概述
在编写端点时，使用控制器类来处理端点的功能可能会有所帮助。控制器类将提供与API交互的标准方法，也将提供与API交互的更可维护的方法。WordPress当前的最低PHP版本为5.2，如果您正在开发WordPress生态系统将使用的端点，则应考虑支持WordPress的最低要求。
PHP 5.2没有内置的命名区。这意味着您声明的每个函数都将在全球范围内。如果您决定使用公共函数名称作为端点get_items()另一个插件还注册了功能的功能，PHP将因致命错误而失败。这是因为功能get_items()被宣布两次。通过包裹我们的终点，我们可以避免这些命名冲突，并且具有与API互动的一致方法。
控制器
控制器通常会做一件事；他们接收输入并生成输出。对于WordPress REST API，我们的控制器将处理请求输入为WP_REST_Request对象并生成响应输出作为WP_REST_Response对象。让我们看一个示例控制器类：
class My_REST_Posts_Controller {
// Here initialize our namespace and resource name.
public function __construct() {
$this->namespace = '/my-namespace/v1';
$this->resource_name = 'posts';
}
// Register our routes.
public function register_routes() {
register_rest_route( $this->namespace, '/' . $this->resource_name, array(
// Here we register the readable endpoint for collections.
array(
'methods' => 'GET',
'callback' => array( $this, 'get_items' ),
'permission_callback' => array( $this, 'get_items_permissions_check' ),
),
// Register our schema callback.
'schema' => array( $this, 'get_item_schema' ),
) );
register_rest_route( $this->namespace, '/' . $this->resource_name . '/(?P<id>[\d]+)', array(
// Notice how we are registering multiple endpoints the 'schema' equates to an OPTIONS request.
array(
'methods' => 'GET',
'callback' => array( $this, 'get_item' ),
'permission_callback' => array( $this, 'get_item_permissions_check' ),
),
// Register our schema callback.
'schema' => array( $this, 'get_item_schema' ),
) );
}
/**
* Check permissions for the posts.
*
* @param WP_REST_Request $request Current request.
*/
public function get_items_permissions_check( $request ) {
if ( ! current_user_can( 'read' ) ) {
return new WP_Error( 'rest_forbidden', esc_html__( 'You cannot view the post resource.' ), array( 'status' => $this->authorization_status_code() ) );
}
return true;
}
/**
* Grabs the five most recent posts and outputs them as a rest response.
*
* @param WP_REST_Request $request Current request.
*/
public function get_items( $request ) {
$args = array(
'post_per_page' => 5,
);
$posts = get_posts( $args );
$data = array();
if ( empty( $posts ) ) {
return rest_ensure_response( $data );
}
foreach ( $posts as $post ) {
$response = $this->prepare_item_for_response( $post, $request );
$data[] = $this->prepare_response_for_collection( $response );
}
// Return all of our comment response data.
return rest_ensure_response( $data );
}
/**
* Check permissions for the posts.
*
* @param WP_REST_Request $request Current request.
*/
public function get_item_permissions_check( $request ) {
if ( ! current_user_can( 'read' ) ) {
return new WP_Error( 'rest_forbidden', esc_html__( 'You cannot view the post resource.' ), array( 'status' => $this->authorization_status_code() ) );
}
return true;
}
/**
* Grabs the five most recent posts and outputs them as a rest response.
*
* @param WP_REST_Request $request Current request.
*/
public function get_item( $request ) {
$id = (int) $request['id'];
$post = get_post( $id );
if ( empty( $post ) ) {
return rest_ensure_response( array() );
}
$response = prepare_item_for_response( $post );
// Return all of our post response data.
return $response;
}
/**
* Matches the post data to the schema we want.
*
* @param WP_Post $post The comment object whose response is being prepared.
*/
public function prepare_item_for_response( $post, $request ) {
$post_data = array();
$schema = $this->get_item_schema( $request );
// We are also renaming the fields to more understandable names.
if ( isset( $schema['properties']['id'] ) ) {
$post_data['id'] = (int) $post->ID;
}
if ( isset( $schema['properties']['content'] ) ) {
$post_data['content'] = apply_filters( 'the_content', $post->post_content, $post );
}
return rest_ensure_response( $post_data );
}
/**
* Prepare a response for inserting into a collection of responses.
*
* This is copied from WP_REST_Controller class in the WP REST API v2 plugin.
*
* @param WP_REST_Response $response Response object.
* @return array Response data, ready for insertion into collection data.
*/
public function prepare_response_for_collection( $response ) {
if ( ! ( $response instanceof WP_REST_Response ) ) {
return $response;
}
$data = (array) $response->get_data();
$server = rest_get_server();
if ( method_exists( $server, 'get_compact_response_links' ) ) {
$links = call_user_func( array( $server, 'get_compact_response_links' ), $response );
} else {
$links = call_user_func( array( $server, 'get_response_links' ), $response );
}
if ( ! empty( $links ) ) {
$data['_links'] = $links;
}
return $data;
}
/**
* Get our sample schema for a post.
*
* @param WP_REST_Request $request Current request.
*/
public function get_item_schema( $request ) {
$schema = array(
// This tells the spec of JSON Schema we are using which is draft 4.
'$schema' => 'http://json-schema.org/draft-04/schema#',
// The title property marks the identity of the resource.
'title' => 'post',
'type' => 'object',
// In JSON Schema you can specify object properties in the properties attribute.
'properties' => array(
'id' => array(
'description' => esc_html__( 'Unique identifier for the object.', 'my-textdomain' ),
'type' => 'integer',
'context' => array( 'view', 'edit', 'embed' ),
'readonly' => true,
),
'content' => array(
'description' => esc_html__( 'The content for the object.', 'my-textdomain' ),
'type' => 'string',
),
),
);
return $schema;
}
// Sets up the proper HTTP status code for authorization.
public function authorization_status_code() {
$status = 401;
if ( is_user_logged_in() ) {
$status = 403;
}
return $status;
}
}
// Function to register our new routes from the controller.
function prefix_register_my_rest_routes() {
$controller = new My_REST_Posts_Controller();
$controller->register_routes();
}
add_action( 'rest_api_init', 'prefix_register_my_rest_routes' );概述与未来
在开发终点时，控制器类别为我们解决了两个大问题。缺乏命名领域和一致的结构。重要的是要注意，您不应滥用终点的继承。例如：如果您为帖子端点写了一个控制器类，例如上述示例，并且也希望支持自定义帖子类型，则应 不是 扩展您的My_REST_Posts_Controller像这样class My_CPT_REST_Controller extends My_REST_Posts_Controller。
相反，您应该创建一个完全独立的控制器类，或者使My_REST_Posts_Controller处理所有可用的帖子类型。当您开始沿着继承的黑暗鸿沟往下走时，重要的是要了解，如果父母必须在任何时候进行更改，并且子类取决于它们，那么您将有一个重大的头痛。在大多数情况下，您将需要创建一个基本控制器类作为一个interface或者abstract class，您的每个端点控制器都可以实现或扩展。这abstract classWP REST API团队正在采取方法，以将其纳入核心WP_REST_Controller班级。
当前，“核心端点”支持帖子，帖子类型，帖子状态，修订，分类法，条款，用户，注释和附件/媒体资源正在功能插件中开发，希望在某个时候将其移至WordPress核心。插件中是提出的WP_REST_Controller可以用于为您的端点构建自己的控制器的类。WP_REST_Controller具有许多优势和一种为API创建端点的一致方法。