[Website] Carry external embed origins into framing policies by adamziel · Pull Request #4480 · WordPress/wordpress-playground

adamziel · 2026-10-21T11:41:01Z

Keep external Playground embeds working while preventing WordPress pages from embedding the trusted Playground app or API.

What must keep working

A lesson on another website can embed Playground:

learn.example
└── playground.wordpress.net
    └── playground.wordpress.net/remote.html

But WordPress code must not be able to create this frame:

wp.playground.wordpress.net
└── playground.wordpress.net/api.html

The second case matters because api.html exposes Playground operations. WordPress must not be able to load a fresh copy and connect to it as its parent.

How the browser blocks it

Build a response header such as:

Content-Security-Policy: frame-ancestors 'self' https://learn.example

This tells the browser to allow that page inside frames from the Playground origin or learn.example. The browser checks every enclosing frame, not just the immediate parent. Putting another website between WordPress and Playground therefore does not hide WordPress from the check. See the browser rule.

The app needs to know which external origins to include. This PR gathers them from:

The referrer, which normally identifies the page loading the iframe.
Repeated embedder-origin URL parameters, used when the referrer is missing or there are additional outer frames.

The SDK adds the origins it can determine and carries existing declarations into its inner iframe URLs. This includes about:blank callers that inherit an origin even though their URL does not name it. A nested SDK caller can also pass along its referrer as an outer frame. A top-level caller must not: its referrer names the previous page, not a frame enclosing Playground.

A plain iframe that hides its referrer must supply embedder-origin itself. Nested external embeds must declare every external origin; the SDK cannot discover arbitrary hidden outer frames.

Why declarations cannot let WordPress through

The policy builder always removes the configured WordPress hostname, including values using another port or HTTP instead of HTTPS. Invalid values and wildcard declarations are also discarded.

Declaring an innocent website instead does not help. The browser checks the real frame chain, sees the WordPress origin missing from the allowed list, and blocks the trusted page.

These parameters control whether a page may be embedded. They do not change API permissions or storage rules.

Scope

This PR adds SDK propagation, the header-building function, and unit tests. It does not attach the header to responses yet. #4482 applies it to app HTML returned by the service worker, #4483 adds the local server headers, and #4468 adds the staging server headers.

My WordPress development reloads

The local dev server serves the app shell when reloading a WordPress directory URL such as /my-apps/. The service worker forwards that request with Sec-Fetch-Dest: empty, so the server checks the HTML Accept header instead. Scoped WordPress requests and runtime files still go through the remote server proxy. This changes development routing only.

Testing

Check that SDK-created iframe URLs carry the external caller's origin, including with a hidden referrer. With the later server layer installed, embed Playground from an external page and confirm it loads. Repeat from the WordPress iframe, including through an intermediate external frame, and confirm the trusted app/API page cannot load there.

In local My WordPress, open a second tab, retire the shared runtime, and choose Reload this tab in the old tab. Confirm that the app loads again and saved data remains.

Summary by CodeRabbit

New Features
- Added a WordPress popup experience for opening Adminer and phpMyAdmin tools while preserving scoped paths, query parameters, and fragments.
- Improved embedded Playground support by preserving valid frame ancestry and embedder origins across nested frames.
- Added secure frame-ancestor handling and configurable third-party framing support.
Bug Fixes
- Fixed database-tool popups and WordPress reloads in development environments.
- Improved validation to reject unsafe or invalid embedding origins.

coderabbitai · 2026-10-21T11:41:09Z

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packages/playground/personal-wp/playwright/e2e/shared-runtime.spec.ts

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📝 Walkthrough

The client propagates embedding origins through iframe URLs. Remote code filters those origins for CSP. WordPress popup entries route cross-origin database tools through scoped iframes. Development proxy and reload tests cover related navigation behavior.

Changes: Embedder origin policy

Layer / File(s)	Summary
Propagate embedding origins `packages/playground/client/src/index.ts`, `packages/playground/client/src/index.spec.ts`	`loadIframe` adds eligible origins from the target, parent, document, and referrer. Tests cover top-level, nested, and `about:blank` callers.
Build the frame-ancestors policy `packages/playground/remote/src/lib/frame-ancestors.ts`, `packages/playground/remote/src/lib/frame-ancestors.spec.ts`	`getFrameAncestors` filters URL and referrer origins, excludes disallowed values, and returns a deduplicated CSP directive beginning with `'self'`.
Route database tools through WordPress popups `packages/playground/remote/wordpress-popup.html`, `packages/playground/remote/src/lib/wordpress-popup.ts`, `packages/playground/remote/vite.config.ts`, `packages/playground/website/src/lib/wordpress-popup.ts`, `packages/playground/website/src/components/site-manager/site-database-panel/*`, `packages/playground/website/playwright/e2e/website-ui.spec.ts`, `packages/playground/tools/src/phpmyadmin/config.inc.php`	The build adds a WordPress popup entry. Cross-origin tool URLs use the popup and preserve scoped routing data. End-to-end tests resolve nested popup frames, and phpMyAdmin enables third-party framing only when configured.
Route development documents and verify reloads `packages/playground/personal-wp/vite.config.ts`, `packages/playground/personal-wp/playwright/e2e/shared-runtime.spec.ts`	The development proxy routes non-scoped directory HTML through the website entry point. The reload test verifies a successful final navigation response.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant Website
  participant WordPressPopup
  participant DatabaseTool
  Website->>WordPressPopup: Open rewritten cross-origin tool URL
  WordPressPopup->>WordPressPopup: Validate scoped destination
  WordPressPopup->>DatabaseTool: Load destination in the wp iframe
  DatabaseTool-->>Website: Expose the tool document through the popup frame

Suggested reviewers: akirk, brandonpayton

Merge Risk: ⚪ Minimal · up to e423a

No actionable merge-blocking risk is established in the available evidence.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly identifies the main change: carrying external embed origins into framing policies. It is concise and directly related to the implementation and objectives.
Docstring Coverage		Docstring coverage is 81.82% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 11 functions across 14 files.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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Inline comments:
Review comments at @packages/playground/client/src/index.ts:
- Around line 310-312: Update the origin collection around document.referrer to
add the referrer origin only when document.defaultView exists and represents a
nested frame (defaultView.parent differs from defaultView); preserve the
existing empty-referrer guard. Adjust the related iframe mock so its
ownerDocument includes a nested-frame defaultView.

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packages/playground/client/src/index.spec.ts
packages/playground/client/src/index.ts
packages/playground/remote/src/lib/frame-ancestors.spec.ts
packages/playground/remote/src/lib/frame-ancestors.ts

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Part 4/10. Builds on #4478 · Next: #4480. Keeps “Open Adminer” and “Open phpMyAdmin” connected to the running Playground after WordPress moves to a separate origin. ## Why opening the tool directly can break For example, the running Playground has this layout: ```text playground.wordpress.net ← browser tab └── wp.playground.wordpress.net ← WordPress iframe ``` WordPress runs in the browser, not on our web server. Its HTTP requests must reach the service worker that connects them to the running PHP instance. Opening Adminer directly would make the WordPress origin the top-level page: ```text wp.playground.wordpress.net/scope:abc/adminer/ ← new tab ``` WebKit can look up service workers using both the top-level origin and the WordPress origin. The new tab has changed the first value, so it can miss the worker serving the existing site. This is browser separation called *partitioning*. [WebKit describes the rule here.](https://webkit.org/blog/8090/workers-at-your-service/) ## What this changes Open a small page on the Playground origin and put the database tool inside its WordPress iframe: ```text playground.wordpress.net/wordpress-popup.html ← new tab └── wp.playground.wordpress.net/scope:abc/adminer/ ``` Both origins now match the running Playground. The tool can use its existing service worker, PHP instance, and database. The wrapper is just a full-window iframe. It does not boot another Playground or copy the database. - Use the wrapper only when WordPress and remote.html have different origins. Same-origin setups keep their direct URLs. - Accept only URLs on the configured WordPress origin with a `/scope:…/` path. - Disable phpMyAdmin's attempt to escape its iframe for the split-origin setup. - Keep WordPress code on the WordPress origin. The surrounding app-origin page does not grant it direct access to the app's OPFS. Not every browser needs the wrapper: Chrome can share the service-worker partition for same-site origins. Keeping the frame layout also covers browsers that separate it by the full top-level origin. [Chrome's partition rules](https://privacysandbox.google.com/cookies/storage-partitioning). ## Testing With WordPress on a separate origin, open Adminer and phpMyAdmin from the database panel. In each tool, browse a table, save a change, and confirm it appears in the running WordPress site. Repeat with a same-origin setup to check the direct tabs still work.   ## Summary by CodeRabbit * **New Features** * Added support for opening Adminer and phpMyAdmin in dedicated WordPress popup pages. * Preserved destination paths, query parameters, and fragments when opening external WordPress tools. * Added a full-screen, sandboxed popup experience for embedded WordPress pages. * Improved cross-origin framing safeguards for database management tools. * **Bug Fixes** * Improved popup loading and navigation behavior for database tools, including iframe-based popups.

adamziel · 2026-10-21T20:22:55Z

Dropping this approach because existing Playground embeds must keep working without changes, including plain iframes and older SDK integrations that send no referrer. Once enforced, this policy would block those embeds unless they supplied the new embedder-origin parameter. The later PRs still need to remove or replace the matching policy before shipping; closing this PR does not remove it from their branches. The separate WordPress origin remains useful, but the path through a newly embedded trusted app/API document still needs a compatible security solution.

github-actions Bot added [Aspect] Browser [Package][@wp-playground] Remote [Package][@wp-playground] Client labels Oct 21, 2026

This was referenced Oct 21, 2026

[Website] Keep database tools in the app browser partition #4479

Merged

[Web] Keep editor canvas isolation when DIP and COEP overlap #4481

Merged

adamziel added 3 commits October 21, 2026 19:35

[Website] Keep database tools in the app browser partition

6a6dbfa

[Website] Explain how popup frames reuse the running service worker

8a9458f

[Website] Carry external embed origins into framing policies

91e9992

adamziel force-pushed the codex/frame-review-04-database-popups branch from c5f7f59 to 8a9458f Compare October 21, 2026 17:39

adamziel force-pushed the codex/frame-review-05-embed-origins branch from e34505d to 91e9992 Compare October 21, 2026 17:39

adamziel added this pull request to stack #4489 October 21, 2026 17:39

coderabbitai Bot reviewed Oct 21, 2026

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Comment thread packages/playground/client/src/index.ts Outdated

Base automatically changed from codex/frame-review-04-database-popups to trunk October 21, 2026 17:50

This was referenced Oct 21, 2026

[Website] Serve WordPress frames from a separate internal origin #4482

Merged

[Website] Run local subdomains with storage and API boundary checks #4483

Merged

adamziel added 2 commits October 21, 2026 20:26

[Web] Limit declared referrers to enclosing frames

2d38668

[Website] Serve the app shell on My WordPress directory reloads

724a6a2

github-actions Bot added [Aspect] Website [Package][@wp-playground] Website labels Oct 21, 2026

[Personal WP] Check the final document response after reload redirects

e423a27

adamziel closed this Oct 21, 2026

adamziel removed this pull request from stack #4489 October 21, 2026 20:37

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[Website] Carry external embed origins into framing policies - #4480

[Website] Carry external embed origins into framing policies#4480
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What must keep working

How the browser blocks it

Why declarations cannot let WordPress through

Scope

My WordPress development reloads

Testing

Summary by CodeRabbit

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