MDL-52954 core: Change from pandoc to unoconv - it gives better results

Most importantly it retains formatting better, and supports different charsets far better than pandoc.

admin/settings/server.php

@@ -12,7 +12,7 @@
 $temp->add(new admin_setting_configexecutable('aspellpath', new lang_string('aspellpath', 'admin'), new lang_string('edhelpaspellpath'), ''));
 $temp->add(new admin_setting_configexecutable('pathtodot', new lang_string('pathtodot', 'admin'), new lang_string('pathtodot_help', 'admin'), ''));
 $temp->add(new admin_setting_configexecutable('pathtogs', new lang_string('pathtogs', 'admin'), new lang_string('pathtogs_help', 'admin'), '/usr/bin/gs'));
-$temp->add(new admin_setting_configexecutable('pathtopandoc', new lang_string('pathtopandoc', 'admin'), new lang_string('pathtopandoc_help', 'admin'), '/usr/bin/pandoc'));
+$temp->add(new admin_setting_configexecutable('pathtounoconv', new lang_string('pathtounoconv', 'admin'), new lang_string('pathtounoconv_help', 'admin'), '/usr/bin/unoconv'));
 $ADMIN->add('server', $temp);
 
 

config-dist.php

@@ -838,11 +838,11 @@
 // (Development->Profiling) built into Moodle.
 //      $CFG->pathtodot = '';
 //
-// Path to pandoc.
-// Probably something like /usr/bin/pandoc. Used to convert between document formats.
-// It is recommended to install the latest stable release of pandoc.
-// Download packages for all platforms are available from http://pandoc.org/
-//      $CFG->pathtopandoc = '';
+// Path to unoconv.
+// Probably something like /usr/bin/unoconv. Used as a fallback to convert between document formats.
+// Unoconv is used convert between file formats supported by LibreOffice.
+// Use a recent version of unoconv ( >= 0.7 ), older versions have trouble running from a webserver.
+//      $CFG->pathtounoconv = '';
 
 //=========================================================================
 // ALL DONE!  To continue installation, visit your main page with a browser

lang/en/admin.php

@@ -779,8 +779,6 @@
 $string['passwordresettime'] = 'Maximum time to validate password reset request';
 $string['passwordreuselimit'] = 'Password rotation limit';
 $string['passwordreuselimit_desc'] = 'Number of times a user must change their password before they are allowed to reuse a password. Hashes of previously used passwords are stored in local database table. This feature might not be compatible with some external authentication plugins.';
-$string['pathtopandoc'] = 'Path to pandoc document converter';
-$string['pathtopandoc_help'] = 'Path to pandoc document converter. This is an executable that is capable of converting between document formats. This is optional, but if specified, Moodle will be able to perform automated conversion of documents from a wide range of file formats. This is used by the Assignment module "Annotate PDF" feature.';
 $string['pathtodot'] = 'Path to dot';
 $string['pathtodot_help'] = 'Path to dot. Probably something like /usr/bin/dot. To be able to generate graphics from DOT files, you must have installed the dot executable and point to it here. Note that, for now, this only used by the profiling features (Development->Profiling) built into Moodle.';
 $string['pathtodu'] = 'Path to du';
@@ -792,6 +790,8 @@
 $string['pathtopsql'] = 'Path to psql';
 $string['pathtopsqldesc'] = 'This is only necessary to enter if you have more than one psql on your system (for example if you have more than one version of postgresql installed)';
 $string['pathtopsqlinvalid'] = 'Invalid path to psql - either wrong path or not executable';
+$string['pathtounoconv'] = 'Path to unoconv document converter';
+$string['pathtounoconv_help'] = 'Path to unoconv document converter. This is an executable that is capable of converting between document formats supported by LibreOffice. This is optional, but if specified, Moodle will use it to automatically convert between document formats. This is used to support a wider range of input files for the assignment annotate PDF feature.';
 $string['pcreunicodewarning'] = 'It is strongly recommended to use PCRE PHP extension that is compatible with Unicode characters.';
 $string['perfdebug'] = 'Performance info';
 $string['performance'] = 'Performance';

lib/behat/lib.php

@@ -166,7 +166,7 @@ function behat_clean_init_config() {
         'umaskpermissions', 'dbtype', 'dblibrary', 'dbhost', 'dbname', 'dbuser', 'dbpass', 'prefix',
         'dboptions', 'proxyhost', 'proxyport', 'proxytype', 'proxyuser', 'proxypassword',
         'proxybypass', 'theme', 'pathtogs', 'pathtodu', 'aspellpath', 'pathtodot', 'skiplangupgrade',
-        'altcacheconfigpath', 'pathtopandoc'
+        'altcacheconfigpath', 'pathtounoconv'
     ));
 
     // Add extra allowed settings.

lib/filestorage/file_storage.php

@@ -187,22 +187,30 @@ public function get_converted_document(stored_file $file, $format) {
      * @param string $format The desired format - e.g. 'pdf'. Formats are specified by file extension.
      * @return bool - True if the format is supported for input.
      */
-    protected function is_input_format_supported_by_pandoc($format) {
-        $sanitized = trim(strtolower($format));
-        return in_array($sanitized, array('md', 'html', 'tex', 'docx', 'odt', 'epub', 'png', 'jpg', 'gif'));
-    }
+    protected function is_format_supported_by_unoconv($format) {
+        global $CFG;
+
+        if (!isset($this->unoconvformats)) {
+            // Ask unoconv for it's list of supported document formats.
+            $cmd = escapeshellcmd(trim($CFG->pathtounoconv)) . ' --show';
+            $pipes = array();
+            $pipesspec = array(2 => array('pipe', 'w'));
+            $proc = proc_open($cmd, $pipesspec, $pipes);
+            $programoutput = stream_get_contents($pipes[2]);
+            fclose($pipes[2]);
+            proc_close($proc);
+            $matches = array();
+            preg_match_all('/\[\.(.*)\]/', $programoutput, $matches);
+
+            $this->unoconvformats = $matches[1];
+            $this->unoconvformats = array_unique($this->unoconvformats);
+        }
 
-    /**
-     * Verify the format is supported.
-     *
-     * @param string $format The desired format - e.g. 'pdf'. Formats are specified by file extension.
-     * @return bool - True if the format is supported for output.
-     */
-    protected function is_output_format_supported_by_pandoc($format) {
         $sanitized = trim(strtolower($format));
-        return in_array($sanitized, array('md', 'pdf', 'html', 'tex', 'docx', 'odt', 'odf', 'epub'));
+        return in_array($sanitized, $this->unoconvformats);
     }
 
+
     /**
      * Perform a file format conversion on the specified document.
      *
@@ -213,17 +221,17 @@ protected function is_output_format_supported_by_pandoc($format) {
     protected function create_converted_document(stored_file $file, $format) {
         global $CFG;
 
-        if (empty($CFG->pathtopandoc) || !is_executable(trim($CFG->pathtopandoc))) {
+        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return false;
         }
 
         $fileextension = strtolower(pathinfo($file->get_filename(), PATHINFO_EXTENSION));
-        if (!self::is_input_format_supported_by_pandoc($fileextension)) {
+        if (!self::is_format_supported_by_unoconv($fileextension)) {
             return false;
         }
 
-        if (!self::is_output_format_supported_by_pandoc($format)) {
+        if (!self::is_format_supported_by_unoconv($format)) {
             return false;
         }
 
@@ -236,21 +244,14 @@ protected function create_converted_document(stored_file $file, $format) {
         $filename = $tmp . '/' . $localfilename;
         $file->copy_content_to($filename);
 
-        if (in_array($fileextension, array('gif', 'jpg', 'png'))) {
-            // We wrap images in a tiny html file - pandoc will generate documents from them.
-            $htmlwrapperfile = $tmp . '/wrapper.html';
-
-            file_put_contents($htmlwrapperfile, "<html><body><img src=\"$localfilename\"></body></html>");
-
-            $filename = $htmlwrapperfile;
-        }
-
         $newtmpfile = pathinfo($filename, PATHINFO_FILENAME) . '.' . $format;
 
         // Safety.
         $newtmpfile = $tmp . '/' . clean_param($newtmpfile, PARAM_FILE);
 
-        $cmd = escapeshellcmd(trim($CFG->pathtopandoc)) . ' ' .
+        $cmd = escapeshellcmd(trim($CFG->pathtounoconv)) . ' ' .
+               escapeshellarg('-f') . ' ' .
+               escapeshellarg($format) . ' ' .
                escapeshellarg('-o') . ' ' .
                escapeshellarg($newtmpfile) . ' ' .
                escapeshellarg($filename);
@@ -259,6 +260,7 @@ protected function create_converted_document(stored_file $file, $format) {
         $output = null;
         $currentdir = getcwd();
         chdir($tmp);
+        $result = exec('env 1>&2', $output);
         $result = exec($cmd, $output);
         chdir($currentdir);
         if (!file_exists($newtmpfile)) {

lib/phpunit/bootstrap.php

@@ -186,7 +186,7 @@
                  'dbtype', 'dblibrary', 'dbhost', 'dbname', 'dbuser', 'dbpass', 'prefix', 'dboptions',
                  'proxyhost', 'proxyport', 'proxytype', 'proxyuser', 'proxypassword', 'proxybypass', // keep proxy settings from config.php
                  'altcacheconfigpath', 'pathtogs', 'pathtodu', 'aspellpath', 'pathtodot',
-                 'pathtopandoc'
+                 'pathtounoconv'
                 );
 $productioncfg = (array)$CFG;
 $CFG = new stdClass();

lib/tests/pandoc_test.php → lib/tests/unoconv_test.php

@@ -15,7 +15,7 @@
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
 /**
- * Test pandoc functionality.
+ * Test unoconv functionality.
  *
  * @package    core
  * @category   phpunit
@@ -27,14 +27,14 @@
 
 
 /**
- * A set of tests for some of the pandoc functionality within Moodle.
+ * A set of tests for some of the unoconv functionality within Moodle.
  *
  * @package    core
  * @category   phpunit
  * @copyright  2016 Damyon Wiese
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class core_pandoc_testcase extends advanced_testcase {
+class core_unoconv_testcase extends advanced_testcase {
 
     private $testfile1 = null;
     private $testfile2 = null;
@@ -51,7 +51,7 @@ public function setUp() {
             'filepath' => '/',
             'filename' => 'test.html'
         );
-        $teststring = file_get_contents($this->fixturepath . DIRECTORY_SEPARATOR . 'pandoc-source.html');
+        $teststring = file_get_contents($this->fixturepath . DIRECTORY_SEPARATOR . 'unoconv-source.html');
         $this->testfile1 = $fs->create_file_from_string($filerecord, $teststring);
 
         $filerecord = array(
@@ -62,7 +62,7 @@ public function setUp() {
             'filepath' => '/',
             'filename' => 'test.docx'
         );
-        $teststring = file_get_contents($this->fixturepath . DIRECTORY_SEPARATOR . 'pandoc-source.docx');
+        $teststring = file_get_contents($this->fixturepath . DIRECTORY_SEPARATOR . 'unoconv-source.docx');
         $this->testfile2 = $fs->create_file_from_string($filerecord, $teststring);
 
         $this->resetAfterTest();
@@ -71,33 +71,37 @@ public function setUp() {
     public function test_generate_pdf() {
         global $CFG;
 
-        if (empty($CFG->pathtopandoc) || !is_executable(trim($CFG->pathtopandoc))) {
+        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return $this->markTestSkipped();
         }
         $fs = get_file_storage();
 
         $result = $fs->get_converted_document($this->testfile1, 'pdf');
+        $this->assertNotFalse($result);
         $this->assertSame($result->get_mimetype(), 'application/pdf');
         $this->assertGreaterThan(0, $result->get_filesize());
         $result = $fs->get_converted_document($this->testfile2, 'pdf');
+        $this->assertNotFalse($result);
         $this->assertSame($result->get_mimetype(), 'application/pdf');
         $this->assertGreaterThan(0, $result->get_filesize());
     }
 
     public function test_generate_markdown() {
         global $CFG;
 
-        if (empty($CFG->pathtopandoc) || !is_executable(trim($CFG->pathtopandoc))) {
+        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return $this->markTestSkipped();
         }
         $fs = get_file_storage();
 
-        $result = $fs->get_converted_document($this->testfile1, 'md');
+        $result = $fs->get_converted_document($this->testfile1, 'txt');
+        $this->assertNotFalse($result);
         $this->assertSame($result->get_mimetype(), 'text/plain');
         $this->assertGreaterThan(0, $result->get_filesize());
-        $result = $fs->get_converted_document($this->testfile2, 'md');
+        $result = $fs->get_converted_document($this->testfile2, 'txt');
+        $this->assertNotFalse($result);
         $this->assertSame($result->get_mimetype(), 'text/plain');
         $this->assertGreaterThan(0, $result->get_filesize());
     }

mod/assign/feedback/editpdf/classes/document_services.php

@@ -53,6 +53,30 @@ class document_services {
     /** Filename for combined pdf */
     const COMBINED_PDF_FILENAME = 'combined.pdf';
 
+    /** Base64 encoded blank pdf. This is the most reliable/fastest way to generate a blank pdf. */
+    const BLANK_PDF_BASE64 = <<<EOD
+JVBERi0xLjQKJcOkw7zDtsOfCjIgMCBvYmoKPDwvTGVuZ3RoIDMgMCBSL0ZpbHRlci9GbGF0ZURl
+Y29kZT4+CnN0cmVhbQp4nDPQM1Qo5ypUMFAwALJMLU31jBQsTAz1LBSKUrnCtRTyuAIVAIcdB3IK
+ZW5kc3RyZWFtCmVuZG9iagoKMyAwIG9iago0MgplbmRvYmoKCjUgMCBvYmoKPDwKPj4KZW5kb2Jq
+Cgo2IDAgb2JqCjw8L0ZvbnQgNSAwIFIKL1Byb2NTZXRbL1BERi9UZXh0XQo+PgplbmRvYmoKCjEg
+MCBvYmoKPDwvVHlwZS9QYWdlL1BhcmVudCA0IDAgUi9SZXNvdXJjZXMgNiAwIFIvTWVkaWFCb3hb
+MCAwIDU5NSA4NDJdL0dyb3VwPDwvUy9UcmFuc3BhcmVuY3kvQ1MvRGV2aWNlUkdCL0kgdHJ1ZT4+
+L0NvbnRlbnRzIDIgMCBSPj4KZW5kb2JqCgo0IDAgb2JqCjw8L1R5cGUvUGFnZXMKL1Jlc291cmNl
+cyA2IDAgUgovTWVkaWFCb3hbIDAgMCA1OTUgODQyIF0KL0tpZHNbIDEgMCBSIF0KL0NvdW50IDE+
+PgplbmRvYmoKCjcgMCBvYmoKPDwvVHlwZS9DYXRhbG9nL1BhZ2VzIDQgMCBSCi9PcGVuQWN0aW9u
+WzEgMCBSIC9YWVogbnVsbCBudWxsIDBdCi9MYW5nKGVuLUFVKQo+PgplbmRvYmoKCjggMCBvYmoK
+PDwvQ3JlYXRvcjxGRUZGMDA1NzAwNzIwMDY5MDA3NDAwNjUwMDcyPgovUHJvZHVjZXI8RkVGRjAw
+NEMwMDY5MDA2MjAwNzIwMDY1MDA0RjAwNjYwMDY2MDA2OTAwNjMwMDY1MDAyMDAwMzQwMDJFMDAz
+ND4KL0NyZWF0aW9uRGF0ZShEOjIwMTYwMjI2MTMyMzE0KzA4JzAwJyk+PgplbmRvYmoKCnhyZWYK
+MCA5CjAwMDAwMDAwMDAgNjU1MzUgZiAKMDAwMDAwMDIyNiAwMDAwMCBuIAowMDAwMDAwMDE5IDAw
+MDAwIG4gCjAwMDAwMDAxMzIgMDAwMDAgbiAKMDAwMDAwMDM2OCAwMDAwMCBuIAowMDAwMDAwMTUx
+IDAwMDAwIG4gCjAwMDAwMDAxNzMgMDAwMDAgbiAKMDAwMDAwMDQ2NiAwMDAwMCBuIAowMDAwMDAw
+NTYyIDAwMDAwIG4gCnRyYWlsZXIKPDwvU2l6ZSA5L1Jvb3QgNyAwIFIKL0luZm8gOCAwIFIKL0lE
+IFsgPEJDN0REQUQwRDQyOTQ1OTQ2OUU4NzJCMjI1ODUyNkU4Pgo8QkM3RERBRDBENDI5NDU5NDY5
+RTg3MkIyMjU4NTI2RTg+IF0KL0RvY0NoZWNrc3VtIC9BNTYwMEZCMDAzRURCRTg0MTNBNTk3RTZF
+MURDQzJBRgo+PgpzdGFydHhyZWYKNzM2CiUlRU9GCg==
+EOD;
+
     /**
      * This function will take an int or an assignment instance and
      * return an assignment instance. It is just for convenience.
@@ -302,11 +326,7 @@ public static function generate_combined_pdf_for_attempt($assignment, $userid, $
         }
 
         if (!$files) {
-            // This was a blank pdf.
-            $blankpdf = new pdf();
-            $content = $blankpdf->Output(self::COMBINED_PDF_FILENAME, 'S');
-            $file = $fs->create_file_from_string($record, $content);
-            $blankpdf->Close(); // No real need to close this pdf, because it has been outputted, but for clarity.
+            $file = $fs->create_file_from_string($record, base64_decode(self::BLANK_PDF_BASE64));
         } else {
             // This was a combined pdf.
             $file = $fs->create_file_from_pathname($record, $tmpfile);