Welcome to tutorial #4. Today we are diving deep into custom WordPress development techniques that will help you build faster, more secure, and highly maintainable solutions for your clients.
Secure Database Queries with $wpdb
Always use the global `$wpdb` object for custom queries. To prevent SQL injection, never pass raw user input into a query. Always use the `prepare` method to safely insert variables.
global $wpdb;
$user_id = 5;
$results = $wpdb->get_results( $wpdb->prepare(
"SELECT * FROM {$wpdb->prefix}custom_table WHERE user_id = %d",
$user_id
) );Best Practices for Custom Code
When writing custom code for WordPress, always use the appropriate hooks instead of modifying core files. Use a site-specific functionality plugin instead of adding code to your theme’s `functions.php` file, so that your customizations survive theme updates. Always comment your code and use descriptive function names to make it maintainable by other developers.
Debugging WordPress Code Effectively
Do not develop in the dark. Enable WordPress debug mode by setting `WP_DEBUG` to true in your `wp-config.php` file during development. This will display PHP errors and notices directly on the screen or in a log file, helping you catch bugs early. Never leave debug mode enabled on a live production site, as it can expose sensitive information.
Security Considerations in Custom Dev
Always sanitize data on input and escape data on output. Use WordPress functions like `sanitize_text_field` before saving data to the database, and `esc_html` or `esc_attr` when echoing data in HTML. This protects your site from Cross-Site Scripting (XSS) and SQL injection attacks, ensuring your custom solutions are secure.