Explore: Setup SQLite database integration without creating wp-conten…

…t/db.php (#1382) Related to #1379 Loads the SQLite database integration without creating a drop-in `wp-content/db.php` plugin. Instead, it leans on the `auto_prepend_file` PHP option to provide a fake global `$wpdb` variable. This prevents WordPress from trying to connect to MySQL. The first time that `$wpdb` is used for reading or a method call, it loads the actual SQLite database integration. ## Follow-up work Use the same SQLite setup method in the web version of Playground. This could happen either when a non-minified WordPress build is used or, for simplicity, always if we remove the SQLite integration plugin from the minified build. ## Testing instructions Run `bun packages/playground/cli/src/cli.ts server --login` and confirm the server starts without any database errors. Test coverage coming as a part of the larger boot protocol discussion, see #1379.
WordPress · May 14, 2024 · 0b05edf · 0b05edf
1 parent 7531696
commit 0b05edf
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Showing 4 changed files with 121 additions and 39 deletions.
diff --git a/packages/playground/cli/src/setup-wp.ts b/packages/playground/cli/src/setup-wp.ts
@@ -16,7 +16,10 @@ import {
 	readAsFile,
 } from './download';
 import { withPHPIniValues } from './setup-php';
-import { playgroundMuPlugin } from '@wp-playground/wordpress';
+import {
+	playgroundMuPlugin,
+	preloadSqliteIntegration,
+} from '@wp-playground/wordpress';
 
 /**
  * Ensures a functional WordPress installation in php document root.
@@ -49,7 +52,9 @@ export async function setupWordPress(
 			monitor
 		),
 	]);
-	await prepareWordPress(php, wpZip, sqliteZip);
+
+	await prepareWordPress(php, wpZip);
+	await preloadSqliteIntegration(php, sqliteZip);
 
 	const preinstalledWpContentPath = path.join(
 		CACHE_FOLDER,
@@ -105,7 +110,7 @@ export async function setupWordPress(
  * accept the limitation, and switch to the PHP implementation as soon
  * as that's viable.
  */
-async function prepareWordPress(php: NodePHP, wpZip: File, sqliteZip: File) {
+async function prepareWordPress(php: NodePHP, wpZip: File) {
 	php.mkdir('/internal/shared/mu-plugins');
 	php.writeFile(
 		'/internal/shared/mu-plugins/0-playground.php',
@@ -128,33 +133,4 @@ async function prepareWordPress(php: NodePHP, wpZip: File, sqliteZip: File) {
 		'/wordpress/wp-config.php',
 		php.readFileAsText('/wordpress/wp-config-sample.php')
 	);
-	// }}}
-
-	// Setup the SQLite integration {{{
-	php.mkdir('/tmp/sqlite-database-integration');
-	await unzip(php, {
-		zipFile: sqliteZip,
-		extractToPath: '/tmp/sqlite-database-integration',
-	});
-	php.mv(
-		'/tmp/sqlite-database-integration/sqlite-database-integration-main',
-		'/internal/shared/mu-plugins/sqlite-database-integration'
-	);
-
-	const dbPhp = php
-		.readFileAsText(
-			'/internal/shared/mu-plugins/sqlite-database-integration/db.copy'
-		)
-		.replace(
-			"'{SQLITE_IMPLEMENTATION_FOLDER_PATH}'",
-			"'/internal/shared/mu-plugins/sqlite-database-integration/'"
-		)
-		.replace(
-			"'{SQLITE_PLUGIN}'",
-			"'/internal/shared/mu-plugins/sqlite-database-integration/load.php'"
-		);
-	// @TODO do not create the db.php file. Either find a way to mount it, or
-	//       load the custom $wpdb object in a different way.
-	php.writeFile('/wordpress/wp-content/db.php', dbPhp);
-	// }}}
 }
diff --git a/packages/playground/wordpress/package.json b/packages/playground/wordpress/package.json
@@ -26,8 +26,5 @@
 	"publishConfig": {
 		"access": "public",
 		"directory": "../../../dist/packages/playground/wordpress"
-	},
-	"dependencies": {
-		"@php-wasm/universal": "^0.6.6"
 	}
 }
diff --git a/packages/playground/wordpress/project.json b/packages/playground/wordpress/project.json
@@ -47,10 +47,7 @@
 			"executor": "@nx/linter:eslint",
 			"outputs": ["{options.outputFile}"],
 			"options": {
-				"lintFilePatterns": [
-					"packages/playground/wordpress/**/*.ts",
-					"packages/playground/wordpress/package.json"
-				]
+				"lintFilePatterns": ["packages/playground/wordpress/**/*.ts"]
 			}
 		}
 	},

diff --git a/packages/playground/wordpress/src/index.ts b/packages/playground/wordpress/src/index.ts
@@ -1,3 +1,7 @@
+import { UniversalPHP } from '@php-wasm/universal';
+import { joinPaths, phpVar } from '@php-wasm/util';
+import { unzip } from '@wp-playground/blueprints';
+
 export * from './rewrite-rules';
 
 export const RecommendedPHPVersion = '8.0';
@@ -105,3 +109,111 @@ export const specificMuPlugins = {
 export const playgroundMuPlugin = Object.values(specificMuPlugins)
 	.map((p) => p.trim())
 	.join('\n');
+
+export async function preloadSqliteIntegration(
+	php: UniversalPHP,
+	sqliteZip: File
+) {
+	if (await php.isDir('/tmp/sqlite-database-integration')) {
+		await php.rmdir('/tmp/sqlite-database-integration', {
+			recursive: true,
+		});
+	}
+	await php.mkdir('/tmp/sqlite-database-integration');
+	await unzip(php, {
+		zipFile: sqliteZip,
+		extractToPath: '/tmp/sqlite-database-integration',
+	});
+	const SQLITE_PLUGIN_FOLDER = '/internal/shared/sqlite-database-integration';
+	await php.mv(
+		'/tmp/sqlite-database-integration/sqlite-database-integration-main',
+		SQLITE_PLUGIN_FOLDER
+	);
+	const dbCopy = await php.readFileAsText(
+		joinPaths(SQLITE_PLUGIN_FOLDER, 'db.copy')
+	);
+	const dbPhp = dbCopy
+		.replace(
+			"'{SQLITE_IMPLEMENTATION_FOLDER_PATH}'",
+			phpVar(SQLITE_PLUGIN_FOLDER)
+		)
+		.replace(
+			"'{SQLITE_PLUGIN}'",
+			phpVar(joinPaths(SQLITE_PLUGIN_FOLDER, 'load.php'))
+		);
+	const SQLITE_MUPLUGIN_PATH =
+		'/internal/shared/mu-plugins/sqlite-database-integration.php';
+	await php.writeFile(SQLITE_MUPLUGIN_PATH, dbPhp);
+	await php.writeFile(
+		`/internal/shared/preload/0-sqlite.php`,
+		`<?php
+    /**
+     * Loads the SQLite integration plugin before WordPress is loaded
+     * and without creating a drop-in "db.php" file. 
+     *
+     * Technically, it creates a global $wpdb object whose only two
+     * purposes are to:
+     *
+     * * Exist – because the require_wp_db() WordPress function won't
+     *           connect to MySQL if $wpdb is already set.
+     * * Load the SQLite integration plugin the first time it's used
+     *   and replace the global $wpdb reference with the SQLite one.
+     *
+     * This lets Playground keep the WordPress installation clean and
+     * solves dillemas like:
+     *
+     * * Should we include db.php in Playground exports?
+     * * Should we remove db.php from Playground imports?
+     * * How should we treat stale db.php from long-lived OPFS sites?
+     *
+     * @see https://github.com/WordPress/wordpress-playground/discussions/1379 for
+     *      more context.
+     */
+    class Playground_SQLite_Integration_Loader {
+        public function __call($name, $arguments) {
+            $this->load_sqlite_integration();
+            if($GLOBALS['wpdb'] === $this) {
+                throw new Exception('Infinite loop detected in $wpdb – SQLite integration plugin could not be loaded');
+            }
+            return call_user_func_array(
+                array($GLOBALS['wpdb'], $name),
+                $arguments
+            );
+        }
+        public function __get($name) {
+            $this->load_sqlite_integration();
+            if($GLOBALS['wpdb'] === $this) {
+                throw new Exception('Infinite loop detected in $wpdb – SQLite integration plugin could not be loaded');
+            }
+            return $GLOBALS['wpdb']->$name;
+        }
+        public function __set($name, $value) {
+            $this->load_sqlite_integration();
+            if($GLOBALS['wpdb'] === $this) {
+                throw new Exception('Infinite loop detected in $wpdb – SQLite integration plugin could not be loaded');
+            }
+            $GLOBALS['wpdb']->$name = $value;
+        }
+        protected function load_sqlite_integration() {
+            require_once ${phpVar(SQLITE_MUPLUGIN_PATH)};
+        }
+    }
+    $wpdb = $GLOBALS['wpdb'] = new Playground_SQLite_Integration_Loader();
+            `
+	);
+	/**
+	 * Ensure the SQLite integration is loaded and clearly communicate
+	 * if it isn't. This is useful because WordPress database errors
+	 * may be cryptic and won't mention the SQLite integration.
+	 */
+	await php.writeFile(
+		`/internal/shared/mu-plugins/sqlite-test.php`,
+		`<?php
+            global $wpdb;
+            if(!($wpdb instanceof WP_SQLite_DB)) {
+                var_dump(isset($wpdb));
+                die("SQLite integration not loaded " . get_class($wpdb));
+            }
+            `
+	);
+}