Hook & Filter Architecture

Overview

The wordpress repository utilizes the standard WordPress event-driven architecture, allowing developers to extend and modify core functionality without altering the base source code. This is achieved through two primary mechanisms: Actions and Filters.

• Actions (Hooks): Allow you to trigger custom code at specific points during the execution cycle.
• Filters: Allow you to intercept and modify data before it is processed or rendered.

Action Hooks

Actions are used to perform tasks (like logging, sending emails, or injecting scripts) when a specific event occurs.

Usage

To hook into an action, use the add_action() function.

/**
 * Example: Triggering a custom function during project initialization.
 */
add_action('ua_init_mvp_feature', 'handle_custom_initialization', 10, 1);

function handle_custom_initialization($feature_data) {
    // Your custom logic here
    error_log('Feature initialized: ' . $feature_data['name']);
}

Common Action Hooks

| Hook Name | Description | Parameters | | :--- | :--- | :--- | | ua_before_context_render | Fires before the main MVP context is rendered. | (array) $context_params | | ua_after_module_load | Fires immediately after a specific module is loaded. | (string) $module_id | | ua_on_data_sync | Fires when data synchronization completes. | (bool) $is_success |

Filter Hooks

Filters are used to manipulate variables or data structures. Your callback function must return a value.

Usage

To modify data using a filter, use the add_filter() function.

/**
 * Example: Modifying the default configuration array.
 */
add_filter('ua_base_configuration', 'customize_mvp_config', 10, 1);

function customize_mvp_config($config) {
    $config['debug_mode'] = true;
    $config['api_timeout'] = 30;
    
    return $config; // Always return the filtered value
}

Common Filter Hooks

| Hook Name | Description | Expected Return Type | | :--- | :--- | :--- | | ua_filter_output_data | Modifies the final array before output. | array | | ua_content_template_path | Overrides the file path for the content template. | string | | ua_is_feature_enabled | Dynamically enables/disables features. | boolean |

Technical Specifications

Input Parameters

When hooking into these interfaces, the following standard parameters apply to both add_action() and add_filter():

1. Tag (string): The name of the hook to join.
2. Callback (callable): The function to be run.
3. Priority (int): (Optional) Used to specify the order in which the functions associated with a particular action are executed. Lower numbers = earlier execution. Default is 10.
4. Accepted Arguments (int): (Optional) The number of arguments the function accepts. Default is 1.

Best Practices

• Prefixing: All custom hooks in this repository are prefixed with ua_ to prevent collisions with WordPress core or other plugins.
• Return Types: When using filters, ensure the returned data type matches the input data type to prevent runtime errors in the core logic.
• Anonymous Functions: While supported, using named functions or class methods is recommended for better compatibility with remove_action() or remove_filter() calls.

Internal Event Dispatchers

Note: These functions are used internally by the core to trigger the hooks listed above. Developers should use the public add_action and add_filter interfaces instead.

• do_action(): Invokes the callbacks attached to an action hook.
• apply_filters(): Invokes the callbacks attached to a filter hook and returns the modified value.