Adding Saburly Headless WP theme inspired by postlights serverless solution

wordpress/wp-content/themes/saburly-headless/functions.php

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+<?php
+// Logging functions
+require_once 'inc/log.php';
+
+// CORS handling
+require_once 'inc/cors.php';
+
+// Admin modifications
+require_once 'inc/admin.php';
+
+// Add Menus
+require_once 'inc/menus.php';
+
+// Add Headless Settings area
+require_once 'inc/acf-options.php';
+
+// Add custom API endpoints
+require_once 'inc/api-routes.php';

wordpress/wp-content/themes/saburly-headless/inc/admin.php

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+<?php
+/**
+ * By default, in Add/Edit Post, WordPress moves checked categories to the top of the list and unchecked to the bottom.
+ * When you have subcategories that you want to keep below their parents at all times, this makes no sense.
+ * This function removes automatic reordering so the categories widget retains its order regardless of checked state.
+ * Thanks to https://stackoverflow.com/a/12586404
+ *
+ * @param arr $args Array of arguments.
+ * @return arr
+ */
+function taxonomy_checklist_checked_ontop_filter( $args ) {
+    $args['checked_ontop'] = false;
+    return $args;
+}
+
+add_filter( 'wp_terms_checklist_args', 'taxonomy_checklist_checked_ontop_filter' );
+
+/**
+ * Customize the preview button in the WordPress admin to point to the headless client.
+ *
+ * @param  str $link The WordPress preview link.
+ * @return str The headless WordPress preview link.
+ */
+function set_headless_preview_link( $link ) {
+    return get_frontend_origin() . '/'
+        . '_preview/'
+        . get_the_ID() . '/'
+        . wp_create_nonce( 'wp_rest' );
+}
+
+add_filter( 'preview_post_link', 'set_headless_preview_link' );

wordpress/wp-content/themes/saburly-headless/inc/api-routes.php

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+<?php
+
+/**
+* Register custom REST API routes.
+ */
+add_action(
+    'rest_api_init',
+    function () {
+	// 	Define API endpoint arguments
+	        $slug_arg = [
+	            'validate_callback' => function ( $param, $request, $key ) {
+		return( is_string( $param ) );
+	}
+	,
+	        ];
+	$post_slug_arg = array_merge(
+	            $slug_arg,
+	            [
+	                'description' => 'String representing a valid WordPress post slug',
+	            ]
+	        );
+	$page_slug_arg = array_merge(
+	            $slug_arg,
+	            [
+	                'description' => 'String representing a valid WordPress page slug',
+	            ]
+	        );
+	
+	// 	Register routes
+	        register_rest_route( 'api/v1', '/post', [
+	            'methods'  => 'GET',
+	            'callback' => 'rest_get_post',
+	            'args' => [
+	                'slug' => array_merge(
+	                    $post_slug_arg,
+	                    [
+	                        'required' => true,
+	                    ]
+	                ),
+	            ],
+	        ] );
+	
+	register_rest_route( 'api/v1', '/page', [
+	            'methods'  => 'GET',
+	            'callback' => 'rest_get_page',
+	            'args' => [
+	                'slug' => array_merge(
+	                    $page_slug_arg,
+	                    [
+	                        'required' => true,
+	                    ]
+	                ),
+	            ],
+	        ] );
+	
+	register_rest_route('api/v1', '/post/preview', [
+	            'methods'  => 'GET',
+	            'callback' => 'rest_get_post_preview',
+	            'args' => [
+	                'id' => [
+	                    'validate_callback' => function ( $param, $request, $key ) {
+		return ( is_numeric( $param ) );
+	}
+	,
+	                    'required' => true,
+	                    'description' => 'Valid WordPress post ID',
+	                ],
+	            ],
+	            'permission_callback' => function () {
+		return current_user_can( 'edit_posts' );
+	}
+	,
+	        ] );
+}
+);
+
+
+/**
+* Respond to a REST API request to get post data.
+ *
+ * @param WP_REST_Request $request Request.
+ * @return WP_REST_Response
+ */
+function rest_get_post( WP_REST_Request $request ) {
+	return rest_get_content( $request, 'post', __FUNCTION__ );
+}
+
+
+/**
+* Respond to a REST API request to get page data.
+ *
+ * @param WP_REST_Request $request Request.
+ * @return WP_REST_Response
+ */
+function rest_get_page( WP_REST_Request $request ) {
+	return rest_get_content( $request, 'page', __FUNCTION__ );
+}
+
+
+/**
+* Respond to a REST API request to get post or page data.
+ * * Handles changed slugs
+ * * Doesn't return posts whose status isn't published
+ * * Redirects to the admin when an edit parameter is present
+ *
+ * @param WP_REST_Request $request Request
+ * @param str             $type Type
+ * @param str             $function_name Function name
+ * @return WP_REST_Response
+ */
+function rest_get_content( WP_REST_Request $request, $type, $function_name ) {
+	$content_in_array = in_array(
+	        $type,
+	        [
+	            'post',
+	            'page',
+	        ],
+	        true
+	    );
+	if ( ! $content_in_array ) {
+		$type = 'post';
+	}
+	$slug = $request->get_param( 'slug' );
+	$post = get_content_by_slug( $slug, $type );
+	if ( ! $post ) {
+		return new WP_Error(
+		            $function_name,
+		            $slug . ' ' . $type . ' does not exist',
+		            [
+		                'status' => 404,
+		            ]
+		        );
+	}
+	;
+	
+	// 	Shortcut to WP admin page editor
+	    $edit = $request->get_param( 'edit' );
+	if ( 'true' === $edit ) {
+		header( 'Location: /wp-admin/post.php?post=' . $post->ID . '&action=edit' );
+		exit;
+	}
+	$controller = new WP_REST_Posts_Controller( 'post' );
+	$data = $controller->prepare_item_for_response( $post, $request );
+	$response = $controller->prepare_response_for_collection( $data );
+	
+	return new WP_REST_Response( $response );
+}
+
+
+/**
+* Returns a post or page given a slug. Returns false if no post matches.
+ *
+ * @param str $slug Slug
+ * @param str $type Valid values are 'post' or 'page'
+ * @return Post
+ */
+function get_content_by_slug( $slug, $type = 'post' ) {
+	$content_in_array = in_array(
+	        $type,
+	        [
+	            'post',
+	            'page',
+	        ],
+	        true
+	    );
+	if ( ! $content_in_array ) {
+		$type = 'post';
+	}
+	$args = [
+	        'name'        => $slug,
+	        'post_type'   => $type,
+	        'post_status' => 'publish',
+	        'numberposts' => 1,
+	    ];
+	
+	// 	phpcs:ignore WordPress.VIP.RestrictedFunctions.get_posts_get_posts
+	    $post_search_results = get_posts( $args );
+	
+	if ( !$post_search_results ) {
+		// 		Maybe the slug changed
+		        // 		check wp_postmeta table for old slug
+		        $args = [
+		            // 		phpcs:ignore WordPress.VIP.SlowDBQuery.slow_db_query_meta_query
+		            'meta_query' => [
+		                [
+		                    'key' => '_wp_old_slug',
+		                    'value' => $post_slug,
+		                    'compare' => '=',
+		                ],
+		            ],
+		        ];
+		$query = new WP_Query( $args );
+		$post_search_results = $query->posts;
+	}
+	if ( isset( $post_search_results[0] ) ) {
+		return $post_search_results[0];
+	}
+	return false;
+}
+
+
+/**
+* Respond to a REST API request to get a post's latest revision.
+ * * Requires a valid _wpnonce on the query string
+ * * User must have 'edit_posts' rights
+ * * Will return draft revisions of even published posts
+ *
+ * @param  WP_REST_Request $request Rest request.
+ * @return WP_REST_Response
+ */
+function rest_get_post_preview( WP_REST_Request $request ) {
+    $post_id = $request->get_param( 'id' );
+    // Revisions are drafts so here we remove the default 'publish' status
+    remove_action( 'pre_get_posts', 'set_default_status_to_publish' );
+    $check_enabled = [
+        'check_enabled' => false,
+    ];
+    if ( $revisions = wp_get_post_revisions( $post_id, $check_enabled ) ) {
+        $last_revision = reset( $revisions );
+        $rev_post = wp_get_post_revision( $last_revision->ID );
+        $controller = new WP_REST_Posts_Controller( 'post' );
+        $data = $controller->prepare_item_for_response( $rev_post, $request );
+    } elseif ( $post = get_post( $post_id ) ) { // There are no revisions, just return the saved parent post
+        $controller = new WP_REST_Posts_Controller( 'post' );
+        $data = $controller->prepare_item_for_response( $post, $request );
+    } else {
+        $not_found = [
+            'status' => 404,
+        ];
+        $error = new WP_Error(
+            'rest_get_post_preview',
+            'Post ' . $post_id . ' does not exist',
+            $not_found
+        );
+        return $error;
+    }
+    $response = $controller->prepare_response_for_collection( $data );
+    return new WP_REST_Response( $response );
+}

wordpress/wp-content/themes/saburly-headless/inc/cors.php

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+<?php
+/**
+ * Allow GET requests from * origin
+ * Thanks to https://joshpress.net/access-control-headers-for-the-wordpress-rest-api/
+ */
+add_action( 'rest_api_init', function () {
+
+    remove_filter( 'rest_pre_serve_request', 'rest_send_cors_headers' );
+
+    add_filter( 'rest_pre_serve_request', function ( $value ) {
+        header( 'Access-Control-Allow-Origin: ' . get_frontend_origin() );
+        header( 'Access-Control-Allow-Methods: GET' );
+        header( 'Access-Control-Allow-Credentials: true' );
+        return $value;
+    });
+}, 15 );

wordpress/wp-content/themes/saburly-headless/inc/frontend-origin.php

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+<?php
+
+/**
+ * Placeholder function for determining the frontend origin.
+ *
+ * @TODO Determine the headless client's URL based on the current environment.
+ *
+ * @return str Frontend origin URL, i.e., http://localhost:3000.
+ */
+function get_frontend_origin() {
+    return 'http://localhost:3000';
+}

wordpress/wp-content/themes/saburly-headless/inc/log.php

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+<?php
+
+/**
+ * Logs messages/variables/data to browser console from within php
+ * Thanks to https://codeinphp.github.io/post/outputting-php-to-browser-console/
+ *
+ * To use this, in your PHP template inside PHP tags, add a line like this:
+ *  log_console('$mobile_image_size_inline_style var', $mobile_image_size_inline_style, true);
+ *
+ * @param str  $name message to be shown for optional data/vars
+ * @param str  $data variable (scalar/mixed) arrays/objects, etc to be logged
+ * @param bool $js_eval whether to apply JS eval() to arrays/objects
+ *
+ * @return none
+ * @author Sarfraz
+ */
+function log_console( $name, $data = null, $js_eval = false ) {
+    if ( ! $name ) {
+        return false;
+    }
+
+    $is_evaled = false;
+    $type = ( $data || gettype( $data ) ) ? 'Type: ' . gettype( $data ) : '';
+
+    if ( $js_eval && ( is_array( $data ) || is_object( $data ) ) ) {
+        $data = 'eval(' . preg_replace( '#[\s\r\n\t\0\x0B]+#', '', wp_json_encode( $data ) ) . ')';
+        $is_evaled = true;
+    } else {
+        $data = wp_json_encode( $data );
+    }
+
+    // sanitize
+    $data = $data ? $data : '';
+    $search_array = [ "#'#", '#""#', "#''#", "#\n#", "#\r\n#" ];
+    $replace_array = [ '"', '', '', '\\n', '\\n' ];
+    $data = preg_replace( $search_array,  $replace_array, $data );
+    $data = ltrim( rtrim( $data, '"' ), '"' );
+    $data = $is_evaled ? $data : ( "'" === $data[0] ) ? $data : "'" . $data . "'";
+
+    $js = <<<JSCODE
+\n<script>
+ // fallback - to deal with IE (or browsers that don't have console)
+ if (! window.console) console = {};
+ console.log = console.log || function(name, data){};
+ // end of fallback
+
+ console.log('$name');
+ console.log('------------------------------------------');
+ console.log('$type');
+ console.log($data);
+ console.log('\\n');
+</script>
+JSCODE;
+
+    echo $js; // phpcs:ignore WordPress.XSS.EscapeOutput.OutputNotEscaped
+}
+
+/**
+ * Log a value in wp-content/debug.log.
+ * To turn on, add the following to wp-config.php:
+ *
+ * define( 'WP_DEBUG', true );
+ * define( 'WP_DEBUG_LOG', true );  // Turn logging to wp-content/debug.log ON
+ * define( 'WP_DEBUG_DISPLAY', false ); // Keep JSON response valid
+ *
+ * @ini_set( 'display_errors', 0 ); // Keep JSON responses valid
+ *
+ * NOT INTENDED FOR PRODUCTION USE.
+ *
+ * @param str $message Message
+ * @param str $file Filename, defaults to __FILE__
+ * @param str $line Line number, defaults to __LINE__
+ * @return void
+ */
+function log_it( $message, $file = __FILE__, $line = __LINE__ ) {
+    // phpcs:disable WordPress
+    if ( WP_DEBUG === true ) {
+        if ( is_array( $message ) || is_object( $message ) ) {
+            error_log( $file . 'L' . $line . ' ' . ( print_r( $message, true ) ) );
+        } else {
+            error_log( $file . 'L' . $line . ' ' . $message );
+        }
+    }
+    // phpcs:enable WordPress
+}

wordpress/wp-content/themes/saburly-headless/inc/menus.php

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+<?php
+
+
+/**
+* Register navigation menu.
+ *
+ * @return void
+ */
+function register_menus() {
+	register_nav_menu( 'header-menu', __( 'Header Menu', 'saburly-wp' ) );
+}
+add_action( 'after_setup_theme', 'register_menus' );

wordpress/wp-content/themes/saburly-headless/index.php

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+<?php
+// Redirect individual post and pages to the REST API endpoint
+if ( is_single() ) {
+    header( 'Location: /wp-json/wp/v2/posts/' . get_post()->ID );
+} elseif ( is_page() ) {
+    header( 'Location: /wp-json/wp/v2/pages/' . get_queried_object()->ID );
+} else {
+    header( 'Location: /wp-json/' );
+}

wordpress/wp-content/themes/saburly-headless/post-content/sample-post.txt

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+Welcome to WordPress. This is your first post. <a href="http://localhost:8080/wp-json/api/v1/post?slug=sample-post&edit=true" target="_new">Edit</a> or delete it, then start writing!

wordpress/wp-content/themes/saburly-headless/post-content/welcome.txt

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+You've successfully installed wordpress

wordpress/wp-content/themes/saburly-headless/style.css

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+/*
+Theme Name: Saburly Website
+Theme URI: https://www.saburly.com
+Author: Saburly
+Author URI: https://saburly.com
+Description: Headless Wordpress API for Saburly.com
+*/