tomevault-io Advanced WordPress Architecture
Master advanced WordPress development patterns including REST API endpoints, WP-CLI commands, performance optimization, and caching strategies for scalable WordPress applications.
1. REST API Development
The WordPress REST API provides a powerful interface for creating custom endpoints with proper authentication, validation, and response formatting.
Endpoint Registration with Namespacing
add_action( 'rest_api_init', 'register_custom_rest_routes' );
function register_custom_rest_routes() {
// Namespace: myplugin/v1 (enables versioning)
$namespace = 'myplugin/v1';
// GET /wp-json/myplugin/v1/books
register_rest_route( $namespace, '/books', [
'methods' => 'GET',
'callback' => 'get_books_callback',
'permission_callback' => '__return_true', // Public endpoint
'args' => [
'per_page' => [
'default' => 10,
'validate_callback' => function( $param ) {
return is_numeric( $param ) && $param > 0 && $param <= 100;
},
'sanitize_callback' => 'absint',
],
'page' => [
'default' => 1,
'validate_callback' => function( $param ) {
return is_numeric( $param ) && $param > 0;
},
'sanitize_callback' => 'absint',
],
],
]);
// GET /wp-json/myplugin/v1/books/(?P<id>\d+)
register_rest_route( $namespace, '/books/(?P<id>\d+)', [
'methods' => 'GET',
'callback' => 'get_book_callback',
'permission_callback' => '__return_true',
'args' => [
'id' => [
'validate_callback' => function( $param ) {
return is_numeric( $param );
},
'sanitize_callback' => 'absint',
],
],
]);
// POST /wp-json/myplugin/v1/books (authenticated)
register_rest_route( $namespace, '/books', [
'methods' => 'POST',
'callback' => 'create_book_callback',
'permission_callback' => function() {
return current_user_can( 'edit_posts' );
},
'args' => [
'title' => [
'required' => true,
'type' => 'string',
'validate_callback' => function( $param ) {
return is_string( $param ) && strlen( $param ) > 0;
},
'sanitize_callback' => 'sanitize_text_field',
],
'content' => [
'required' => false,
'type' => 'string',
'sanitize_callback' => 'wp_kses_post',
],
'status' => [
'default' => 'draft',
'enum' => [ 'draft', 'publish', 'private' ],
],
],
]);
// PUT /wp-json/myplugin/v1/books/(?P<id>\d+)
register_rest_route( $namespace, '/books/(?P<id>\d+)', [
'methods' => 'PUT',
'callback' => 'update_book_callback',
'permission_callback' => function( $request ) {
$book_id = $request->get_param( 'id' );
return current_user_can( 'edit_post', $book_id );
},
'args' => [
'id' => [
'validate_callback' => function( $param ) {
return is_numeric( $param );
},
'sanitize_callback' => 'absint',
],
'title' => [
'type' => 'string',
'sanitize_callback' => 'sanitize_text_field',
],
'content' => [
'type' => 'string',
'sanitize_callback' => 'wp_kses_post',
],
],
]);
// DELETE /wp-json/myplugin/v1/books/(?P<id>\d+)
register_rest_route( $namespace, '/books/(?P<id>\d+)', [
'methods' => 'DELETE',
'callback' => 'delete_book_callback',
'permission_callback' => function( $request ) {
$book_id = $request->get_param( 'id' );
return current_user_can( 'delete_post', $book_id );
},
'args' => [
'id' => [
'validate_callback' => function( $param ) {
return is_numeric( $param );
},
'sanitize_callback' => 'absint',
],
],
]);
}
Complete CRUD Implementation
// GET /wp-json/myplugin/v1/books
function get_books_callback( $request ) {
$per_page = $request->get_param( 'per_page' );
$page = $request->get_param( 'page' );
$offset = ( $page - 1 ) * $per_page;
$args = [
'post_type' => 'book',
'posts_per_page' => $per_page,
'offset' => $offset,
'post_status' => 'publish',
];
$query = new WP_Query( $args );
if ( ! $query->have_posts() ) {
return rest_ensure_response([
'books' => [],
'total' => 0,
'page' => $page,
'per_page' => $per_page,
]);
}
$books = [];
while ( $query->have_posts() ) {
$query->the_post();
$books[] = [
'id' => get_the_ID(),
'title' => get_the_title(),
'content' => get_the_content(),
'author' => get_the_author(),
'date' => get_the_date( 'c' ), // ISO 8601 format
'link' => get_permalink(),
];
}
wp_reset_postdata();
$response = rest_ensure_response([
'books' => $books,
'total' => $query->found_posts,
'page' => $page,
'per_page' => $per_page,
'total_pages' => ceil( $query->found_posts / $per_page ),
]);
// Add HATEOAS links
$response->add_link( 'self', rest_url( "myplugin/v1/books?page={$page}&per_page={$per_page}" ) );
if ( $page > 1 ) {
$prev_page = $page - 1;
$response->add_link( 'prev', rest_url( "myplugin/v1/books?page={$prev_page}&per_page={$per_page}" ) );
}
if ( $page < ceil( $query->found_posts / $per_page ) ) {
$next_page = $page + 1;
$response->add_link( 'next', rest_url( "myplugin/v1/books?page={$next_page}&per_page={$per_page}" ) );
}
return $response;
}
// GET /wp-json/myplugin/v1/books/123
function get_book_callback( $request ) {
$book_id = $request->get_param( 'id' );
$book = get_post( $book_id );
if ( ! $book || 'book' !== $book->post_type ) {
return new WP_Error(
'book_not_found',
'Book not found',
[ 'status' => 404 ]
);
}
$data = [
'id' => $book->ID,
'title' => $book->post_title,
'content' => apply_filters( 'the_content', $book->post_content ),
'excerpt' => $book->post_excerpt,
'author' => get_the_author_meta( 'display_name', $book->post_author ),
'date' => get_the_date( 'c', $book ),
'modified' => get_the_modified_date( 'c', $book ),
'status' => $book->post_status,
'link' => get_permalink( $book ),
'featured_image' => get_the_post_thumbnail_url( $book, 'large' ),
'meta' => [
'isbn' => get_post_meta( $book->ID, '_isbn', true ),
'pages' => (int) get_post_meta( $book->ID, '_pages', true ),
],
];
return rest_ensure_response( $data );
}
// POST /wp-json/myplugin/v1/books
function create_book_callback( $request ) {
$title = $request->get_param( 'title' );
$content = $request->get_param( 'content' );
$status = $request->get_param( 'status' );
$post_data = [
'post_type' => 'book',
'post_title' => $title,
'post_content' => $content,
'post_status' => $status,
'post_author' => get_current_user_id(),
];
$book_id = wp_insert_post( $post_data, true );
if ( is_wp_error( $book_id ) ) {
return new WP_Error(
'book_creation_failed',
$book_id->get_error_message(),
[ 'status' => 500 ]
);
}
// Add custom metadata if provided
if ( $request->has_param( 'isbn' ) ) {
update_post_meta( $book_id, '_isbn', sanitize_text_field( $request->get_param( 'isbn' ) ) );
}
if ( $request->has_param( 'pages' ) ) {
update_post_meta( $book_id, '_pages', absint( $request->get_param( 'pages' ) ) );
}
$response = rest_ensure_response([
'id' => $book_id,
'title' => $title,
'message' => 'Book created successfully',
'link' => get_permalink( $book_id ),
]);
$response->set_status( 201 ); // Created
$response->header( 'Location', rest_url( "myplugin/v1/books/{$book_id}" ) );
return $response;
}
// PUT /wp-json/myplugin/v1/books/123
function update_book_callback( $request ) {
$book_id = $request->get_param( 'id' );
$book = get_post( $book_id );
if ( ! $book || 'book' !== $book->post_type ) {
return new WP_Error(
'book_not_found',
'Book not found',
[ 'status' => 404 ]
);
}
$post_data = [ 'ID' => $book_id ];
if ( $request->has_param( 'title' ) ) {
$post_data['post_title'] = $request->get_param( 'title' );
}
if ( $request->has_param( 'content' ) ) {
$post_data['post_content'] = $request->get_param( 'content' );
}
if ( $request->has_param( 'status' ) ) {
$post_data['post_status'] = $request->get_param( 'status' );
}
$result = wp_update_post( $post_data, true );
if ( is_wp_error( $result ) ) {
return new WP_Error(
'book_update_failed',
$result->get_error_message(),
[ 'status' => 500 ]
);
}
return rest_ensure_response([
'id' => $book_id,
'message' => 'Book updated successfully',
'link' => get_permalink( $book_id ),
]);
}
// DELETE /wp-json/myplugin/v1/books/123
function delete_book_callback( $request ) {
$book_id = $request->get_param( 'id' );
$book = get_post( $book_id );
if ( ! $book || 'book' !== $book->post_type ) {
return new WP_Error(
'book_not_found',
'Book not found',
[ 'status' => 404 ]
);
}
// Soft delete (trash) or hard delete
$force = $request->get_param( 'force' );
$result = wp_delete_post( $book_id, $force );
if ( ! $result ) {
return new WP_Error(
'book_deletion_failed',
'Failed to delete book',
[ 'status' => 500 ]
);
}
return rest_ensure_response([
'deleted' => true,
'id' => $book_id,
'message' => $force ? 'Book permanently deleted' : 'Book moved to trash',
]);
}
Controller Pattern for Complex Endpoints
For complex REST endpoints, use a controller class to organize logic:
<?php
namespace MyPlugin\API;
class Books_Controller extends \WP_REST_Controller {
protected $namespace = 'myplugin/v1';
protected $rest_base = 'books';
public function register_routes() {
register_rest_route( $this->namespace, '/' . $this->rest_base, [
[
'methods' => \WP_REST_Server::READABLE,
'callback' => [ $this, 'get_items' ],
'permission_callback' => [ $this, 'get_items_permissions_check' ],
'args' => $this->get_collection_params(),
],
[
'methods' => \WP_REST_Server::CREATABLE,
'callback' => [ $this, 'create_item' ],
'permission_callback' => [ $this, 'create_item_permissions_check' ],
'args' => $this->get_endpoint_args_for_item_schema( \WP_REST_Server::CREATABLE ),
],
'schema' => [ $this, 'get_public_item_schema' ],
]);
register_rest_route( $this->namespace, '/' . $this->rest_base . '/(?P<id>[\d]+)', [
'args' => [
'id' => [
'description' => 'Unique identifier for the book',
'type' => 'integer',
],
],
[
'methods' => \WP_REST_Server::READABLE,
'callback' => [ $this, 'get_item' ],
'permission_callback' => [ $this, 'get_item_permissions_check' ],
'args' => [
'context' => $this->get_context_param( [ 'default' => 'view' ] ),
],
],
[
'methods' => \WP_REST_Server::EDITABLE,
'callback' => [ $this, 'update_item' ],
'permission_callback' => [ $this, 'update_item_permissions_check' ],
'args' => $this->get_endpoint_args_for_item_schema( \WP_REST_Server::EDITABLE ),
],
[
'methods' => \WP_REST_Server::DELETABLE,
'callback' => [ $this, 'delete_item' ],
'permission_callback' => [ $this, 'delete_item_permissions_check' ],
'args' => [
'force' => [
'type' => 'boolean',
'default' => false,
'description' => 'Whether to bypass trash and force deletion',
],
],
],
'schema' => [ $this, 'get_public_item_schema' ],
]);
}
public function get_items( $request ) {
// Implementation similar to get_books_callback above
}
public function get_item( $request ) {
// Implementation similar to get_book_callback above
}
public function create_item( $request ) {
// Implementation similar to create_book_callback above
}
public function update_item( $request ) {
// Implementation similar to update_book_callback above
}
public function delete_item( $request ) {
// Implementation similar to delete_book_callback above
}
public function get_items_permissions_check( $request ) {
return true; // Public endpoint
}
public function get_item_permissions_check( $request ) {
return true; // Public endpoint
}
public function create_item_permissions_check( $request ) {
return current_user_can( 'edit_posts' );
}
public function update_item_permissions_check( $request ) {
$book_id = $request->get_param( 'id' );
return current_user_can( 'edit_post', $book_id );
}
public function delete_item_permissions_check( $request ) {
$book_id = $request->get_param( 'id' );
return current_user_can( 'delete_post', $book_id );
}
public function get_public_item_schema() {
if ( $this->schema ) {
return $this->add_additional_fields_schema( $this->schema );
}
$schema = [
'$schema' => 'http://json-schema.org/draft-04/schema#',
'title' => 'book',
'type' => 'object',
'properties' => [
'id' => [
'description' => 'Unique identifier for the book',
'type' => 'integer',
'context' => [ 'view', 'edit', 'embed' ],
'readonly' => true,
],
'title' => [
'description' => 'The book title',
'type' => 'string',
'context' => [ 'view', 'edit', 'embed' ],
'required' => true,
],
'content' => [
'description' => 'The book content',
'type' => 'string',
'context' => [ 'view', 'edit' ],
],
'status' => [
'description' => 'The book status',
'type' => 'string',
'enum' => [ 'draft', 'publish', 'private' ],
'context' => [ 'view', 'edit' ],
],
],
];
$this->schema = $schema;
return $this->add_additional_fields_schema( $this->schema );
}
}
// Register controller
add_action( 'rest_api_init', function() {
$controller = new \MyPlugin\API\Books_Controller();
$controller->register_routes();
});
REST API Authentication
// Application Passwords (WordPress 5.6+)
// Users generate passwords at /wp-admin/profile.php
// Example cURL request with authentication:
// curl -X POST https://example.com/wp-json/myplugin/v1/books \
// -u username:application_password \
// -H "Content-Type: application/json" \
// -d '{"title":"New Book","content":"Book content"}'
// Cookie authentication for logged-in users (requires nonce)
add_action( 'rest_api_init', function() {
// Add nonce to wp_localize_script
wp_localize_script( 'my-ajax-script', 'wpApiSettings', [
'root' => esc_url_raw( rest_url() ),
'nonce' => wp_create_nonce( 'wp_rest' ),
]);
});
// JavaScript REST API call with nonce:
/*
fetch( wpApiSettings.root + 'myplugin/v1/books', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'X-WP-Nonce': wpApiSettings.nonce
},
body: JSON.stringify({
title: 'New Book',
content: 'Book content'
})
}).then( response => response.json() )
.then( data => console.log( data ) );
*/
2. WP-CLI Commands
WP-CLI enables automation of WordPress tasks through custom commands.
Custom Command Registration
<?php
namespace MyPlugin\CLI;
class Books_Command {
/**
* List all books.
*
* ## OPTIONS
*
* [--format=<format>]
* : Render output in a particular format.
* ---
* default: table
* options:
* - table
* - csv
* - json
* - yaml
* ---
*
* [--status=<status>]
* : Filter by post status.
*
* ## EXAMPLES
*
* wp books list
* wp books list --format=json
* wp books list --status=publish
*
* @when after_wp_load
*/
public function list( $args, $assoc_args ) {
$defaults = [
'format' => 'table',
'status' => 'any',
];
$assoc_args = wp_parse_args( $assoc_args, $defaults );
$query_args = [
'post_type' => 'book',
'posts_per_page' => -1,
'post_status' => $assoc_args['status'],
];
$books = get_posts( $query_args );
if ( empty( $books ) ) {
\WP_CLI::warning( 'No books found.' );
return;
}
$items = [];
foreach ( $books as $book ) {
$items[] = [
'ID' => $book->ID,
'Title' => $book->post_title,
'Status' => $book->post_status,
'Author' => get_the_author_meta( 'display_name', $book->post_author ),
'Date' => get_the_date( 'Y-m-d H:i:s', $book ),
];
}
\WP_CLI\Utils\format_items( $assoc_args['format'], $items, [ 'ID', 'Title', 'Status', 'Author', 'Date' ] );
\WP_CLI::success( sprintf( 'Found %d books.', count( $items ) ) );
}
/**
* Create a new book.
*
* ## OPTIONS
*
* <title>
* : The book title.
*
* [--content=<content>]
* : The book content.
*
* [--status=<status>]
* : The book status.
* ---
* default: draft
* options:
* - draft
* - publish
* - private
* ---
*
* [--isbn=<isbn>]
* : The book ISBN.
*
* [--pages=<pages>]
* : Number of pages.
*
* ## EXAMPLES
*
* wp books create "My Book Title"
* wp books create "My Book" --status=publish --isbn=978-3-16-148410-0 --pages=350
*
* @when after_wp_load
*/
public function create( $args, $assoc_args ) {
$title = $args[0];
$defaults = [
'content' => '',
'status' => 'draft',
];
$assoc_args = wp_parse_args( $assoc_args, $defaults );
$post_data = [
'post_type' => 'book',
'post_title' => $title,
'post_content' => $assoc_args['content'],
'post_status' => $assoc_args['status'],
'post_author' => get_current_user_id(),
];
$book_id = wp_insert_post( $post_data, true );
if ( is_wp_error( $book_id ) ) {
\WP_CLI::error( 'Failed to create book: ' . $book_id->get_error_message() );
}
// Add custom metadata
if ( isset( $assoc_args['isbn'] ) ) {
update_post_meta( $book_id, '_isbn', sanitize_text_field( $assoc_args['isbn'] ) );
}
if ( isset( $assoc_args['pages'] ) ) {
update_post_meta( $book_id, '_pages', absint( $assoc_args['pages'] ) );
}
\WP_CLI::success( sprintf( 'Created book #%d: %s', $book_id, $title ) );
}
/**
* Import books from CSV file.
*
* ## OPTIONS
*
* <file>
* : Path to CSV file.
*
* [--dry-run]
* : Preview import without creating books.
*
* ## EXAMPLES
*
* wp books import books.csv
* wp books import books.csv --dry-run
*
* @when after_wp_load
*/
public function import( $args, $assoc_args ) {
$file = $args[0];
$dry_run = isset( $assoc_args['dry-run'] );
if ( ! file_exists( $file ) ) {
\WP_CLI::error( 'File not found: ' . $file );
}
$csv = array_map( 'str_getcsv', file( $file ) );
$header = array_shift( $csv );
$total = count( $csv );
$created = 0;
\WP_CLI::log( sprintf( 'Processing %d books...', $total ) );
$progress = \WP_CLI\Utils\make_progress_bar( 'Importing books', $total );
foreach ( $csv as $row ) {
$book = array_combine( $header, $row );
if ( $dry_run ) {
\WP_CLI::log( sprintf( 'Would create: %s', $book['title'] ) );
} else {
$post_data = [
'post_type' => 'book',
'post_title' => $book['title'],
'post_content' => $book['content'] ?? '',
'post_status' => $book['status'] ?? 'draft',
];
$book_id = wp_insert_post( $post_data, true );
if ( ! is_wp_error( $book_id ) ) {
if ( isset( $book['isbn'] ) ) {
update_post_meta( $book_id, '_isbn', $book['isbn'] );
}
$created++;
}
}
$progress->tick();
}
$progress->finish();
if ( $dry_run ) {
\WP_CLI::success( sprintf( 'Dry run complete. Would create %d books.', $total ) );
} else {
\WP_CLI::success( sprintf( 'Imported %d of %d books.', $created, $total ) );
}
}
/**
* Generate sample books.
*
* ## OPTIONS
*
* [--count=<count>]
* : Number of books to generate.
* ---
* default: 10
* ---
*
* [--status=<status>]
* : Book status.
* ---
* default: publish
* ---
*
* ## EXAMPLES
*
* wp books generate --count=50
* wp books generate --count=100 --status=draft
*
* @when after_wp_load
*/
public function generate( $args, $assoc_args ) {
$count = isset( $assoc_args['count'] ) ? absint( $assoc_args['count'] ) : 10;
$status = isset( $assoc_args['status'] ) ? $assoc_args['status'] : 'publish';
$progress = \WP_CLI\Utils\make_progress_bar( 'Generating books', $count );
for ( $i = 1; $i <= $count; $i++ ) {
$post_data = [
'post_type' => 'book',
'post_title' => sprintf( 'Sample Book %d', $i ),
'post_content' => sprintf( 'This is sample book number %d.', $i ),
'post_status' => $status,
];
$book_id = wp_insert_post( $post_data );
// Add random metadata
update_post_meta( $book_id, '_isbn', sprintf( '978-3-16-%06d-0', rand( 100000, 999999 ) ) );
update_post_meta( $book_id, '_pages', rand( 100, 500 ) );
$progress->tick();
}
$progress->finish();
\WP_CLI::success( sprintf( 'Generated %d books.', $count ) );
}
}
// Register WP-CLI command
if ( defined( 'WP_CLI' ) && WP_CLI ) {
\WP_CLI::add_command( 'books', 'MyPlugin\CLI\Books_Command' );
}
Interactive Prompts and Confirmation
/**
* Delete all books (with confirmation).
*
* ## OPTIONS
*
* [--yes]
* : Skip confirmation prompt.
*
* ## EXAMPLES
*
* wp books delete-all
* wp books delete-all --yes
*
* @when after_wp_load
*/
public function delete_all( $args, $assoc_args ) {
$books = get_posts([
'post_type' => 'book',
'posts_per_page' => -1,
'fields' => 'ids',
]);
$count = count( $books );
if ( 0 === $count ) {
\WP_CLI::warning( 'No books to delete.' );
return;
}
// Prompt for confirmation unless --yes flag is provided
\WP_CLI::confirm( sprintf( 'Are you sure you want to delete %d books?', $count ), $assoc_args );
$progress = \WP_CLI\Utils\make_progress_bar( 'Deleting books', $count );
foreach ( $books as $book_id ) {
wp_delete_post( $book_id, true ); // Force delete
$progress->tick();
}
$progress->finish();
\WP_CLI::success( sprintf( 'Deleted %d books.', $count ) );
}
Testing WP-CLI Commands
# List all WP-CLI commands
wp cli command-list
# Get help for custom command
wp help books
wp help books create
# Test commands
wp books list
wp books list --format=json
wp books create "Test Book" --status=publish
wp books generate --count=50
wp books import books.csv --dry-run
wp books delete-all --yes
3. Performance Optimization
Transients API (Expiring Cache)
// Store data with expiration
function get_popular_books() {
$transient_key = 'popular_books';
// Try to get cached value
$popular_books = get_transient( $transient_key );
if ( false === $popular_books ) {
// Cache miss - fetch and store
$popular_books = new WP_Query([
'post_type' => 'book',
'posts_per_page' => 10,
'meta_key' => '_view_count',
'orderby' => 'meta_value_num',
'order' => 'DESC',
]);
// Cache for 1 hour (3600 seconds)
set_transient( $transient_key, $popular_books, HOUR_IN_SECONDS );
}
return $popular_books;
}
// Invalidate cache on post update
add_action( 'save_post_book', 'invalidate_books_cache' );
function invalidate_books_cache( $post_id ) {
delete_transient( 'popular_books' );
}
// Site-specific transients (multisite)
set_site_transient( 'network_data', $data, DAY_IN_SECONDS );
$data = get_site_transient( 'network_data' );
delete_site_transient( 'network_data' );
// Clear all transients (cleanup)
global $wpdb;
$wpdb->query( "DELETE FROM $wpdb->options WHERE option_name LIKE '%_transient_%'" );
Object Caching (Redis, Memcached)
// WordPress Object Cache functions (wp_cache_*)
// Works with persistent cache (Redis/Memcached) if configured
// Add to cache
wp_cache_add( 'my_key', $data, 'my_group', 3600 );
// Get from cache
$data = wp_cache_get( 'my_key', 'my_group' );
if ( false === $data ) {
// Cache miss - fetch and cache
$data = expensive_database_query();
wp_cache_set( 'my_key', $data, 'my_group', 3600 );
}
// Delete from cache
wp_cache_delete( 'my_key', 'my_group' );
// Flush entire cache
wp_cache_flush();
// Example: Cache user data
function get_user_books( $user_id ) {
$cache_key = "user_{$user_id}_books";
$cache_group = 'user_books';
$books = wp_cache_get( $cache_key, $cache_group );
if ( false === $books ) {
$books = get_posts([
'post_type' => 'book',
'author' => $user_id,
'posts_per_page' => -1,
]);
wp_cache_set( $cache_key, $books, $cache_group, HOUR_IN_SECONDS );
}
return $books;
}
// Invalidate user cache on book update
add_action( 'save_post_book', 'invalidate_user_books_cache', 10, 2 );
function invalidate_user_books_cache( $post_id, $post ) {
wp_cache_delete( "user_{$post->post_author}_books", 'user_books' );
}
Redis Configuration (object-cache.php)
// Install Redis plugin or drop-in
// Recommended: https://wordpress.org/plugins/redis-cache/
// Or manual configuration:
// wp-content/object-cache.php
<?php
// Redis configuration
global $redis_server;
$redis_server = [
'host' => '127.0.0.1',
'port' => 6379,
'auth' => '', // Password if required
'database' => 0, // Redis database number
];
// wp-config.php settings
define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 0 );
define( 'WP_REDIS_TIMEOUT', 1 );
define( 'WP_REDIS_READ_TIMEOUT', 1 );
Database Query Optimization
// BAD: Multiple queries in loop
$posts = get_posts([ 'post_type' => 'book', 'posts_per_page' => -1 ]);
foreach ( $posts as $post ) {
$author = get_user_by( 'id', $post->post_author ); // N+1 query problem
$meta = get_post_meta( $post->ID, '_isbn', true ); // Another query per iteration
}
// GOOD: Pre-fetch data
$posts = get_posts([ 'post_type' => 'book', 'posts_per_page' => -1 ]);
$author_ids = wp_list_pluck( $posts, 'post_author' );
$authors = get_users([ 'include' => $author_ids ]); // Single query
$authors_by_id = [];
foreach ( $authors as $author ) {
$authors_by_id[ $author->ID ] = $author;
}
// Pre-load all meta with update_meta_cache()
update_post_caches( $posts, 'book' );
foreach ( $posts as $post ) {
$author = $authors_by_id[ $post->post_author ];
$isbn = get_post_meta( $post->ID, '_isbn', true ); // Uses cache
}
// Custom queries with JOIN
global $wpdb;
$results = $wpdb->get_results("
SELECT p.*, pm.meta_value as isbn
FROM {$wpdb->posts} p
LEFT JOIN {$wpdb->postmeta} pm ON p.ID = pm.post_id AND pm.meta_key = '_isbn'
WHERE p.post_type = 'book'
AND p.post_status = 'publish'
ORDER BY p.post_date DESC
LIMIT 10
");
// Add database indexes for frequently queried meta
global $wpdb;
$wpdb->query("
CREATE INDEX meta_key_value ON {$wpdb->postmeta} (meta_key, meta_value(20))
");
Lazy Loading and Pagination
// Paginate large queries
function get_books_paginated( $page = 1, $per_page = 20 ) {
$args = [
'post_type' => 'book',
'posts_per_page' => $per_page,
'paged' => $page,
];
return new WP_Query( $args );
}
// Infinite scroll with AJAX
add_action( 'wp_ajax_load_more_books', 'ajax_load_more_books' );
add_action( 'wp_ajax_nopriv_load_more_books', 'ajax_load_more_books' );
function ajax_load_more_books() {
check_ajax_referer( 'load_more_nonce', 'nonce' );
$page = isset( $_POST['page'] ) ? absint( $_POST['page'] ) : 1;
$query = get_books_paginated( $page, 10 );
if ( $query->have_posts() ) {
ob_start();
while ( $query->have_posts() ) {
$query->the_post();
get_template_part( 'template-parts/content', 'book' );
}
$html = ob_get_clean();
wp_send_json_success([
'html' => $html,
'has_more' => $query->max_num_pages > $page,
]);
} else {
wp_send_json_error( 'No more books' );
}
}
// Lazy load images (native HTML)
<img src="book-cover.jpg" loading="lazy" alt="Book Cover">
Profiling with Query Monitor
// Install Query Monitor plugin
// https://wordpress.org/plugins/query-monitor/
// Add custom timing measurements
do_action( 'qm/start', 'my_expensive_operation' );
// ... expensive code ...
do_action( 'qm/stop', 'my_expensive_operation' );
// Log custom data
do_action( 'qm/debug', 'Custom debug message' );
do_action( 'qm/info', $data_to_inspect );
// Benchmark queries
Query Monitor shows:
// - SQL queries (count, time, duplicates)
// - HTTP requests
// - Hooks and actions
// - PHP errors and notices
// - Template file hierarchy
// - Enqueued scripts/styles
4. Caching Strategies
Fragment Caching
// Cache HTML fragments
function render_book_grid() {
$cache_key = 'book_grid_html';
$html = get_transient( $cache_key );
if ( false === $html ) {
ob_start();
$books = new WP_Query([
'post_type' => 'book',
'posts_per_page' => 12,
]);
if ( $books->have_posts() ) {
echo '<div class="book-grid">';
while ( $books->have_posts() ) {
$books->the_post();
?>
<div class="book-item">
<h3><?php the_title(); ?></h3>
<?php the_post_thumbnail( 'medium' ); ?>
</div>
<?php
}
echo '</div>';
}
wp_reset_postdata();
$html = ob_get_clean();
set_transient( $cache_key, $html, HOUR_IN_SECONDS );
}
echo $html;
}
Page Caching vs Object Caching
/**
* Page Caching:
* - Caches entire HTML pages
* - Fastest (serves static HTML)
* - Plugins: WP Super Cache, W3 Total Cache, WP Rocket
* - Bypassed for logged-in users
*
* Object Caching:
* - Caches database queries and computed values
* - Works for all users (logged-in and anonymous)
* - Requires persistent cache backend (Redis, Memcached)
* - Granular cache control
*/
// Example: Bypass page cache for dynamic content
header( 'Cache-Control: no-cache, must-revalidate, max-age=0' );
// Cache-Control headers for static assets
function add_cache_headers() {
if ( is_admin() || is_user_logged_in() ) {
return;
}
// Cache static pages for 1 hour
if ( is_page() || is_single() ) {
header( 'Cache-Control: public, max-age=3600' );
}
// Cache archives for 30 minutes
if ( is_archive() || is_home() ) {
header( 'Cache-Control: public, max-age=1800' );
}
}
add_action( 'send_headers', 'add_cache_headers' );
Cache Invalidation Patterns
// Pattern 1: Time-based expiration
set_transient( 'data', $value, 12 * HOUR_IN_SECONDS );
// Pattern 2: Event-based invalidation
add_action( 'save_post_book', 'clear_book_caches' );
function clear_book_caches( $post_id ) {
// Clear specific caches
delete_transient( 'popular_books' );
delete_transient( 'recent_books' );
wp_cache_delete( "book_{$post_id}", 'books' );
// Clear author cache
$post = get_post( $post_id );
wp_cache_delete( "user_{$post->post_author}_books", 'user_books' );
}
// Pattern 3: Versioned cache keys
function get_cache_version() {
$version = wp_cache_get( 'cache_version', 'global' );
if ( false === $version ) {
$version = time();
wp_cache_set( 'cache_version', $version, 'global' );
}
return $version;
}
function get_cached_data( $key ) {
$version = get_cache_version();
$versioned_key = "{$key}_v{$version}";
return wp_cache_get( $versioned_key, 'my_group' );
}
function set_cached_data( $key, $data ) {
$version = get_cache_version();
$versioned_key = "{$key}_v{$version}";
wp_cache_set( $versioned_key, $data, 'my_group', HOUR_IN_SECONDS );
}
function invalidate_all_caches() {
// Increment version to invalidate all caches
$new_version = time();
wp_cache_set( 'cache_version', $new_version, 'global' );
}
// Pattern 4: Cache warming
add_action( 'save_post_book', 'warm_book_caches', 20 );
function warm_book_caches( $post_id ) {
// Rebuild cache immediately after invalidation
get_popular_books(); // Rebuilds transient
}
CDN Integration
// Rewrite asset URLs to CDN
add_filter( 'wp_get_attachment_url', 'cdn_rewrite_url' );
add_filter( 'wp_calculate_image_srcset', 'cdn_rewrite_srcset' );
function cdn_rewrite_url( $url ) {
$cdn_domain = 'https://cdn.example.com';
$site_url = site_url();
// Only rewrite uploads directory
if ( strpos( $url, '/wp-content/uploads/' ) !== false ) {
return str_replace( $site_url, $cdn_domain, $url );
}
return $url;
}
function cdn_rewrite_srcset( $sources ) {
if ( ! is_array( $sources ) ) {
return $sources;
}
foreach ( $sources as &$source ) {
$source['url'] = cdn_rewrite_url( $source['url'] );
}
return $sources;
}
// Purge CDN cache on content update
add_action( 'save_post', 'purge_cdn_cache' );
function purge_cdn_cache( $post_id ) {
// Example: Cloudflare API
$zone_id = 'your_zone_id';
$api_key = 'your_api_key';
$email = 'your@email.com';
$url = get_permalink( $post_id );
wp_remote_post( "https://api.cloudflare.com/client/v4/zones/{$zone_id}/purge_cache", [
'headers' => [
'X-Auth-Email' => $email,
'X-Auth-Key' => $api_key,
'Content-Type' => 'application/json',
],
'body' => json_encode([
'files' => [ $url ],
]),
]);
}
5. Advanced Database Patterns
WP_Query Optimization
// Use 'fields' parameter to limit data
$query = new WP_Query([
'post_type' => 'book',
'fields' => 'ids', // Only return IDs (faster)
]);
// Count queries
$count = new WP_Query([
'post_type' => 'book',
'posts_per_page' => -1,
'fields' => 'ids',
'no_found_rows' => true, // Skip SQL_CALC_FOUND_ROWS
'update_post_meta_cache' => false,
'update_post_term_cache' => false,
]);
// Complex meta queries with performance in mind
$query = new WP_Query([
'post_type' => 'book',
'meta_query' => [
'relation' => 'AND',
[
'key' => '_pages',
'value' => 200,
'compare' => '>',
'type' => 'NUMERIC',
],
[
'key' => '_rating',
'value' => 4,
'compare' => '>=',
'type' => 'DECIMAL',
],
],
'orderby' => 'meta_value_num',
'order' => 'DESC',
]);
Direct SQL for Complex Queries
// When WP_Query is too slow, use direct SQL
global $wpdb;
// Get books with JOIN on multiple meta keys
$results = $wpdb->get_results("
SELECT
p.ID,
p.post_title,
pm1.meta_value as isbn,
pm2.meta_value as pages,
pm3.meta_value as rating
FROM {$wpdb->posts} p
LEFT JOIN {$wpdb->postmeta} pm1 ON p.ID = pm1.post_id AND pm1.meta_key = '_isbn'
LEFT JOIN {$wpdb->postmeta} pm2 ON p.ID = pm2.post_id AND pm2.meta_key = '_pages'
LEFT JOIN {$wpdb->postmeta} pm3 ON p.ID = pm3.post_id AND pm3.meta_key = '_rating'
WHERE p.post_type = 'book'
AND p.post_status = 'publish'
AND CAST(pm2.meta_value AS UNSIGNED) > 200
ORDER BY CAST(pm3.meta_value AS DECIMAL(3,2)) DESC
LIMIT 20
");
// Use $wpdb->prepare() for dynamic values
$min_pages = 200;
$results = $wpdb->get_results( $wpdb->prepare("
SELECT p.ID, p.post_title, pm.meta_value as pages
FROM {$wpdb->posts} p
INNER JOIN {$wpdb->postmeta} pm ON p.ID = pm.post_id
WHERE p.post_type = 'book'
AND pm.meta_key = '_pages'
AND CAST(pm.meta_value AS UNSIGNED) > %d
ORDER BY p.post_date DESC
", $min_pages ) );
Database Indexing
// Add custom indexes in plugin activation
register_activation_hook( __FILE__, 'create_custom_indexes' );
function create_custom_indexes() {
global $wpdb;
// Index on post_type and post_status (common filter)
$wpdb->query("
CREATE INDEX idx_post_type_status
ON {$wpdb->posts} (post_type, post_status)
");
// Index on meta_key and meta_value for frequent lookups
$wpdb->query("
CREATE INDEX
…(truncated)