Playground plugin: autologin fix, \n escaping, remove parent admin bar (#199)

Fixes #193

<!-- Thanks for contributing to WordPress Playground Tools! -->

## What?

This PR fixes a few issues reported in #193.
- Allows users to login if they don't use `admin/password` as login
credentials.
- Removes the parent admin bar from the sandbox page.
- Removes `\n` escaping from the DB exporter

## Why?

### Login

Users with custom usernames and passwords weren't automatically logged
into Playground because the credentials didn't match.

### Admin bar

We don't want the parent admin bar to be visible as it would be
confusing.

### \n

Initially, we decided to escape \n as a precaution, but it broke new
lines in post content and started displaying them as characters on the
page. Escaping isn't necessary and it breaks the export so we can remove
it.

## How?

### Login

By adding a mu-plugin using blueprints to programmatically login the
current user using their id.

### Admin bar

By hiding it with CSS on the Playground admin page.

### \n

By removing the escaping code.

## Testing Instructions

1. Check out the branch.
2. Install the plugin on a local WordPress site or use `wp-env`
3. On the local site update your password to be different from
_password_
4. Start a sandbox (wp-admin > Tools > Start Sandbox)
5. Confirm that the sandbox loaded and that you are logged in
6. If you are using the default WP theme open the Sample page by
clicking on the link in the header, if not open another page that has
multiple paragraphs with line breaks between them.
7. Confirm that there are no `\n` characters

Author: bgrgicak

packages/playground/assets/css/playground.css

@@ -14,6 +14,9 @@
 .tools_page_playground #wpbody {
 	position: initial;
 }
+.tools_page_playground #wpadminbar {
+	display: none;
+}
 
 #wp-playground-toolbar {
 	background-color: #eaaa00;

packages/playground/assets/js/playground.js

@@ -26,9 +26,6 @@
 					path: '/wordpress/schema/_Schema.sql',
 				},
 			},
-			{
-				step: 'login',
-			},
 		],
 	};
 
@@ -53,9 +50,29 @@
 
 	await client.isReady();
 
+	// Login as the current user without a password
+	await client.writeFile(
+		'/wordpress/playground-login.php',
+		`<?php
+		require_once( dirname( __FILE__ ) . '/wp-load.php' );
+		if ( is_user_logged_in() ) {
+			return;
+		}
+		$user = get_user_by( 'id', ${playground.userId} );
+		if( $user ) {
+			wp_set_current_user( $user->ID, $user->user_login );
+			wp_set_auth_cookie( $user->ID );
+			do_action( 'wp_login', $user->user_login, $user );
+		}`
+	);
+	await client.request({
+		url: '/playground-login.php',
+	});
+	await client.unlink('/wordpress/playground-login.php');
+
 	if (playground.pluginSlug) {
-		client.goTo('/wp-admin/plugins.php');
+		await client.goTo('/wp-admin/plugins.php');
 	} else {
-		client.goTo('/wp-admin');
+		await client.goTo('/wp-admin/');
 	}
 })();

packages/playground/playground.php

@@ -62,6 +62,7 @@ function enqueue_scripts($current_screen_id)
 		),
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
 		'pluginSlug' => isset($_GET['pluginSlug']) ? $_GET['pluginSlug'] : false,
+		'userId' => get_current_user_id(),
 	]);
 	wp_enqueue_script('playground');
 }

packages/playground/src/playground-db.php

@@ -18,7 +18,7 @@ function escape_array($array)
 		if (is_numeric($value)) {
 			$escaped[] = $wpdb->prepare('%d', $value);
 		} else {
-			$escaped[] = $wpdb->prepare('%s', str_replace("\n", "\\n", $value));
+			$escaped[] = $wpdb->prepare('%s', $value);
 		}
 	}
 	return implode(',', $escaped);