X-Git-Url: http://source.bookstackapp.com/bookstack/blobdiff_plain/d0fd1b7f5cabcae1809ef98ca9483c90a8899f29..refs/pull/3391/head:/app/Entities/Tools/PageContent.php

diff --git a/app/Entities/Tools/PageContent.php b/app/Entities/Tools/PageContent.php
index 9e2b6a7b6..b1c750adb 100644
--- a/app/Entities/Tools/PageContent.php
+++ b/app/Entities/Tools/PageContent.php
@@ -80,7 +80,7 @@ class PageContent
      */
     protected function extractBase64ImagesFromHtml(string $htmlText): string
     {
-        if (empty($htmlText) || mb_strpos($htmlText, 'data:image') === false) {
+        if (empty($htmlText) || strpos($htmlText, 'data:image') === false) {
             return $htmlText;
         }
 
@@ -109,15 +109,35 @@ class PageContent
 
     /**
      * Convert all inline base64 content to uploaded image files.
+     * Regex is used to locate the start of data-uri definitions then
+     * manual looping over content is done to parse the whole data uri.
+     * Attempting to capture the whole data uri using regex can cause PHP
+     * PCRE limits to be hit with larger, multi-MB, files.
      */
     protected function extractBase64ImagesFromMarkdown(string $markdown)
     {
         $matches = [];
-        preg_match_all('/!\[.*?]\(.*?(data:image\/.*?)[)"\s]/', $markdown, $matches);
+        $contentLength = strlen($markdown);
+        $replacements = [];
+        preg_match_all('/!\[.*?]\(.*?(data:image\/.{1,6};base64,)/', $markdown, $matches, PREG_OFFSET_CAPTURE);
+
+        foreach ($matches[1] as $base64MatchPair) {
+            [$dataUri, $index] = $base64MatchPair;
+
+            for ($i = strlen($dataUri) + $index; $i < $contentLength; $i++) {
+                $char = $markdown[$i];
+                if ($char === ')' || $char === ' ' || $char === "\n" || $char === '"') {
+                    break;
+                }
+                $dataUri .= $char;
+            }
+
+            $newUrl = $this->base64ImageUriToUploadedImageUrl($dataUri);
+            $replacements[] = [$dataUri, $newUrl];
+        }
 
-        foreach ($matches[1] as $base64Match) {
-            $newUrl = $this->base64ImageUriToUploadedImageUrl($base64Match);
-            $markdown = str_replace($base64Match, $newUrl, $markdown);
+        foreach ($replacements as [$dataUri, $newUrl]) {
+            $markdown = str_replace($dataUri, $newUrl, $markdown);
         }
 
         return $markdown;
@@ -219,6 +239,9 @@ class PageContent
             $html .= $doc->saveHTML($childNode);
         }
 
+        // Perform required string-level tweaks
+        $html = str_replace(' ', '&nbsp;', $html);
+
         return $html;
     }