Skip to content

Script Modules: add dns-prefetch resource hints support#11374

Open
sanketio wants to merge 3 commits intoWordPress:trunkfrom
sanketio:fix/62709
Open

Script Modules: add dns-prefetch resource hints support#11374
sanketio wants to merge 3 commits intoWordPress:trunkfrom
sanketio:fix/62709

Conversation

@sanketio
Copy link
Copy Markdown

@sanketio sanketio commented Mar 27, 2026 •
edited
Loading

Description

wp_resource_hints() prints <link rel="dns-prefetch"> tags for all external hosts used by enqueued scripts and styles, giving browsers an early signal to resolve DNS before requests are made. However, WP_Script_Modules was never wired into this system, so external hosts referenced by script modules received no DNS prefetch hints.

This PR addresses #62709 by adding a new public method WP_Script_Modules::filter_resource_hints(), registered on the wp_resource_hints filter inside add_hooks(). The method collects all enqueued module IDs and their full dependency tree — including dynamic dependencies, which never receive modulepreload hints and are therefore the clearest gap — parses each src for its host, filters out same-site hosts, and appends the external URLs to the dns-prefetch hints array. Deduplication by host is handled downstream by wp_resource_hints() itself, as it does for scripts and styles.

On classic themes, wp_resource_hints fires in wp_head at priority 2, while all module-related tags fire in wp_footer. This means even static dependency hosts will benefit from an early hint in the page <head> well before any module tag is processed.

Changes

  • src/wp-includes/class-wp-script-modules.php

    • Added filter_resource_hints( array $urls, string $relation_type ): array public method.
    • Registered the filter in add_hooks() via wp_resource_hints.

  • tests/phpunit/tests/script-modules/wpScriptModulesResourceHints.php (new file)

    • 9 tests covering: enqueued modules, static dependencies, dynamic dependencies, same-site exclusion, relative-path exclusion, registered-only exclusion, non-dns-prefetch relation types left unmodified, host deduplication, and full wp_resource_hints() integration.

How to test

  1. Enqueue a script module with an external src, e.g.:
wp_enqueue_script_module( 'my-module', 'https://cdn.example.com/module.js' );

  1. View the page source and confirm a <link rel="dns-prefetch" href="https://github.com//cdn.example.com" /> tag appears in <head>.

  2. Run the new unit tests:

phpunit --filter Tests_Script_Modules_WpScriptModules_ResourceHints

Trac ticket: https://core.trac.wordpress.org/ticket/62709

Use of AI Tools

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

@github-actions
Copy link
Copy Markdown

github-actions bot commented Mar 27, 2026

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props sanketparmar.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

@github-actions
Copy link
Copy Markdown

github-actions bot commented Mar 27, 2026

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

  • All changes will be lost when closing a tab with a Playground instance.
  • All changes will be lost when refreshing the page.
  • A fresh instance is created each time the link below is clicked.
  • Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
    it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

1 participant

@sanketio