WordPress at a glance
function is not described

WP_REST_Revisions_Controller::get_items() public WP 4.7.0

Gets a collection of revisions.

{} It's a method of the class: WP_REST_Revisions_Controller{}

Hooks from the method
Return

WP_REST_Response/WP_Error. Response object on success, or WP_Error object on failure.

Usage

$WP_REST_Revisions_Controller = new WP_REST_Revisions_Controller();
$WP_REST_Revisions_Controller->get_items( $request );
$request(WP_REST_Request) (required)
Full details about the request.

Changelog

Since 4.7.0 Introduced.

Code of WP_REST_Revisions_Controller::get_items() WP 5.5.1

<?php
public function get_items( $request ) {
	$parent = $this->get_parent( $request['parent'] );
	if ( is_wp_error( $parent ) ) {
		return $parent;
	}

	// Ensure a search string is set in case the orderby is set to 'relevance'.
	if ( ! empty( $request['orderby'] ) && 'relevance' === $request['orderby'] && empty( $request['search'] ) ) {
		return new WP_Error(
			'rest_no_search_term_defined',
			__( 'You need to define a search term to order by relevance.' ),
			array( 'status' => 400 )
		);
	}

	// Ensure an include parameter is set in case the orderby is set to 'include'.
	if ( ! empty( $request['orderby'] ) && 'include' === $request['orderby'] && empty( $request['include'] ) ) {
		return new WP_Error(
			'rest_orderby_include_missing_include',
			__( 'You need to define an include parameter to order by include.' ),
			array( 'status' => 400 )
		);
	}

	if ( wp_revisions_enabled( $parent ) ) {
		$registered = $this->get_collection_params();
		$args       = array(
			'post_parent'      => $parent->ID,
			'post_type'        => 'revision',
			'post_status'      => 'inherit',
			'posts_per_page'   => -1,
			'orderby'          => 'date ID',
			'order'            => 'DESC',
			'suppress_filters' => true,
		);

		$parameter_mappings = array(
			'exclude'  => 'post__not_in',
			'include'  => 'post__in',
			'offset'   => 'offset',
			'order'    => 'order',
			'orderby'  => 'orderby',
			'page'     => 'paged',
			'per_page' => 'posts_per_page',
			'search'   => 's',
		);

		foreach ( $parameter_mappings as $api_param => $wp_param ) {
			if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {
				$args[ $wp_param ] = $request[ $api_param ];
			}
		}

		// For backward-compatibility, 'date' needs to resolve to 'date ID'.
		if ( isset( $args['orderby'] ) && 'date' === $args['orderby'] ) {
			$args['orderby'] = 'date ID';
		}

		/** This filter is documented in wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php */
		$args       = apply_filters( 'rest_revision_query', $args, $request );
		$query_args = $this->prepare_items_query( $args, $request );

		$revisions_query = new WP_Query();
		$revisions       = $revisions_query->query( $query_args );
		$offset          = isset( $query_args['offset'] ) ? (int) $query_args['offset'] : 0;
		$page            = (int) $query_args['paged'];
		$total_revisions = $revisions_query->found_posts;

		if ( $total_revisions < 1 ) {
			// Out-of-bounds, run the query again without LIMIT for total count.
			unset( $query_args['paged'], $query_args['offset'] );

			$count_query = new WP_Query();
			$count_query->query( $query_args );

			$total_revisions = $count_query->found_posts;
		}

		if ( $revisions_query->query_vars['posts_per_page'] > 0 ) {
			$max_pages = ceil( $total_revisions / (int) $revisions_query->query_vars['posts_per_page'] );
		} else {
			$max_pages = $total_revisions > 0 ? 1 : 0;
		}

		if ( $total_revisions > 0 ) {
			if ( $offset >= $total_revisions ) {
				return new WP_Error(
					'rest_revision_invalid_offset_number',
					__( 'The offset number requested is larger than or equal to the number of available revisions.' ),
					array( 'status' => 400 )
				);
			} elseif ( ! $offset && $page > $max_pages ) {
				return new WP_Error(
					'rest_revision_invalid_page_number',
					__( 'The page number requested is larger than the number of pages available.' ),
					array( 'status' => 400 )
				);
			}
		}
	} else {
		$revisions       = array();
		$total_revisions = 0;
		$max_pages       = 0;
		$page            = (int) $request['page'];
	}

	$response = array();

	foreach ( $revisions as $revision ) {
		$data       = $this->prepare_item_for_response( $revision, $request );
		$response[] = $this->prepare_response_for_collection( $data );
	}

	$response = rest_ensure_response( $response );

	$response->header( 'X-WP-Total', (int) $total_revisions );
	$response->header( 'X-WP-TotalPages', (int) $max_pages );

	$request_params = $request->get_query_params();
	$base           = add_query_arg( urlencode_deep( $request_params ), rest_url( sprintf( '%s/%s/%d/%s', $this->namespace, $this->parent_base, $request['parent'], $this->rest_base ) ) );

	if ( $page > 1 ) {
		$prev_page = $page - 1;

		if ( $prev_page > $max_pages ) {
			$prev_page = $max_pages;
		}

		$prev_link = add_query_arg( 'page', $prev_page, $base );
		$response->link_header( 'prev', $prev_link );
	}
	if ( $max_pages > $page ) {
		$next_page = $page + 1;
		$next_link = add_query_arg( 'page', $next_page, $base );

		$response->link_header( 'next', $next_link );
	}

	return $response;
}