Document: add MathJax script in all HTML document before returning the document for download - refs BT#21424

main/inc/lib/document.lib.php

@@ -427,6 +427,7 @@ class DocumentManager
 
             switch ($contentType) {
                 case 'text/html':
+                    $enableMathJaxScript = api_get_setting('enabled_mathjax');
                     if (isset($lpFixedEncoding) && $lpFixedEncoding === 'true') {
                         $contentType .= '; charset=UTF-8';
                     } else {
@@ -480,15 +481,23 @@ class DocumentManager
                     ['https%3A%2F%2F', 'https://'],
                     $content
                 );
+                if ($enableMathJaxScript) {
+                    $content = self::includeMathJaxScript($content);
+                }
                 echo $content;
             } else {
-                if (function_exists('ob_end_clean') && ob_get_length()) {
-                    // Use ob_end_clean() to avoid weird buffering situations
-                    // where file is sent broken/incomplete for download
-                    ob_end_clean();
+                if ($enableMathJaxScript) {
+                    $content = file_get_contents($full_file_name);
+                    $content = self::includeMathJaxScript($content);
+                    echo $content;
+                } else {
+                    if (function_exists('ob_end_clean') && ob_get_length()) {
+                        // Use ob_end_clean() to avoid weird buffering situations
+                        // where file is sent broken/incomplete for download
+                        ob_end_clean();
+                    }
+                    readfile($full_file_name);
                 }
-
-                readfile($full_file_name);
             }
 
             return true;
@@ -7516,4 +7525,26 @@ class DocumentManager
 
         return $btn;
     }
+
+    /**
+     * Include MathJax script in document.
+     *
+     * @param string file content $content
+     *
+     * @return string file content
+     */
+    private static function includeMathJaxScript($content)
+    {
+        $scriptTag = '<script src="'.api_get_path(WEB_PUBLIC_PATH).'assets/MathJax/MathJax.js?config=TeX-MML-AM_HTMLorMML"></script>';
+        // Find position of </body> tag
+        $pos = strpos($content, '</body>');
+        // If </body> tag found, insert the script tag before it
+        if ($pos !== false) {
+            $content = substr_replace($content, $scriptTag, $pos, 0);
+        } else {
+            // If </body> tag not found, just append the script tag at the end
+            $content .= $scriptTag;
+        }
+        return $content;
+    }
 }