documentation/moodle/texdebug_8php_source.html

00001 <?php
00002 // This file is part of Moodle - http://moodle.org/
00003 //
00004 // Moodle is free software: you can redistribute it and/or modify
00005 // it under the terms of the GNU General Public License as published by
00006 // the Free Software Foundation, either version 3 of the License, or
00007 // (at your option) any later version.
00008 //
00009 // Moodle is distributed in the hope that it will be useful,
00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012 // GNU General Public License for more details.
00013 //
00014 // You should have received a copy of the GNU General Public License
00015 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
00016
00029     require_once("../../config.php");
00030
00031     if (!filter_is_enabled('filter/tex')) {
00032         print_error('filternotenabled');
00033     }
00034
00035     require_once($CFG->libdir.'/filelib.php');
00036     require_once($CFG->dirroot.'/filter/tex/lib.php');
00037     require_once($CFG->dirroot.'/filter/tex/latex.php');
00038
00039     $action = optional_param('action', '', PARAM_ALPHA);
00040     $texexp = optional_param('tex', '', PARAM_RAW);
00041
00042     require_login();
00043     require_capability('moodle/site:config', get_context_instance(CONTEXT_SYSTEM), $USER->id);
00044
00045     $output = '';
00046
00047     // look up in cache if required
00048     if ($action=='ShowDB' or $action=='DeleteDB') {
00049         $md5 = md5($texexp);
00050         $texcache = $DB->get_record("cache_filters", array("filter"=>"tex", "md5key"=>$md5));
00051     }
00052
00053     // Action: Show DB Entry
00054     if ($action=='ShowDB') {
00055         if ($texcache) {
00056             $output = "DB cache_filters entry for $texexp\n";
00057             $output .= "id = $texcache->id\n";
00058             $output .= "filter = $texcache->filter\n";
00059             $output .= "version = $texcache->version\n";
00060             $output .= "md5key = $texcache->md5key\n";
00061             $output .= "rawtext = $texcache->rawtext\n";
00062             $output .= "timemodified = $texcache->timemodified\n";
00063         } else {
00064             $output = "DB cache_filters entry for $texexp not found\n";
00065         }
00066     }
00067
00068     // Action: Delete DB Entry
00069     if ($action=='DeleteDB') {
00070         if ($texcache) {
00071             $output = "Deleting DB cache_filters entry for $texexp\n";
00072             $result =  $DB->delete_records("cache_filters", array("id"=>$texcache->id));
00073             if ($result) {
00074                 $result = 1;
00075             } else {
00076                 $result = 0;
00077             }
00078             $output .= "Number of records deleted = $result\n";
00079         } else {
00080             $output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
00081         }
00082     }
00083
00084     // Action: Show Image
00085     if ($action=='ShowImageMimetex') {
00086         tex2image($texexp);
00087     }
00088
00089     // Action: Check Slasharguments
00090     if ($action=='SlashArguments') {
00091         slasharguments($texexp);
00092     }
00093
00094     // Action: Show Tex command line output
00095     if ($action=='ShowImageTex') {
00096         TexOutput($texexp, true);
00097         exit;
00098     }
00099
00100     // Action: Show Tex command line output
00101     if ($action=='ShowOutputTex') {
00102         if (debugging()) {
00103             TexOutput($texexp);
00104         } else {
00105             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
00106         }
00107         exit;
00108     }
00109
00110     if (!empty($action)) {
00111         outputText($output);
00112     }
00113
00114     // nothing more to do if there was any action
00115     if (!empty($action)) {
00116         exit;
00117     }
00118
00119
00120     function outputText($texexp) {
00121         header("Content-type: text/html; charset=utf-8");
00122         echo "<html><body><pre>\n";
00123         if ($texexp) {
00124             echo s($texexp)."\n\n";
00125         } else {
00126             echo "No text output available\n\n";
00127         }
00128         echo "</pre></body></html>\n";
00129     }
00130
00131     function tex2image($texexp, $return=false) {
00132         global $CFG;
00133
00134         if (!$texexp) {
00135             echo 'No tex expresion specified';
00136             return;
00137         }
00138
00139         $image  = md5($texexp) . ".gif";
00140         $filetype = 'image/gif';
00141         if (!file_exists("$CFG->dataroot/filter/tex")) {
00142             make_upload_directory("filter/tex");
00143         }
00144         $pathname = "$CFG->dataroot/filter/tex/$image";
00145         if (file_exists($pathname)) {
00146             unlink($pathname);
00147         }
00148
00149         $texexp = '\Large '.$texexp;
00150         $commandpath = filter_tex_get_executable(true);
00151         $cmd = filter_tex_get_cmd($pathname, $texexp);
00152         system($cmd, $status);
00153
00154         if ($return) {
00155           return $image;
00156         }
00157
00158         if (file_exists($pathname)) {
00159             send_file($pathname, $image);
00160
00161         } else if (debugging()) {
00162             $ecmd = "$cmd 2>&1";
00163             echo `$ecmd` . "<br />\n";
00164             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
00165             if ($status == 4) {
00166                 echo "Status corresponds to illegal instruction<br />\n";
00167             } else if ($status == 11) {
00168                 echo "Status corresponds to bus error<br />\n";
00169             } else if ($status == 22) {
00170                 echo "Status corresponds to abnormal termination<br />\n";
00171             }
00172             if (file_exists($commandpath)) {
00173                 echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
00174                 echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
00175                 if (function_exists("md5_file")) {
00176                     echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
00177                 } else {
00178                     $handle = fopen($commandpath,"rb");
00179                     $contents = fread($handle,16384);
00180                     fclose($handle);
00181                     echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
00182                 }
00183             } else {
00184                 echo "mimetex executable $commandpath not found!<br />";
00185             }
00186             echo "Image not found!";
00187         } else {
00188             echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
00189         }
00190     }
00191
00192
00193     // test Tex/Ghostscript output - command execution only
00194     function TexOutput($expression, $graphic=false) {
00195         global $CFG;
00196         $output = '';
00197
00198         $latex = new latex();
00199
00200         // first check if it is likely to work at all
00201         $output .= "<h3>Checking executables</h3>\n";
00202         $executables_exist = true;
00203         if (is_file($CFG->filter_tex_pathlatex)) {
00204             $output .= "latex executable ($CFG->filter_tex_pathlatex) is readable<br />\n";
00205         }
00206         else {
00207             $executables_exist = false;
00208             $output .= "<b>Error:</b> latex executable ($CFG->filter_tex_pathlatex) is not readable<br />\n";
00209         }
00210         if (is_file($CFG->filter_tex_pathdvips)) {
00211             $output .= "dvips executable ($CFG->filter_tex_pathdvips) is readable<br />\n";
00212         }
00213         else {
00214             $executables_exist = false;
00215             $output .= "<b>Error:</b> dvips executable ($CFG->filter_tex_pathdvips) is not readable<br />\n";
00216         }
00217         if (is_file($CFG->filter_tex_pathconvert)) {
00218             $output .= "convert executable ($CFG->filter_tex_pathconvert) is readable<br />\n";
00219         }
00220         else {
00221             $executables_exist = false;
00222             $output .= "<b>Error:</b> convert executable ($CFG->filter_tex_pathconvert) is not readable<br />\n";
00223         }
00224
00225         // knowing that it might work..
00226         $md5 = md5($expression);
00227         $output .= "<p>base filename for expression is '$md5'</p>\n";
00228
00229         // temporary paths
00230         $tex = "$latex->temp_dir/$md5.tex";
00231         $dvi = "$latex->temp_dir/$md5.dvi";
00232         $ps = "$latex->temp_dir/$md5.ps";
00233         $img = "$latex->temp_dir/$md5.{$CFG->filter_tex_convertformat}";
00234
00235         // put the expression as a file into the temp area
00236         $expression = html_entity_decode($expression);
00237         $output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
00238         $doc = $latex->construct_latex_document($expression);
00239         $fh = fopen($tex, 'w');
00240         fputs($fh, $doc);
00241         fclose($fh);
00242
00243         // cd to temp dir
00244         chdir($latex->temp_dir);
00245
00246         // step 1: latex command
00247         $cmd = "$CFG->filter_tex_pathlatex --interaction=nonstopmode $tex";
00248         $output .= execute($cmd);
00249
00250         // step 2: dvips command
00251         $cmd = "$CFG->filter_tex_pathdvips -E $dvi -o $ps";
00252         $output .= execute($cmd);
00253
00254         // step 3: convert command
00255         $cmd = "$CFG->filter_tex_pathconvert -density 240 -trim $ps $img ";
00256         $output .= execute($cmd);
00257
00258         if (!$graphic) {
00259             echo $output;
00260         } else if (file_exists($img)){
00261             send_file($img, "$md5.{$CFG->filter_tex_convertformat}");
00262         } else {
00263             echo "Error creating image, see command execution output for more details.";
00264         }
00265     }
00266
00267     function execute($cmd) {
00268         exec($cmd, $result, $code);
00269         $output = "<pre>$ $cmd\n";
00270         $lines = implode("\n", $result);
00271         $output .= "OUTPUT: $lines\n";
00272         $output .= "RETURN CODE: $code\n</pre>\n";
00273         return $output;
00274     }
00275
00276     function slasharguments($texexp) {
00277         global $CFG;
00278         $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
00279         $image = tex2image($texexp,true);
00280         echo "<p>If the following image displays correctly, set your ";
00281         echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
00282         echo "setting for slasharguments to file.php/1/pic.jpg: ";
00283         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php/$image\" align=\"absmiddle\"></p>\n";
00284         echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
00285         echo "It should display correctly as ";
00286         echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php?file=$image\" align=\"absmiddle\"></p>\n";
00287         echo "<p>If neither equation image displays correctly, please seek ";
00288         echo "further help at moodle.org at the ";
00289         echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
00290         echo "Mathematics Tools Forum</a></p>";
00291     }
00292
00293 ?>
00294
00295 <html>
00296 <head><title>TeX Filter Debugger</title></head>
00297 <body>
00298   <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
00299        the text box below. (Click <a href="#help">here for help.</a>)
00300           <form action="texdebug.php" method="get"
00301            target="inlineframe">
00302             <center>
00303              <input type="text" name="tex" size="50"
00304                     value="f(x)=\int_{-\infty}^x~e^{-t^2}dt" />
00305             </center>
00306            <p>The following tests are available:</p>
00307            <ol>
00308            <li><input type="radio" name="action" value="ShowDB" id="ShowDB" />
00309                <label for="ShowDB">See the cache_filters database entry for this expression (if any).</label></li>
00310            <li><input type="radio" name="action" value="DeleteDB" id="DeleteDB" />
00311                <label for="DeleteDB">Delete the cache_filters database entry for this expression (if any).</label></li>
00312            <li><input type="radio" name="action" value="ShowImageMimetex" id="ShowImageMimetex"  checked="checked" />
00313                <label for="ShowImageMimetex">Show a graphic image of the algebraic expression rendered with mimetex.</label></li>
00314            <li><input type="radio" name="action" value="ShowImageTex" id="ShowImageTex" />
00315                <label for="ShowImageTex">Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</label></li>
00316            <li><input type="radio" name="action" value="ShowOutputTex" id="ShowOutputTex" />
00317                <label for="ShowOutputTex">Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</label></li>
00318            <li><input type="radio" name="action" value="SlashArguments" id="SlashArguments" />
00319                <label for="SlashArguments">Check slasharguments setting.</label></li>
00320            </ol>
00321            <input type="submit" value="Do it!" />
00322           </form> <br /> <br />
00323        <center>
00324           <iframe name="inlineframe" align="middle" width="80%" height="200">
00325           &lt;p&gt;Something is wrong...&lt;/p&gt;
00326           </iframe>
00327        </center> <br />
00328 <hr />
00329 <a name="help">
00330 <h2>Debugging Help</h2>
00331 </a>
00332 <p>First a brief overview of how the TeX filter works. The TeX filter first
00333 searches the database cache_filters table to see if this TeX expression had been
00334 processed before. If not, it adds a DB entry for that expression.  It then
00335 replaces the TeX expression by an &lt;img src=&quot;.../filter/tex/pix.php...&quot;&gt;
00336 tag.  The filter/tex/pix.php script then searches the database to find an
00337 appropriate gif/png image file for that expression and to create one if it doesn't exist.
00338 It will then use either the LaTex/Ghostscript renderer (using external executables
00339 on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
00340 renderer produces better results and is tried first.
00341 Here are a few common things that can go wrong and some suggestions on how
00342 you might try to fix them.</p>
00343 <ol>
00344 <li>Something had gone wrong on a previous occasion when the filter tried to
00345 process this expression. Then the database entry for that expression contains
00346 a bad TeX expression in the rawtext field (usually blank). You can fix this
00347 by clicking on &quot;Delete DB Entry&quot;</li>
00348 <li>The TeX to gif/png image conversion process does not work.
00349 If paths are specified in the filter configuation screen for the three
00350 executables these will be tried first. Note that they still must be correctly
00351 installed and have the correct permissions. In particular make sure that you
00352 have all the packages installed (e.g., on Debian/Ubuntu you need to install
00353 the 'tetex-extra' package). Running the 'show command execution' test should
00354 give a big clue.
00355 If this fails or is not available, the Mimetex executable is tried. If this
00356 fails a likely cause is that the mimetex binary you are using is
00357 incompatible with your operating system. You can try compiling it from the
00358 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
00359 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
00360 binary at <a href="http://moodle.org/download/mimetex/">
00361 http://moodle.org/download/mimetex/</a>. You may then also need to
00362 edit your moodle/filter/tex/pix.php file to add
00363 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
00364 in the switch (PHP_OS) statement. Windows users may have a problem properly
00365 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
00366 433152 bytes in size. If not, download a fresh copy from
00367 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
00368 http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
00369 Another possible problem which may affect
00370 both Unix and Windows servers is that the web server doesn't have execute permission
00371 on the mimetex binary. In that case change permissions accordingly</li>
00372 </ol>
00373 </body>
00374 </html>