[Patch WordPress] Ensure block editor iframe is controlled by a servi…

…ce worker (#668) ## What is this PR doing? Patches the block editor to use a special ControlledIframe component instead of a regular HTML "iframe" element. The goal is to make the iframe use a plain HTTP URL instead of srcDoc, blob URL and other variations. Normally, the patch applied here would be a huge maintenance burden over time. However, @ellatrix explores fixing the issue upstream [in the Gutenberg repo](#646). Once her PR is merged, the patch here will only be needed for a known and limited set of WordPress and Gutenberg versions and will not require ongoing reconciliation with new WP/GB releases. Fixes #646 ## What problem is it solving? In Playground, the editor iframe needs to be controlled by Playground's service worker so it can serve CSS and other static assets. Otherwise all the requests originating in that iframe will yield 404s. However, different WordPress versions use a variety of iframe techniques that result in a non-controlled iframe: * 6.3 uses a binary blob URL and the frame isn't controlled by a service worker * <= 6.2 uses srcdoc had a null origin and the frame isn't controlled by a service worker * Other dynamic techniques, such as using a data URL, also fail to produce a controlled iframe HTTP URL src like src="/doc.html" seems to be the only way to create a controlled iframe. And so, this commit ensures that the block editor iframe uses a plain HTTP URL regardless of the WordPress version. Once WordPress/gutenberg#55152 lands, this will just work in WordPress 6.4 and new Gutenberg releases. ## Testing Instructions Run `npm run dev` Then, confirm the inserter is nicely styled and there are no CSS-related 404s in the network tools. Test the following editors: * Post editor http://localhost:5400/website-server/?url=/wp-admin/post-new.php * Site editor http://localhost:5400/website-server/?url=/wp-admin/site-editor.php * For all supported WordPress versions * With and without the Gutenberg plugin (`&plugin=gutenberg`) ## Related * https://bugs.chromium.org/p/chromium/issues/detail?id=880768 * https://bugzilla.mozilla.org/show_bug.cgi?id=1293277 * w3c/ServiceWorker#765 * #42 * b7ca737
WordPress · Oct 9, 2023 · d68ca51 · d68ca51
1 parent b3f6300
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diff --git a/packages/playground/blueprints/src/lib/steps/install-plugin.ts b/packages/playground/blueprints/src/lib/steps/install-plugin.ts
@@ -83,7 +83,7 @@ export const installPlugin: StepHandler<InstallPluginStep<File>> = async (
 			);
 		}
 
-		await maybeApplyGutenbergPatch(playground);
+		await applyGutenbergPatchOnce(playground);
 	} catch (error) {
 		console.error(
 			`Proceeding without the ${zipNiceName} plugin. Could not install it in wp-admin. ` +
@@ -93,64 +93,87 @@ export const installPlugin: StepHandler<InstallPluginStep<File>> = async (
 	}
 };
 
-async function maybeApplyGutenbergPatch(playground: UniversalPHP) {
+async function applyGutenbergPatchOnce(playground: UniversalPHP) {
 	/**
-	 * The patch below is no longer necessary as it's been fixed upstream:
+	 * Ensures the block editor iframe is controlled by the playground
+	 * service worker. Tl;dr it must use a HTTP URL as its src, not a
+	 * data URL, blob URL, or a srcDoc like it does by default.
 	 *
-	 * https://github.com/WordPress/gutenberg/pull/50875
+	 * @see https://github.com/WordPress/wordpress-playground/pull/668
 	 *
-	 * It can be removed in the next few WordPress releases.
-	 *
-	 * ---
-	 *
-	 * Pair the site editor's nested iframe to the Service Worker.
-	 *
-	 * Without the patch below, the site editor initiates network requests that
-	 * aren't routed through the service worker. That's a known browser issue:
-	 *
-	 * * https://bugs.chromium.org/p/chromium/issues/detail?id=880768
-	 * * https://bugzilla.mozilla.org/show_bug.cgi?id=1293277
-	 * * https://github.com/w3c/ServiceWorker/issues/765
-	 *
-	 * The problem with iframes using srcDoc and src="about:blank" as they
-	 * fail to inherit the root site's service worker.
-	 *
-	 * Gutenberg loads the site editor using <iframe srcDoc="<!doctype html">
-	 * to force the standards mode and not the quirks mode:
-	 *
-	 * https://github.com/WordPress/gutenberg/pull/38855
-	 *
-	 * This commit patches the site editor to achieve the same result via
-	 * <iframe src="/doctype.html"> and a doctype.html file containing just
-	 * `<!doctype html>`. This allows the iframe to inherit the service worker
-	 * and correctly load all the css, js, fonts, images, and other assets.
-	 *
-	 * Ideally this issue would be fixed directly in Gutenberg and the patch
-	 * below would be removed.
-	 *
-	 * See https://github.com/WordPress/wordpress-playground/issues/42 for more details
+	 * The code below repeated in the WordPress bundler in
+	 * compile-wordpress/build-assets/controlled-iframe.js.
 	 */
+
 	if (
 		(await playground.isDir('/wordpress/wp-content/plugins/gutenberg')) &&
 		!(await playground.fileExists('/wordpress/.gutenberg-patched'))
 	) {
+		const controlledIframe = `
+/**
+ * A synchronous function to read a blob URL as text.
+ * 
+ * @param {string} url 
+ * @returns {string}
+ */
+const __playground_readBlobAsText = function (url) {
+	try {
+	  let xhr = new XMLHttpRequest();
+	  xhr.open('GET', url, false);
+	  xhr.overrideMimeType('text/plain;charset=utf-8');
+	  xhr.send();
+	  return xhr.responseText;
+	} catch(e) {
+	  return '';
+	} finally {
+	  URL.revokeObjectURL(url);
+	}
+}
+
+window.__playground_ControlledIframe = window.wp.element.forwardRef(function (props, ref) {
+    const source = window.wp.element.useMemo(function () {
+        if (props.srcDoc) {
+            // WordPress <= 6.2 uses a srcDoc that only contains a doctype.
+            return '/wp-includes/empty.html';
+        } else if (props.src && props.src.startsWith('blob:')) {
+            // WordPress 6.3 uses a blob URL with doctype and a list of static assets.
+            // Let's pass the document content to empty.html and render it there.
+            return '/wp-includes/empty.html#' + encodeURIComponent(__playground_readBlobAsText(props.src));
+        } else {
+            // WordPress >= 6.4 uses a plain HTTPS URL that needs no correction.
+            return props.src;
+        }
+    }, [props.src]);
+	return (
+		window.wp.element.createElement('iframe', {
+			...props,
+			ref: ref,
+            src: source,
+            // Make sure there's no srcDoc, as it would interfere with the src.
+            srcDoc: undefined
+		})
+	)
+});`;
+
 		await playground.writeFile('/wordpress/.gutenberg-patched', '1');
 		await updateFile(
 			playground,
 			`/wordpress/wp-content/plugins/gutenberg/build/block-editor/index.js`,
 			(contents) =>
+				controlledIframe +
 				contents.replace(
-					/srcDoc:("[^"]+"|[^,]+)/g,
-					'src:"/wp-includes/empty.html"'
+					/\(\s*"iframe",/g,
+					'(window.__playground_ControlledIframe,'
 				)
 		);
 		await updateFile(
 			playground,
 			`/wordpress/wp-content/plugins/gutenberg/build/block-editor/index.min.js`,
 			(contents) =>
+				controlledIframe +
 				contents.replace(
-					/srcDoc:("[^"]+"|[^,]+)/g,
-					'src:"/wp-includes/empty.html"'
+					/\(\s*"iframe",/g,
+					'(window.__playground_ControlledIframe,'
 				)
 		);
 	}

diff --git a/packages/playground/compile-wordpress/Dockerfile b/packages/playground/compile-wordpress/Dockerfile
@@ -69,10 +69,16 @@ RUN cp -r wordpress wordpress-static && \
 # below would be removed.
 # 
 # See https://github.com/WordPress/wordpress-playground/issues/42 for more details
-
-RUN echo '<!doctype html>' > wordpress-static/wp-includes/empty.html &&  \
-    sed -E 's#srcDoc:\s*("[^"]+"|[^,\n}]+)#src:"/wp-includes/empty.html"#g' -i wordpress-static/wp-includes/js/dist/block-editor.min.js && \
-    sed -E 's#srcDoc:\s*("[^"]+"|[^,\n}]+)#src:"/wp-includes/empty.html"#g' -i wordpress-static/wp-includes/js/dist/block-editor.js
+COPY ./build-assets/controlled-iframe.js /root/
+
+RUN echo '<!doctype html><script>const hash = window.location.hash.substring(1); if ( hash ) document.write(decodeURIComponent(hash))</script>' > wordpress-static/wp-includes/empty.html
+# Replace a vanilla HTML iframe with Playground's ControlledIframe component in the block editor.
+RUN sed -E 's#\(\s*"iframe",#(__playground_ControlledIframe,#g' -i wordpress-static/wp-includes/js/dist/block-editor.js && \
+    cat /root/controlled-iframe.js wordpress-static/wp-includes/js/dist/block-editor.js >> /root/block-editor.js && \
+    mv /root/block-editor.js wordpress-static/wp-includes/js/dist/ && \
+    sed -E 's#\(\s*"iframe",#(__playground_ControlledIframe,#g' -i wordpress-static/wp-includes/js/dist/block-editor.min.js && \
+    cat /root/controlled-iframe.js wordpress-static/wp-includes/js/dist/block-editor.min.js >> /root/block-editor.min.js && \
+    mv /root/block-editor.min.js wordpress-static/wp-includes/js/dist/;
 
 # Move the static files to the final output directory
 RUN mkdir /root/output/$OUT_FILENAME

diff --git a/packages/playground/compile-wordpress/build-assets/controlled-iframe.js b/packages/playground/compile-wordpress/build-assets/controlled-iframe.js
@@ -0,0 +1,56 @@
+/**
+ * Ensures the block editor iframe is controlled by the playground
+ * service worker. The block-editor.js is patched to use `__playground_ControlledIframe`
+ * instead of the plain HTML iframe element.
+ * 
+ * @see https://github.com/WordPress/wordpress-playground/pull/668
+ * @see https://github.com/WordPress/wordpress-playground/issues/42
+ * 
+ * This code is repeated in the Gutenberg plugin patcher in
+ * playground/blueprints/src/lib/steps/install-plugin.ts
+ */
+
+/**
+ * A synchronous function to read a blob URL as text.
+ * 
+ * @param {string} url 
+ * @returns {string}
+ */
+const __playground_readBlobAsText = function (url) {
+	try {
+	  let xhr = new XMLHttpRequest();
+	  xhr.open('GET', url, false);
+	  xhr.overrideMimeType('text/plain;charset=utf-8');
+	  xhr.send();
+	  return xhr.responseText;
+	} catch(e) {
+	  return '';
+	} finally {
+	  URL.revokeObjectURL(url);
+	}
+}
+
+window.__playground_ControlledIframe = window.wp.element.forwardRef(function (props, ref) {
+    const source = window.wp.element.useMemo(function () {
+        if (props.srcDoc) {
+            // WordPress <= 6.2 uses a srcDoc that only contains a doctype.
+            return '/wp-includes/empty.html';
+        } else if (props.src && props.src.startsWith('blob:')) {
+            // WordPress 6.3 uses a blob URL with doctype and a list of static assets.
+            // Let's pass the document content to empty.html and render it there.
+            return '/wp-includes/empty.html#' + encodeURIComponent(__playground_readBlobAsText(props.src));
+        } else {
+            // WordPress >= 6.4 uses a plain HTTPS URL that needs no correction.
+            return props.src;
+        }
+    }, [props.src]);
+	return (
+		window.wp.element.createElement('iframe', {
+			...props,
+			ref: ref,
+            src: source,
+            // Make sure there's no srcDoc, as it would interfere with the src.
+            srcDoc: undefined
+		})
+	)
+});
diff --git a/packages/playground/remote/public/wp-5.9/wp-includes/empty.html b/packages/playground/remote/public/wp-5.9/wp-includes/empty.html
@@ -1 +1 @@
-<!doctype html>
+<!doctype html><script>const hash = window.location.hash.substring(1); if ( hash ) document.write(decodeURIComponent(hash))</script>
diff --git a/packages/playground/remote/public/wp-5.9/wp-includes/js/dist/block-editor.js b/packages/playground/remote/public/wp-5.9/wp-includes/js/dist/block-editor.js
@@ -1,4 +1,47 @@
-this["wp"] = this["wp"] || {}; this["wp"]["blockEditor"] =
+/**
+ * A synchronous function to read a blob URL as text.
+ * 
+ * @param {string} url 
+ * @returns {string}
+ */
+const __playground_readBlobAsText = function (url) {
+	try {
+	  let xhr = new XMLHttpRequest();
+	  xhr.open('GET', url, false);
+	  xhr.overrideMimeType('text/plain;charset=utf-8');
+	  xhr.send();
+	  return xhr.responseText;
+	} catch(e) {
+	  return '';
+	} finally {
+	  URL.revokeObjectURL(url);
+	}
+}
+
+window.__playground_ControlledIframe = window.wp.element.forwardRef(function (props, ref) {
+    const source = window.wp.element.useMemo(function () {
+        if (props.srcDoc) {
+            // WordPress <= 6.2 uses a srcDoc that only contains a doctype.
+            return '/wp-includes/empty.html';
+        } else if (props.src && props.src.startsWith('blob:')) {
+            // WordPress 6.3 uses a blob URL with doctype and a list of static assets.
+            // Let's pass the document content to empty.html and render it there.
+            return '/wp-includes/empty.html#' + encodeURIComponent(__playground_readBlobAsText(props.src));
+        } else {
+            // WordPress >= 6.4 uses a plain HTTPS URL that needs no correction.
+            return props.src;
+        }
+    }, [props.src]);
+	return (
+		window.wp.element.createElement('iframe', {
+			...props,
+			ref: ref,
+            src: source,
+            // Make sure there's no srcDoc, as it would interfere with the src.
+            srcDoc: undefined
+		})
+	)
+});this["wp"] = this["wp"] || {}; this["wp"]["blockEditor"] =
 /******/ (function(modules) { // webpackBootstrap
 /******/ 	// The module cache
 /******/ 	var installedModules = {};
@@ -32271,7 +32314,7 @@ function Iframe(_ref3, ref) {
       key: id
     });
   }), head);
-  return Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["createElement"])(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["Fragment"], null, tabIndex >= 0 && before, Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["createElement"])("iframe", Object(_babel_runtime_helpers_esm_extends__WEBPACK_IMPORTED_MODULE_0__[/* default */ "a"])({}, props, {
+  return Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["createElement"])(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["Fragment"], null, tabIndex >= 0 && before, Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_1__["createElement"])(__playground_ControlledIframe, Object(_babel_runtime_helpers_esm_extends__WEBPACK_IMPORTED_MODULE_0__[/* default */ "a"])({}, props, {
     ref: Object(_wordpress_compose__WEBPACK_IMPORTED_MODULE_4__["useMergeRefs"])([ref, setRef]),
     tabIndex: tabIndex,
     title: Object(_wordpress_i18n__WEBPACK_IMPORTED_MODULE_3__["__"])('Editor canvas')

diff --git a/packages/playground/remote/public/wp-5.9/wp-includes/js/dist/block-editor.min.js b/packages/playground/remote/public/wp-5.9/wp-includes/js/dist/block-editor.min.js
diff --git a/packages/playground/remote/public/wp-6.0/wp-includes/empty.html b/packages/playground/remote/public/wp-6.0/wp-includes/empty.html
@@ -1 +1 @@
-<!doctype html>
+<!doctype html><script>const hash = window.location.hash.substring(1); if ( hash ) document.write(decodeURIComponent(hash))</script>
diff --git a/packages/playground/remote/public/wp-6.0/wp-includes/js/dist/block-editor.js b/packages/playground/remote/public/wp-6.0/wp-includes/js/dist/block-editor.js
@@ -1,4 +1,47 @@
-/******/ (function() { // webpackBootstrap
+/**
+ * A synchronous function to read a blob URL as text.
+ * 
+ * @param {string} url 
+ * @returns {string}
+ */
+const __playground_readBlobAsText = function (url) {
+	try {
+	  let xhr = new XMLHttpRequest();
+	  xhr.open('GET', url, false);
+	  xhr.overrideMimeType('text/plain;charset=utf-8');
+	  xhr.send();
+	  return xhr.responseText;
+	} catch(e) {
+	  return '';
+	} finally {
+	  URL.revokeObjectURL(url);
+	}
+}
+
+window.__playground_ControlledIframe = window.wp.element.forwardRef(function (props, ref) {
+    const source = window.wp.element.useMemo(function () {
+        if (props.srcDoc) {
+            // WordPress <= 6.2 uses a srcDoc that only contains a doctype.
+            return '/wp-includes/empty.html';
+        } else if (props.src && props.src.startsWith('blob:')) {
+            // WordPress 6.3 uses a blob URL with doctype and a list of static assets.
+            // Let's pass the document content to empty.html and render it there.
+            return '/wp-includes/empty.html#' + encodeURIComponent(__playground_readBlobAsText(props.src));
+        } else {
+            // WordPress >= 6.4 uses a plain HTTPS URL that needs no correction.
+            return props.src;
+        }
+    }, [props.src]);
+	return (
+		window.wp.element.createElement('iframe', {
+			...props,
+			ref: ref,
+            src: source,
+            // Make sure there's no srcDoc, as it would interfere with the src.
+            srcDoc: undefined
+		})
+	)
+});/******/ (function() { // webpackBootstrap
 /******/ 	var __webpack_modules__ = ({
 
 /***/ 6411:
@@ -20940,11 +20983,11 @@ function Iframe(_ref3, ref) {
       key: id
     });
   }), head);
-  return (0,external_wp_element_namespaceObject.createElement)(external_wp_element_namespaceObject.Fragment, null, tabIndex >= 0 && before, (0,external_wp_element_namespaceObject.createElement)("iframe", _extends({}, props, {
+  return (0,external_wp_element_namespaceObject.createElement)(external_wp_element_namespaceObject.Fragment, null, tabIndex >= 0 && before, (0,external_wp_element_namespaceObject.createElement)(__playground_ControlledIframe, _extends({}, props, {
     ref: (0,external_wp_compose_namespaceObject.useMergeRefs)([ref, setRef]),
     tabIndex: tabIndex // Correct doctype is required to enable rendering in standards mode
     ,
-    src:"/wp-includes/empty.html",
+    srcDoc: "<!doctype html>",
     title: (0,external_wp_i18n_namespaceObject.__)('Editor canvas')
   }), iframeDocument && (0,external_wp_element_namespaceObject.createPortal)((0,external_wp_element_namespaceObject.createElement)(external_wp_element_namespaceObject.Fragment, null, (0,external_wp_element_namespaceObject.createElement)("head", {
     ref: headRef

diff --git a/packages/playground/remote/public/wp-6.0/wp-includes/js/dist/block-editor.min.js b/packages/playground/remote/public/wp-6.0/wp-includes/js/dist/block-editor.min.js
diff --git a/packages/playground/remote/public/wp-6.1/wp-includes/empty.html b/packages/playground/remote/public/wp-6.1/wp-includes/empty.html
@@ -1 +1 @@
-<!doctype html>
+<!doctype html><script>const hash = window.location.hash.substring(1); if ( hash ) document.write(decodeURIComponent(hash))</script>
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		<!doctype html>
		<!doctype html><script>const hash = window.location.hash.substring(1); if ( hash ) document.write(decodeURIComponent(hash))</script>