Allow specifying a WordPres/WordPress branch and pulling from GitHub.

packages/playground/website/public/plugin-proxy.php

@@ -334,6 +334,29 @@ function ($curl, $body) use (&$extra_headers_sent, $default_response_headers) {
         }
 
         $downloader->streamFromGithubReleases($_GET['repo'], $_GET['name']);
+    } else if ( isset( $_GET['wordpress-branch'] ) ) {
+        $branch = strtolower( $_GET['wordpress-branch'] );
+        if ( $branch === 'trunk' || $branch === 'master' ) {
+            $branch = 'master';
+            // If the brach is of the form x.x append '-branch' to it.
+        } elseif ( preg_match( '/^\d+\.\d+$/', $branch ) ) {
+            $branch .= '-branch';
+        } elseif ( ! preg_match( '/^\d+\.\d+-branch$/', $branch ) ) {
+            throw new ApiException( 'Invalid branch' );
+        }
+
+        $url = "https://codeload.github.com/WordPress/WordPress/zip/refs/heads/{$branch}";
+
+        streamHttpResponse(
+            $url,
+            'GET',
+            [],
+            file_get_contents('php://input'),
+            null,
+            [
+                'Content-Disposition: attachment; filename="wordpress.zip"',
+            ]
+        );
     } else if (isset($_GET['url'])) {
         // Proxy the current request to $_GET['url'] and return the response,
         // but only if the URL is allowlisted.

packages/playground/wordpress/src/index.ts

@@ -329,12 +329,32 @@ export async function unzipWordPress(php: PHP, wpZip: File) {
 	// @TODO: Don't make so many guesses about the zip file contents. Allow the
 	//        API consumer to specify the exact "coordinates" of WordPress inside
 	//        the zip archive.
-	const wpPath = php.fileExists('/tmp/unzipped-wordpress/wordpress')
+	let wpPath = php.fileExists('/tmp/unzipped-wordpress/wordpress')
 		? '/tmp/unzipped-wordpress/wordpress'
 		: php.fileExists('/tmp/unzipped-wordpress/build')
 		? '/tmp/unzipped-wordpress/build'
 		: '/tmp/unzipped-wordpress';
 
+	// Dive one directory deeper if the zip root does not contain the sample
+	// config file. This is relevant when unzipping a zipped branch from the 
+	// https://github.com/WordPress/WordPress repository.
+	if (!php.fileExists(joinPaths(wpPath, 'wp-config-sample.php'))) {
+		// Still don't know the directory structure of the zip file.
+		// 1. Get the first item in path.
+		const files = php.listFiles(wpPath);
+		if (files.length) {
+			const firstDir = files[0];
+			// 2. If it's a directory that contains wp-config-sample.php, use it.
+			if (
+				php.fileExists(
+					joinPaths(wpPath, firstDir, 'wp-config-sample.php')
+				)
+			) {
+				wpPath = joinPaths(wpPath, firstDir);
+			}
+		}
+	}
+
 	if (
 		php.isDir(php.documentRoot) &&
 		isCleanDirContainingSiteMetadata(php.documentRoot, php)