Rest.php

<?php
/**
 * Rest controller class.
 *
 * @since 0.1
 */

namespace CiviCRM_WP_REST\Controller;

class Rest extends Base {

	/**
	 * The base route.
	 *
	 * @since 0.1
	 * @var string
	 */
	protected $rest_base = 'rest';

	/**
	 * Registers routes.
	 *
	 * @since 0.1
	 */
	public function register_routes() {

		register_rest_route( $this->get_namespace(), $this->get_rest_base(), [
			[
				'methods' => \WP_REST_Server::ALLMETHODS,
				'callback' => [ $this, 'get_items' ],
				'permission_callback' => [ $this, 'permissions_check' ],
				'args' => $this->get_item_args()
			],
			'schema' => [ $this, 'get_item_schema' ]
		] );

	}

	/**
	 * Check get permission.
	 *
	 * @since 0.1
	 * @param WP_REST_Request $request
	 * @return bool
	 */
	public function permissions_check( $request ) {

		if ( ! $this->is_valid_api_key( $request ) )
			return $this->civi_rest_error( __( 'Param api_key is not valid.' ) );

		if ( ! $this->is_valid_site_key() )
			return $this->civi_rest_error( __( 'Param key is not valid.' ) );

		return true;

	}

	/**
	 * Get items.
	 *
	 * @since 0.1
	 * @param WP_REST_Request $request
	 */
	public function get_items( $request ) {

		/**
		 * Filter formatted api params.
		 *
		 * @since 0.1
		 * @param array $params
		 * @param WP_REST_Request $request
		 */
		$params = apply_filters( 'civi_wp_rest/controller/rest/api_params', $this->get_formatted_api_params( $request ), $request );

		try {

			$items = civicrm_api3( ...$params );

		} catch ( \CiviCRM_API3_Exception $e ) {

			return $this->civi_rest_error( $e->getMessage() );

		}

		if ( ! isset( $items ) || empty( $items ) )
			return rest_ensure_response( [] );

		/**
		 * Filter civi api result.
		 *
		 * @since 0.1
		 * @param array $items
		 * @param WP_REST_Request $request
		 */
		$data = apply_filters( 'civi_wp_rest/controller/rest/api_result', $items, $params, $request );

		// only collections of items, ie any action but 'getsingle'
		if ( isset( $data['values'] ) ) {

			$data['values'] = array_reduce( $items['values'] ?? $items, function( $items, $item ) use ( $request ) {

				$response = $this->prepare_item_for_response( $item, $request );

				$items[] = $this->prepare_response_for_collection( $response );

				return $items;

			}, [] );

		}

		$response = rest_ensure_response( $data );

		// check wheather we need to serve xml or json
		if ( ! in_array( 'json', array_keys( $request->get_params() ) ) ) {

			/**
			 * Adds our response holding Civi data before dispatching.
			 *
			 * @since 0.1
			 * @param WP_HTTP_Response $result Result to send to client
			 * @param WP_REST_Server $server The REST server
			 * @param WP_REST_Request $request The request
			 * @return WP_HTTP_Response $result Result to send to client
			 */
			add_filter( 'rest_post_dispatch', function( $result, $server, $request ) use ( $response ) {

				return $response;

			}, 10, 3 );

			// serve xml
			add_filter( 'rest_pre_serve_request', [ $this, 'serve_xml_response' ], 10, 4 );

		} else {

			// return json
			return $response;

		}

	}

	/**
	 * Get formatted api params.
	 *
	 * @since 0.1
	 * @param WP_REST_Resquest $request
	 * @return array $params
	 */
	public function get_formatted_api_params( $request ) {

		$args = $request->get_params();

		// destructure entity and action
		[ 'entity' => $entity, 'action' => $action ] = $args;

		// unset unnecessary args
		unset( $args['entity'], $args['action'], $args['key'], $args['api_key'] );

		if ( ! isset( $args['json'] ) || is_numeric( $args['json'] ) ) {

			$params = $args;

		} else {

			$params = is_string( $args['json'] ) ? json_decode( $args['json'], true ) : [];

		}

		// ensure check permissions is enabled
		$params['check_permissions'] = true;

		return [ $entity, $action, $params ];

	}

	/**
	 * Matches the item data to the schema.
	 *
	 * @since 0.1
	 * @param object $item
	 * @param WP_REST_Request $request
	 */
	public function prepare_item_for_response( $item, $request ) {

		return rest_ensure_response( $item );

	}

	/**
	 * Serves XML response.
	 *
	 * @since 0.1
	 * @param bool $served Whether the request has already been served
	 * @param WP_REST_Response $result
	 * @param WP_REST_Request $request
	 * @param WP_REST_Server $server
	 */
	public function serve_xml_response( $served, $result, $request, $server ) {

		// get xml from response
		$xml = $this->get_xml_formatted_data( $result->get_data() );

		// set content type header
		$server->send_header( 'Content-Type', 'text/xml' );

		echo $xml;

		return true;

	}

	/**
	 * Formats CiviCRM API result to XML.
	 *
	 * @since 0.1
	 * @param array $data The CiviCRM api result
	 * @return string $xml The formatted xml
	 */
	protected function get_xml_formatted_data( array $data ) {

		// xml document
		$xml = new \DOMDocument();

		// result set element <ResultSet>
		$result_set = $xml->createElement( 'ResultSet' );

		// xmlns:xsi attribute
		$result_set->setAttribute( 'xmlns:xsi', 'http://www.w3.org/2001/XMLSchema-instance' );

		// count attribute
		if ( isset( $data['count'] ) ) $result_set->setAttribute( 'count', $data['count'] );

		// build result from result => values
		if ( isset( $data['values'] ) ) {

			array_map( function( $item ) use ( $result_set, $xml ) {

				// result element <Result>
				$result = $xml->createElement( 'Result' );

				// format item
				$result = $this->get_xml_formatted_item( $item, $result, $xml );

				// append result to result set
				$result_set->appendChild( $result );

			}, $data['values'] );

		} else {

			// result element <Result>
			$result = $xml->createElement( 'Result' );

			// format item
			$result = $this->get_xml_formatted_item( $data, $result, $xml );

			// append result to result set
			$result_set->appendChild( $result );

		}

		// append result set
		$xml->appendChild( $result_set );

		return $xml->saveXML();

	}

	/**
	 * Formats a single api result to xml.
	 *
	 * @since 0.1
	 * @param array $item The single api result
	 * @param DOMElement $parent The parent element to append to
	 * @param DOMDocument $doc The document
	 * @return DOMElement $parent The parent element
	 */
	public function get_xml_formatted_item( array $item, \DOMElement $parent, \DOMDocument $doc ) {

		// build field => values
		array_map( function( $field, $value ) use ( $parent, $doc ) {

			// entity field element
			$element = $doc->createElement( $field );

			// handle array values
			if ( is_array( $value ) ) {

				array_map( function( $key, $val ) use ( $element, $doc ) {

					// child element, append underscore '_' otherwise createElement
					// will throw an Invalid character exception as elements cannot start with a number
					$child = $doc->createElement( '_' . $key, $val );

					// append child
					$element->appendChild( $child );

				}, array_keys( $value ), $value );

			} else {

				// assign value
				$element->nodeValue = $value;

			}

			// append element
			$parent->appendChild( $element );

		}, array_keys( $item ), $item );

		return $parent;

	}

	/**
	 * Item schema.
	 *
	 * @since 0.1
	 * @return array $schema
	 */
	public function get_item_schema() {

		return [
			'$schema' => 'http://json-schema.org/draft-04/schema#',
			'title' => 'civicrm/v3/rest',
			'description' => 'CiviCRM API3 WP rest endpoint wrapper',
			'type' => 'object',
			'required' => [ 'entity', 'action', 'params' ],
			'properties' => [
				'is_error' => [
					'type' => 'integer'
				],
				'version' => [
					'type' => 'integer'
				],
				'count' => [
					'type' => 'integer'
				],
				'values' => [
					'type' => 'array'
				]
			]
		];

	}

	/**
	 * Item arguments.
	 *
	 * @since 0.1
	 * @return array $arguments
	 */
	public function get_item_args() {

		return [
			'key' => [
				'type' => 'string',
				'required' => true,
				'validate_callback' => function( $value, $request, $key ) {

					return $this->is_valid_site_key();

				}
			],
			'api_key' => [
				'type' => 'string',
				'required' => true,
				'validate_callback' => function( $value, $request, $key ) {

					return $this->is_valid_api_key( $request );

				}
			],
			'entity' => [
				'type' => 'string',
				'required' => true,
				'validate_callback' => function( $value, $request, $key ) {

					return is_string( $value );

				}
			],
			'action' => [
				'type' => 'string',
				'required' => true,
				'validate_callback' => function( $value, $request, $key ) {

					return is_string( $value );

				}
			],
			'json' => [
				'type' => ['integer', 'string', 'array'],
				'required' => false,
				'validate_callback' => function( $value, $request, $key ) {

					return is_numeric( $value ) || is_array( $value ) || $this->is_valid_json( $value );

				}
			]
		];

	}

	/**
	 * Checks if string is a valid json.
	 *
	 * @since 0.1
	 * @param string $param
	 * @return bool
	 */
	protected function is_valid_json( $param ) {

		$param = json_decode( $param, true );

		if ( ! is_array( $param ) ) return false;

 		return ( json_last_error() == JSON_ERROR_NONE );

	}

	/**
	 * Validates the site key.
	 *
	 * @since 0.1
	 * @return bool $is_valid_site_key
	 */
	private function is_valid_site_key() {

		return \CRM_Utils_System::authenticateKey( false );

	}

	/**
	 * Validates the api key.
	 *
	 * @since 0.1
	 * @param WP_REST_Resquest $request
	 * @return bool $is_valid_api_key
	 */
	private function is_valid_api_key( $request ) {

		$api_key = $request->get_param( 'api_key' );

		if ( ! $api_key ) return false;

		$contact_id = \CRM_Core_DAO::getFieldValue( 'CRM_Contact_DAO_Contact', $api_key, 'id', 'api_key' );

		// validate contact and login
		if ( $contact_id ) {

			$wp_user = $this->get_wp_user( $contact_id );

			$this->do_user_login( $wp_user );

			return true;

		}

		return false;

	}

	/**
	 * Get WordPress user data.
	 *
	 * @since 0.1
	 * @param int $contact_id The contact id
	 * @return bool|WP_User $user The WordPress user data
	 */
	protected function get_wp_user( int $contact_id ) {

		try {

			// Get CiviCRM domain group ID from constant, if set.
			$domain_id = defined( 'CIVICRM_DOMAIN_ID' ) ? CIVICRM_DOMAIN_ID : 0;

			// If this fails, get it from config.
			if ( $domain_id === 0 ) {
				$domain_id = CRM_Core_Config::domainID();
			}

			// Call API.
			$uf_match = civicrm_api3( 'UFMatch', 'getsingle', [
				'contact_id' => $contact_id,
				'domain_id' => $domain_id,
			] );

		} catch ( \CiviCRM_API3_Exception $e ) {

			return $this->civi_rest_error( $e->getMessage() );

		}

		$wp_user = get_userdata( $uf_match['uf_id'] );

		return $wp_user;

	}

	/**
	 * Logs in the WordPress user, needed to respect CiviCRM ACL and permissions.
	 *
	 * @since 0.1
	 * @param  WP_User $user
	 */
	protected function do_user_login( \WP_User $user ) {

		if ( is_user_logged_in() ) return;

		wp_set_current_user( $user->ID, $user->user_login );

		wp_set_auth_cookie( $user->ID );

		do_action( 'wp_login', $user->user_login, $user );

	}

}