip</a>, compile it and ";
 215     $error_message1 .= "put the executable into your<br /> moodle/filter/tex/ directory. ";
 216     $error_message1 .= "You also need to edit your moodle/filter/algebra/pix.php file<br />";
 217     $error_message1 .= ' by adding the line<br /><pre>       case "' . PHP_OS . "\":\n";
 218     $error_message1 .= "           \$cmd = \"\\\\\"\$CFG->dirroot/\$CFG->texfilterdir/";
 219     $error_message1 .= 'mimetex.' . strtolower(PHP_OS) . "\\\\\" -e \\\\\"\$pathname\\\\\" \". escapeshellarg(\$texexp);";
 220     $error_message1 .= "</pre>You also need to add this to your algebradebug.php file.";
 221
 222     if ($texexp) {
 223         $texexp = '\Large ' . $texexp;
 224         $lifetime = 86400;
 225         $image  = $md5 . ".gif";
 226         $filetype = 'image/gif';
 227         if (!file_exists("$CFG->dataroot/$CFG->algebraimagedir")) {
 228             make_upload_directory($CFG->algebraimagedir);
 229         }
 230         $pathname = "$CFG->dataroot/$CFG->algebraimagedir/$image";
 231         if (file_exists($pathname)) {
 232             unlink($pathname);
 233         }
 234         $commandpath = "";
 235         $cmd = "";
 236         $texexp = escapeshellarg($texexp);
 237         switch (PHP_OS) {
 238             case "Linux":
 239                 $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.linux";
 240                 $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.linux\" -e \"$pathname\" $texexp";
 241             break;
 242             case "WINNT":
 243             case "WIN32":
 244             case "Windows":
 245                 $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.exe";
 246                 $cmd = str_replace(' ','^ ',$commandpath);
 247                 $cmd .= " ++ -e  \"$pathname\" $texexp";
 248             break;
 249             case "Darwin":
 250                 $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin";
 251                 $cmd = "\"$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin\" -e \"$pathname\" $texexp";
 252             break;
 253         }
 254         if (!$cmd) {
 255             if (is_executable("$CFG->dirroot/$CFG->texfilterdir/mimetex")) {   /// Use the custom binary
 256                 $commandpath="$CFG->dirroot/$CFG->texfilterdir/mimetex";
 257                 $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex -e $pathname $texexp";
 258             } else {
 259                 error($error_message1);
 260             }
 261         }
 262         system($cmd, $status);
 263     }
 264     if ($return) {
 265         return $image;
 266     }
 267     if ($texexp && file_exists($pathname)) {
 268            $lastmodified = filemtime($pathname);
 269            header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
 270            header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
 271            header("Cache-control: max_age = $lifetime"); // a day
 272            header("Pragma: ");
 273            header("Content-disposition: inline; filename=$image");
 274            header("Content-length: ".filesize($pathname));
 275            header("Content-type: $filetype");
 276            readfile("$pathname");
 277     } else {
 278            $ecmd = "$cmd 2>&1";
 279            echo `$ecmd` . "<br />\n";
 280            echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 281            if ($status == 4) {
 282              echo "Status corresponds to illegal instruction<br />\n";
 283            } else if ($status == 11) {
 284              echo "Status corresponds to bus error<br />\n";
 285            } else if ($status == 22) {
 286              echo "Status corresponds to abnormal termination<br />\n";
 287            }
 288            if (file_exists($commandpath)) {
 289               echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 290               echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 291               if (function_exists("md5_file")) {
 292                 echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 293               } else {
 294                 $handle = fopen($commandpath,"rb");
 295                 $contents = fread($handle,16384);
 296                 fclose($handle);
 297                 echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 298               }
 299            } else {
 300               echo "mimetex executable $commandpath not found!<br />";
 301            }
 302            echo "Image not found!";
 303     }
 304 }
 305
 306 function slasharguments($texexp, $md5) {
 307   global $CFG;
 308   $admin = $CFG->wwwroot . '/' . $CFG->admin . '/config.php';
 309   $image = tex2image($texexp,$md5,true);
 310   echo "<p>If the following image displays correctly, set your ";
 311   echo "<a href=\"$admin\" target=\"_blank\">Administration->Configuration->Variables</a> ";
 312   echo "setting for slasharguments to file.php/1/pic.jpg: ";
 313   echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 314   echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 315   echo "It should display correctly as ";
 316   echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 317   echo "<p>If neither equation image displays correctly, please seek ";
 318   echo "further help at moodle.org at the ";
 319   echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&username=guest\" target=\"_blank\">";
 320   echo "Mathematics Tools Forum</a></p>";
 321 }
 322
 323 ?>
 324
 325 <html>
 326 <head><title>Algebra Filter Debugger</title></head>
 327 <body>
 328     <p>Please enter an algebraic expression <b>without</b> any surrounding @@ into
 329        the text box below. (Click <a href="#help">here for help.</a>)
 330           <form action="algebradebug.php" method="get"
 331            target="inlineframe">
 332             <center>
 333              <input type="text" name="algebra" size="50"
 334                     value="sin(z)/(x^2+y^2)" />
 335             </center>
 336            <ol>
 337            <li>First click on this button <input type="submit" name="ShowDB" value="Show DB Entry" />
 338                to see the cache_filters database entry for this expression.</li>
 339            <li>If the database entry looks corrupt, click on this button to delete it:
 340                <input type="submit" name="DeleteDB" value="Delete DB Entry" /></li>
 341            <li>Now click on this button <input type="submit" name="TeXStage1" value="First Stage Tex Translation" />.
 342                A preliminary translation into TeX will appear in the box below.</li>
 343            <li>Next click on this button <input type="submit" name="TeXStage2" value="Second Stage Tex Translation" />.
 344                A more refined translation into TeX will appear in the box below.</li>
 345            <li>Then click on this button <input type="submit" name="ShowImage" value="Show Image" />
 346                to show a graphic image of the algebraic expression.</li>
 347            <li>Finally check your slash arguments setting
 348                <input type="submit" name="SlashArguments" value="Check Slash Arguments" /></li>
 349            </ol>
 350           </form> <br /> <br />
 351        <center>
 352           <iframe name="inlineframe" align="middle" width="80%" height="200">
 353           &lt;p&gt;Something is wrong...&lt;/p&gt;
 354           </iframe>
 355        </center> <br />
 356 <hr />
 357 <a name="help">
 358 <h2>Debugging Help</h2>
 359 </a>
 360 <p>First here is a brief overview on how the algebra filter works. It
 361 takes an algebra expression and first translates it into TeX.  It first
 362 looks for the TeX translation in the Moodle database in the table cache_filters
 363 in the field rawtext. If not found, it passes the algebraic expression to the
 364 Perl script algebra2tex.pl, which also uses the Perl library AlgParser.pm.
 365 It then saves the TeX translation in the database for subsequent uses and
 366 passes the TeX to the mimetex executable to be converted to a gif image.
 367 Here are a few common things that can go wrong and some suggestions on how
 368 you might try to fix them.</p>
 369 <ol>
 370 <li>Something had gone wrong on a previous occasion when the filter tried to
 371 translate this expression. Then the database entry for that expression contains
 372 a bad TeX translation in the rawtext field (usually blank). You can fix this
 373 by clicking on &quot;Delete DB Entry&quot;</li>
 374 <li>The First Stage TeX Translation gives a &quot;No text output available&quot;
 375 message. If your server is running Windows, this may be due to the fact that
 376 you haven't installed Perl or didn't install it correctly. If your server is
 377 running some version of Unix (e.g. Linux), then this may be due to your Perl
 378 binary being installed in a nonstandard location. To fix this edit the first
 379 line of the algebra2tex.pl script. Another possible problem which may affect
 380 both Unix and Windows servers is that the web server doesn't have execute permission
 381 on the algebra2tex.pl script. In that case change permissions accordingly</li>
 382 <li>The Second Stage TeX Translation produces malformed TeX. This indicates
 383 a bug in the algebra filter. Post the original algebraic expression and the
 384 bad TeX translation in the <a href="http://moodle.org/mod/forum/view.php?id=752">
 385 Mathematics Tools</a> forum in the Using Moodle course on moodle.org.</li>
 386 <li>The TeX to gif image conversion process does not work. If your server is
 387 running Unix, a likely cause is that the mimetex binary you are using is
 388 incompatible with your operating system. You can try compiling it from the
 389 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 390 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 391 binary at <a href="http://moodle.org/download/mimetex/">
 392 http://moodle.org/download/mimetex/</a>. You may then also need to
 393 edit your moodle/filter/algebra/pix.php file to add
 394 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 395 in the switch (PHP_OS) statement. Windows users may have a problem properly
 396 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 397 433152 bytes in size. If not, download fresh copy from
 398 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 399 http://moodle.org/download/mimetex/windows/mimetex.exe</a>. Lastly check
 400 the execute permissions on your mimetex binary, as outlined in item 2 above.</li>
 401 </ol>
 402 </body>
 403 </html>