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Changeset 41744


Ignore:
Timestamp:
10/04/2017 06:44:41 PM (10 months ago)
Author:
kadamwhite
Message:

REST API: Add _fields parameter to selectively include fields in response JSON.

Allows REST API consumers to specify the specific fields needed in their application code, whitelisting those fields and omitting all others from the returned JSON response object.
This permits applications that only need for example the ID and title of posts to avoid having to transfer the entire rendered post content over the wire alongside the desired fields.
While this whitelisting has no affect on the queries run when preparing the response, it can yield significant reductions in the bandwidth required to transfer a response payload for simple applications.

Props adamsilverstein, TimothyBlynJacobs, svrooij.
Fixes #38131.

Location:
trunk
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • trunk/src/wp-includes/rest-api.php

    r41727 r41744  
    166166    add_filter( 'rest_pre_serve_request', 'rest_send_cors_headers' );
    167167    add_filter( 'rest_post_dispatch', 'rest_send_allow_header', 10, 3 );
     168    add_filter( 'rest_post_dispatch', 'rest_filter_response_fields', 10, 3 );
    168169
    169170    add_filter( 'rest_pre_dispatch', 'rest_handle_options_request', 10, 3 );
     
    629630        $response->header( 'Allow', implode( ', ', array_map( 'strtoupper', array_keys( $allowed_methods ) ) ) );
    630631    }
     632
     633    return $response;
     634}
     635
     636/**
     637 * Filter the API response to include only a white-listed set of response object fields.
     638 *
     639 * @since 4.8.0
     640 *
     641 * @param WP_REST_Response $response Current response being served.
     642 * @param WP_REST_Server   $server   ResponseHandler instance (usually WP_REST_Server).
     643 * @param WP_REST_Request  $request  The request that was used to make current response.
     644 *
     645 * @return WP_REST_Response Response to be served, trimmed down to contain a subset of fields.
     646 */
     647function rest_filter_response_fields( $response, $server, $request ) {
     648    if ( ! isset( $request['_fields'] ) || $response->is_error() ) {
     649        return $response;
     650    }
     651
     652    $data = $response->get_data();
     653
     654    $fields = is_array( $request['_fields']  ) ? $request['_fields'] : preg_split( '/[\s,]+/', $request['_fields'] );
     655
     656    if ( 0 === count( $fields ) ) {
     657        return $response;
     658    }
     659
     660    // Trim off outside whitespace from the comma delimited list.
     661    $fields = array_map( 'trim', $fields );
     662
     663    $fields_as_keyed = array_combine( $fields, array_fill( 0, count( $fields ), true ) );
     664
     665    if ( wp_is_numeric_array( $data ) ) {
     666        $new_data = array();
     667        foreach ( $data as $item ) {
     668            $new_data[] = array_intersect_key( $item, $fields_as_keyed );
     669        }
     670    } else {
     671        $new_data = array_intersect_key( $data, $fields_as_keyed );
     672    }
     673
     674    $response->set_data( $new_data );
    631675
    632676    return $response;
  • trunk/tests/phpunit/tests/rest-api.php

    r41238 r41744  
    303303
    304304        $this->assertNull( $response );
     305    }
     306
     307    /**
     308     * Ensure that result fields are not whitelisted if no request['_fields'] is present.
     309     */
     310    public function test_rest_filter_response_fields_no_request_filter() {
     311        $response = new WP_REST_Response();
     312        $response->set_data( array( 'a' => true ) );
     313        $request = array();
     314
     315        $response = rest_filter_response_fields( $response, null, $request );
     316        $this->assertEquals( array( 'a' => true ), $response->get_data() );
     317    }
     318
     319    /**
     320     * Ensure that result fields are whitelisted if request['_fields'] is present.
     321     */
     322    public function test_rest_filter_response_fields_single_field_filter() {
     323        $response = new WP_REST_Response();
     324        $response->set_data( array(
     325            'a' => 0,
     326            'b' => 1,
     327            'c' => 2,
     328        ) );
     329        $request = array(
     330            '_fields' => 'b'
     331        );
     332
     333        $response = rest_filter_response_fields( $response, null, $request );
     334        $this->assertEquals( array( 'b' => 1 ), $response->get_data() );
     335    }
     336
     337    /**
     338     * Ensure that multiple comma-separated fields may be whitelisted with request['_fields'].
     339     */
     340    public function test_rest_filter_response_fields_multi_field_filter() {
     341        $response = new WP_REST_Response();
     342        $response->set_data( array(
     343            'a' => 0,
     344            'b' => 1,
     345            'c' => 2,
     346            'd' => 3,
     347            'e' => 4,
     348            'f' => 5,
     349        ) );
     350        $request = array(
     351            '_fields' => 'b,c,e'
     352        );
     353
     354        $response = rest_filter_response_fields( $response, null, $request );
     355        $this->assertEquals( array(
     356            'b' => 1,
     357            'c' => 2,
     358            'e' => 4,
     359        ), $response->get_data() );
     360    }
     361
     362    /**
     363     * Ensure that multiple comma-separated fields may be whitelisted
     364     * with request['_fields'] using query parameter array syntax.
     365     */
     366    public function test_rest_filter_response_fields_multi_field_filter_array() {
     367        $response = new WP_REST_Response();
     368
     369        $response->set_data( array(
     370            'a' => 0,
     371            'b' => 1,
     372            'c' => 2,
     373            'd' => 3,
     374            'e' => 4,
     375            'f' => 5,
     376        ) );
     377        $request = array(
     378            '_fields' => array( 'b', 'c', 'e' )
     379        );
     380
     381        $response = rest_filter_response_fields( $response, null, $request );
     382        $this->assertEquals( array(
     383            'b' => 1,
     384            'c' => 2,
     385            'e' => 4,
     386        ), $response->get_data() );
     387    }
     388
     389    /**
     390     * Ensure that request['_fields'] whitelists apply to items in response collections.
     391     */
     392    public function test_rest_filter_response_fields_numeric_array() {
     393        $response = new WP_REST_Response();
     394        $response->set_data( array(
     395            array(
     396                'a' => 0,
     397                'b' => 1,
     398                'c' => 2,
     399            ),
     400            array(
     401                'a' => 3,
     402                'b' => 4,
     403                'c' => 5,
     404            ),
     405            array(
     406                'a' => 6,
     407                'b' => 7,
     408                'c' => 8,
     409            ),
     410        ) );
     411        $request = array(
     412            '_fields' => 'b,c'
     413        );
     414
     415        $response = rest_filter_response_fields( $response, null, $request );
     416        $this->assertEquals( array(
     417            array(
     418                'b' => 1,
     419                'c' => 2,
     420            ),
     421            array(
     422                'b' => 4,
     423                'c' => 5,
     424            ),
     425            array(
     426                'b' => 7,
     427                'c' => 8,
     428            ),
     429        ), $response->get_data() );
    305430    }
    306431
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