Offline Mode: Reject external http requests when network is offline

vendor/wp-now/src/network.ts

@@ -0,0 +1,18 @@
+import dns from 'dns';
+/**
+ * Network utility function for checking online status and detecting offline mode
+ */
+
+/**
+ * Check if the system is online by attempting to resolve a known host
+ * @param hostname - The hostname to check (defaults to 'google.com')
+ * @returns Promise<boolean> - true if online, false if offline
+ */
+export async function isOnline(hostname: string = 'google.com'): Promise<boolean> {
+	try {
+		await dns.promises.lookup(hostname);
+		return true;
+	} catch (err) {
+		return false;
+	}
+}

vendor/wp-now/src/start-server.ts

@@ -9,6 +9,7 @@ import { PHP } from '@php-wasm/universal';
 import startWPNow from './wp-now';
 import { output } from './output';
 import { addTrailingSlash } from './add-trailing-slash';
+import { isOnline } from './network';
 
 const requestBodyToBytes = async ( req ): Promise< Uint8Array > =>
 	await new Promise( ( resolve ) => {
@@ -83,6 +84,10 @@ export async function startServer( options: WPNowOptions = {} ): Promise< WPNowS
 				}
 			}
 
+			if ( req.url.startsWith('/wp-admin') && ! await isOnline() ) {
+				requestHeaders['STUDIO_IS_OFFLINE'] = 'true';
+			}
+
 			const data = {
 				url: req.url,
 				headers: requestHeaders,

vendor/wp-now/src/wp-now.ts

@@ -46,6 +46,7 @@ import {
 	getPluginFile,
 	readFileHead,
 } from './wp-playground-wordpress';
+import { isOnline } from './network';
 
 export default async function startWPNow(
 	options: Partial< WPNowOptions > = {}
@@ -583,6 +584,23 @@ async function mountInternalMuPlugins( php: PHP, options: WPNowOptions ) {
 		);
 	}
 
+	php.writeFile(
+		path.posix.join( PLAYGROUND_INTERNAL_MU_PLUGINS_FOLDER, '0-block-offline-external-request.php' ),
+		`<?php
+		add_filter( 'pre_http_request', function( $preempt, $parsed_args, $url ) {
+			if ( isset( $_SERVER['HTTP_STUDIO_IS_OFFLINE'] ) ) {
+				$parsed_url = parse_url( $url );
+				$host = isset( $parsed_url['host'] ) ? $parsed_url['host'] : $url;
+				return new WP_Error(
+					'request_failed',
+					sprintf( __( 'Could not resolve host: %s' ), $host )
+				);
+			}
+			return $preempt;
+		}, 10, 3 );
+		`
+	);
+
 	php.writeFile(
 		path.posix.join( PLAYGROUND_INTERNAL_MU_PLUGINS_FOLDER, '0-http-request-timeout.php' ),
 		`<?php
@@ -676,9 +694,16 @@ async function installationSteps( php: PHP, options: WPNowOptions ) {
 	const siteLanguage = options.siteLanguage;
 
 	const executeStep = async ( step: 0 | 1 | 2 ) => {
+		const requestHeaders = {};
+
+		if ( ! await isOnline() ) {
+			requestHeaders['STUDIO_IS_OFFLINE'] = 'true';
+		}
+
 		return php.requestHandler.request( {
 			url: `/wp-admin/install.php?step=${ step }`,
 			method: 'POST',
+			headers: requestHeaders,
 			body:
 				step === 2
 					? {
@@ -695,6 +720,7 @@ async function installationSteps( php: PHP, options: WPNowOptions ) {
 					: {
 							language: siteLanguage,
 					  },
+
 		} );
 	};
 	// First two steps are needed to download and set translations