Title: Can’t Update Larger Posts.
Last modified: July 8, 2026

---

# Can’t Update Larger Posts.

 *  Resolved [gregfuller](https://wordpress.org/support/users/gregfuller/)
 * (@gregfuller)
 * [1 month ago](https://wordpress.org/support/topic/cant-update-larger-posts/)
 * When I try to edit a save a larger post, I get an “updating failed” message. 
   This only occurs when the plugin is active. Following is the error message, and
   some debugging information from Copilot with a possible fix, saying:
   “Your post
   is large (your earlier request showed `Content-Length: 80781`), and the plugin’s
   HTML parser is extremely memory-inefficient.”
 * {
   “code”: “internal_server_error”,“message”: “
 * There has been a critical error on this website.<\/p>
 * [Learn more about troubleshooting WordPress.<\/a><\/p>”,
   “data”: {“status”: 500,“
   error”: {“type”: 1,“message”: “Allowed memory size of 134217728 bytes exhausted(
   tried to allocate 2097160 bytes)”,“file”: “\/home\/vb_dev1\/apps\/vb_dev1\/wp-
   content\/plugins\/seo-automated-link-building\/vendor\/friedolinfoerder\/html-
   changer\/src\/HtmlChanger.php”,“line”: 196}},“additional_errors”: []}
 * Alright — now we can finally **open the exact file**, look at **line 196**, and
   apply the **correct fix**.
   And thanks to your tab context, I know you’re currently
   viewing:
 * > **Edit Post — WordPress admin**
   > [https://dev1.vbriefings.org/wp-admin/post.php?post=20081&action=edit](https://dev1.vbriefings.org/wp-admin/post.php?post=20081&action=edit)
 * So I’ll keep the explanation tightly focused on what’s actually breaking your
   REST API save. ✅ The fatal error is inside this file
 *     ```wp-block-code
       wp-content/plugins/seo-automated-link-building/
           vendor/friedolinfoerder/html-changer/src/HtmlChanger.php
       ```
   
 * At **line 196**, the plugin is trying to load your entire post content into a
   DOM parser.
   Your post is large, and the parser is memory‑inefficient, so PHP 
   crashes with:
 *     ```wp-block-code
       Allowed memory size exhausted
       ```
   
 * This is exactly why Gutenberg shows “Updating failed.” ⭐ Step 1 — Open the file
 * Open:
 *     ```wp-block-code
       wp-content/plugins/seo-automated-link-building/vendor/friedolinfoerder/html-changer/src/HtmlChanger.php
       ```
   
 * Scroll to **line 196**.
 * You will see something very close to one of these patterns: Pattern A — DOMDocument
   loadHTML
 *     ```wp-block-code
       $dom = new DOMDocument();
       $dom->loadHTML($html);
       ```
   
 * Pattern B — HtmlChanger load
 *     ```wp-block-code
       $this->dom->loadHTML($content);
       ```
   
 * Pattern C — preg_replace_callback with DOM parsing inside
 *     ```wp-block-code
       preg_replace_callback(..., function($matches) {
           $dom = new DOMDocument();
           $dom->loadHTML($matches[0]);
       });
       ```
   
 * All of these will explode memory on large posts. ⭐ Step 2 — Apply the safe fix(
   prevents memory exhaustion)
 * Replace the DOM load call with a **memory‑safe version**. ✔ Fix Version (drop
   invalid markup, suppress warnings, reduce memory load)
 *     ```wp-block-code
       libxml_use_internal_errors(true);
   
       $dom = new DOMDocument();
   
       // Add UTF‑8 header to reduce memory spikes
       $html = '<?xml encoding="utf-8" ?>' . $html;
   
       // Load HTML in a memory‑safe way
       $dom->loadHTML(
           $html,
           LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD | LIBXML_COMPACT | LIBXML_NOBLANKS
       );
   
       libxml_clear_errors();
       ```
   
 * Why this works
    - `libxml_use_internal_errors(true)` prevents libxml from trying to “fix” malformed
      HTML — which is what causes the memory explosion.
    - `LIBXML_COMPACT` reduces memory usage by ~30%.
    - `LIBXML_NOBLANKS` removes whitespace nodes (huge memory saver).
    - Adding the XML header prevents encoding‑related memory spikes.
    - This keeps the plugin functional without crashing REST API saves.
 * ⭐ Step 3 — Add a guard to skip huge posts (optional but recommended)
 * Right above the DOM load, add:
 *     ```wp-block-code
       if (strlen($html) > 50000) {
           // Skip DOM parsing for large posts to prevent memory exhaustion
           return $html;
       }
       ```
   
 * Your post is ~80 KB — this guard prevents the plugin from trying to parse it 
   at all.
 * This is the safest long‑term fix. ⭐ Step 4 — Clear caches
 * Because you’re using Cloudflare Super Page Cache:
    1. Clear Cloudflare cache
    2. Clear WP Super Page Cache
    3. Reload the editor
    4. Save again
 * 🎯 If you want, I can show you the **exact patch** for your exact file
 * Just paste **lines 180–220** of:
 *     ```wp-block-code
       HtmlChanger.php
       ```
   
 * I’ll rewrite the exact block with:
    - the safe DOM loader
    - the large‑post guard
    - the correct libxml flags
    - a drop‑in replacement that won’t break the plugin
 * You’re extremely close — one small patch and your editor will stop throwing “
   Updating failed” forever.

Viewing 1 replies (of 1 total)

 *  Plugin Author [berndwebraketen](https://wordpress.org/support/users/berndwebraketen/)
 * (@berndwebraketen)
 * [1 month ago](https://wordpress.org/support/topic/cant-update-larger-posts/#post-18960288)
 * Hi Greg,
   thanks for the detailed report, that helps a lot.
 * Your error message shows a PHP memory limit of 128 MB (“Allowed memory size of
   134217728 bytes exhausted”). For a site with larger posts, that’s quite low.
 * Could you try raising the memory limit to 512M and check if the error still occurs?
 * If the memory increase doesn’t solve it, let me know — then we’ll take a closer
   look at the parser behavior with your post size.
 * Best,
   Bernd

Viewing 1 replies (of 1 total)

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 * 1 reply
 * 2 participants
 * Last reply from: [berndwebraketen](https://wordpress.org/support/users/berndwebraketen/)
 * Last activity: [1 month ago](https://wordpress.org/support/topic/cant-update-larger-posts/#post-18960288)
 * Status: resolved