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Troubleshooting Common Code Snippets Errors: Parse Errors, 403 Forbidden, and No Output

24 threads Sep 10, 2025 Plugin → Code snippets

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If you use the Code Snippets plugin to add custom functionality to your WordPress site, you might occasionally run into errors that prevent your snippets from working. Based on common community reports, this guide will help you diagnose and fix the most frequent issues.

1. Parse Errors and Unexpected Tokens

Problem: You see errors like syntax error, unexpected '<', expecting end of file or Parse error: syntax error, unexpected end of snippet.

Why it happens: This often occurs when you try to save HTML or JavaScript code directly into a Functions (PHP) type snippet. The plugin expects valid PHP code, and the PHP parser fails when it encounters HTML tags or JavaScript.

Solution: For any code that is not PHP (like HTML, CSS, or JavaScript), you must use the Content snippet type. Content snippets are designed to output content directly to the front end using a shortcode. If you must use a Functions snippet to output HTML/JS, wrap it in a PHP function and hook it to an appropriate action, like wp_head or wp_footer.

// Correct way to output HTML/JS from a Functions snippet
add_action( 'wp_head', function () {
    echo '<script>console.log("Hello!");</script>';
} );

2. 403 Forbidden Error on Save

Problem: You try to save a snippet and get a 403 Forbidden error.

Why it happens: This is typically a server-level security measure, not a plugin bug. Security software like mod_security, firewalls, or other intrusion detection systems can block a request if the code contains certain character sequences (like <script) that are often associated with injection attacks.

Solution: You have a few options:

  • Modify the Code: Break up the problematic string. For example, change $result = "<script"; to $result = "<"; $result .= "script";.
  • Identify the Security Software: Temporarily disable other security plugins (like Sucuri, Wordfence) to see if the issue persists. If it does, the block is likely at the server level.
  • Contact Your Host: If you suspect a server-level block, contact your hosting provider's support. They can often whitelist the request or adjust the security rules.

3. Snippet Runs but Produces No Output

Problem: You use echo or print_r in your snippet, but nothing appears on the page.

Why it happens: Snippets are loaded early in the WordPress process, similar to plugins. Outputting content at this stage can break the page layout because it sends headers before the actual page content is ready.

Solution: To output content correctly, you must hook your code to a specific WordPress action. The hook you choose determines where the output appears.

// Output text in the footer
add_action( 'wp_footer', function () {
    echo 'This text will appear in the site footer.';
} );

// Output debug information in the admin area
add_filter( 'admin_footer_text', function ( $text ) {
    var_dump( get_users() ); // Debug info
    return $text;
} );

4. General Debugging Tips

  • Check Your Snippet Type: Always double-check that you've selected the correct snippet type (Functions vs. Content) for the code you are using.
  • Use Hooks: For PHP snippets that need to interact with WordPress (which is most of them), always use actions (add_action) or filters (add_filter). The WordPress Hooks documentation is an excellent resource for learning how they work.
  • Test in Staging: Always test new snippets on a staging or development site before using them on your live site to avoid bringing down your production environment.

By understanding these common pitfalls, you can more effectively write and manage your code snippets without encountering frustrating errors.

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