Source

File: wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php

public function get_collection_params() {
		$query_params = parent::get_collection_params();

		$query_params['context']['default'] = 'view';

		$query_params['after'] = array(
			'description' => __( 'Limit response to posts published after a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		if ( post_type_supports( $this->post_type, 'author' ) ) {
			$query_params['author']         = array(
				'description' => __( 'Limit result set to posts assigned to specific authors.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
			$query_params['author_exclude'] = array(
				'description' => __( 'Ensure result set excludes posts assigned to specific authors.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
		}

		$query_params['before'] = array(
			'description' => __( 'Limit response to posts published before a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		$query_params['exclude'] = array(
			'description' => __( 'Ensure result set excludes specific IDs.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'integer',
			),
			'default'     => array(),
		);

		$query_params['include'] = array(
			'description' => __( 'Limit result set to specific IDs.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'integer',
			),
			'default'     => array(),
		);

		if ( 'page' === $this->post_type || post_type_supports( $this->post_type, 'page-attributes' ) ) {
			$query_params['menu_order'] = array(
				'description' => __( 'Limit result set to posts with a specific menu_order value.' ),
				'type'        => 'integer',
			);
		}

		$query_params['offset'] = array(
			'description' => __( 'Offset the result set by a specific number of items.' ),
			'type'        => 'integer',
		);

		$query_params['order'] = array(
			'description' => __( 'Order sort attribute ascending or descending.' ),
			'type'        => 'string',
			'default'     => 'desc',
			'enum'        => array( 'asc', 'desc' ),
		);

		$query_params['orderby'] = array(
			'description' => __( 'Sort collection by object attribute.' ),
			'type'        => 'string',
			'default'     => 'date',
			'enum'        => array(
				'author',
				'date',
				'id',
				'include',
				'modified',
				'parent',
				'relevance',
				'slug',
				'include_slugs',
				'title',
			),
		);

		if ( 'page' === $this->post_type || post_type_supports( $this->post_type, 'page-attributes' ) ) {
			$query_params['orderby']['enum'][] = 'menu_order';
		}

		$post_type = get_post_type_object( $this->post_type );

		if ( $post_type->hierarchical || 'attachment' === $this->post_type ) {
			$query_params['parent']         = array(
				'description' => __( 'Limit result set to items with particular parent IDs.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
			$query_params['parent_exclude'] = array(
				'description' => __( 'Limit result set to all items except those of a particular parent ID.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
		}

		$query_params['slug'] = array(
			'description'       => __( 'Limit result set to posts with one or more specific slugs.' ),
			'type'              => 'array',
			'items'             => array(
				'type' => 'string',
			),
			'sanitize_callback' => 'wp_parse_slug_list',
		);

		$query_params['status'] = array(
			'default'           => 'publish',
			'description'       => __( 'Limit result set to posts assigned one or more statuses.' ),
			'type'              => 'array',
			'items'             => array(
				'enum' => array_merge( array_keys( get_post_stati() ), array( 'any' ) ),
				'type' => 'string',
			),
			'sanitize_callback' => array( $this, 'sanitize_post_statuses' ),
		);

		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

		if ( ! empty( $taxonomies ) ) {
			$query_params['tax_relation'] = array(
				'description' => __( 'Limit result set based on relationship between multiple taxonomies.' ),
				'type'        => 'string',
				'enum'        => array( 'AND', 'OR' ),
			);
		}

		foreach ( $taxonomies as $taxonomy ) {
			$base = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;

			$query_params[ $base ] = array(
				/* translators: %s: Taxonomy name. */
				'description' => sprintf( __( 'Limit result set to all items that have the specified term assigned in the %s taxonomy.' ), $base ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);

			$query_params[ $base . '_exclude' ] = array(
				/* translators: %s: Taxonomy name. */
				'description' => sprintf( __( 'Limit result set to all items except those that have the specified term assigned in the %s taxonomy.' ), $base ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
		}

		if ( 'post' === $this->post_type ) {
			$query_params['sticky'] = array(
				'description' => __( 'Limit result set to items that are sticky.' ),
				'type'        => 'boolean',
			);
		}

		/**
		 * Filter collection parameters for the posts controller.
		 *
		 * The dynamic part of the filter `$this->post_type` refers to the post
		 * type slug for the controller.
		 *
		 * This filter registers the collection parameter, but does not map the
		 * collection parameter to an internal WP_Query parameter. Use the
		 * `rest_{$this->post_type}_query` filter to set WP_Query parameters.
		 *
		 * @since 4.7.0
		 *
		 * @param array        $query_params JSON Schema-formatted collection parameters.
		 * @param WP_Post_Type $post_type    Post type object.
		 */
		return apply_filters( "rest_{$this->post_type}_collection_params", $query_params, $post_type );
	}