Plugin: Populate demo content by default content filters

gutenberg.php

@@ -254,19 +254,6 @@ function gutenberg_init( $return, $post ) {
 	return true;
 }
 
-/**
- * Redirects the demo page to edit a new post.
- */
-function gutenberg_redirect_demo() {
-	global $pagenow;
-
-	if ( 'admin.php' === $pagenow && isset( $_GET['page'] ) && 'gutenberg' === $_GET['page'] ) {
-		wp_safe_redirect( admin_url( 'post-new.php?gutenberg-demo' ) );
-		exit;
-	}
-}
-add_action( 'admin_init', 'gutenberg_redirect_demo' );
-
 /**
  * Adds the filters to register additional links for the Gutenberg editor in
  * the post/page screens.

lib/client-assets.php

@@ -865,8 +865,6 @@ function gutenberg_get_available_image_sizes() {
  * @param string $hook Screen name.
  */
 function gutenberg_editor_scripts_and_styles( $hook ) {
-	$is_demo = isset( $_GET['gutenberg-demo'] );
-
 	global $wp_scripts, $wp_meta_boxes;
 
 	// Add "wp-hooks" as dependency of "heartbeat".
@@ -983,17 +981,7 @@ function gutenberg_editor_scripts_and_styles( $hook ) {
 
 	// Assign initial edits, if applicable. These are not initially assigned
 	// to the persisted post, but should be included in its save payload.
-	if ( $is_new_post && $is_demo ) {
-		// Prepopulate with some test content in demo.
-		ob_start();
-		include gutenberg_dir_path() . 'post-content.php';
-		$demo_content = ob_get_clean();
-
-		$initial_edits = array(
-			'title'   => __( 'Welcome to the Gutenberg Editor', 'gutenberg' ),
-			'content' => $demo_content,
-		);
-	} elseif ( $is_new_post ) {
+	if ( $is_new_post ) {
 		// Override "(Auto Draft)" new post default title with empty string,
 		// or filtered value.
 		$initial_edits = array(

lib/demo.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * Supports for populating the Gutenberg demo content new post.
+ *
+ * @package gutenberg
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	die( 'Silence is golden.' );
+}
+
+/**
+ * Redirects the demo page to edit a new post.
+ */
+function gutenberg_redirect_demo() {
+	global $pagenow;
+
+	if ( 'admin.php' === $pagenow && isset( $_GET['page'] ) && 'gutenberg' === $_GET['page'] ) {
+		wp_safe_redirect( admin_url( 'post-new.php?gutenberg-demo' ) );
+		exit;
+	}
+}
+add_action( 'admin_init', 'gutenberg_redirect_demo' );
+
+/**
+ * Assigns the default content for the Gutenberg demo post.
+ *
+ * @param string $content Default post content.
+ *
+ * @return string Demo content if creating a new Gutenberg demo post, or the
+ *                default content otherwise.
+ */
+function gutenberg_default_demo_content( $content ) {
+	$is_demo = isset( $_GET['gutenberg-demo'] );
+
+	if ( $is_demo ) {
+		// Prepopulate with some test content in demo.
+		ob_start();
+		include gutenberg_dir_path() . 'post-content.php';
+		return ob_get_clean();
+	}
+
+	return $content;
+}
+add_filter( 'default_content', 'gutenberg_default_demo_content' );
+
+/**
+ * Assigns the default title for the Gutenberg demo post.
+ *
+ * @param string $title Default post title.
+ *
+ * @return string Demo title if creating a new Gutenberg demo post, or the
+ *                default title otherwise.
+ */
+function gutenberg_default_demo_title( $title ) {
+	$is_demo = isset( $_GET['gutenberg-demo'] );
+
+	if ( $is_demo ) {
+		return __( 'Welcome to the Gutenberg Editor', 'gutenberg' );
+	}
+
+	return $title;
+}
+add_filter( 'default_title', 'gutenberg_default_demo_title' );

lib/load.php

@@ -22,7 +22,7 @@
 require dirname( __FILE__ ) . '/plugin-compat.php';
 require dirname( __FILE__ ) . '/i18n.php';
 require dirname( __FILE__ ) . '/register.php';
-
+require dirname( __FILE__ ) . '/demo.php';
 
 // Register server-side code for individual blocks.
 if ( ! function_exists( 'render_block_core_archives' ) ) {