Automattic / jetpack

		// are known to work with signature verification.  A different method

		// can be passed to the WP REST API via the '?_method=' parameter if

		// needed.

		if ( $_SERVER['REQUEST_METHOD'] !== 'GET' && $_SERVER['REQUEST_METHOD'] !== 'POST' ) {

			return new WP_Error(

				'rest_invalid_request',

				'This request method is not supported.',

				array( 'status' => 400 )

			);

		}

		if ( $_SERVER['REQUEST_METHOD'] !== 'POST' && ! empty( $this->HTTP_RAW_POST_DATA ) ) {

			return new WP_Error(

				'rest_invalid_request',

				array( 'status' => 400 )

			);

		}

		if (

			isset( $_SERVER['CONTENT_TYPE'] ) &&

			$_SERVER['CONTENT_TYPE'] !== 'application/x-www-form-urlencoded' &&

			$_SERVER['CONTENT_TYPE'] !== 'application/json'

		) {

			return new WP_Error(

				'rest_invalid_request',

				'This Content-Type is not supported.',

				array( 'status' => 400 )

			);

		}

		$verified = $this->verify_xml_rpc_signature();