protected function make_validation() {
		$data   = array();
		$params = array(
			'app_name',
			'user_id',
			'return_url',
			'callback_url',
			'scope',
		);

		foreach ( $params as $param ) {
			if ( empty( $_REQUEST[ $param ] ) ) { // WPCS: input var ok, CSRF ok.
				/* translators: %s: parameter */
				throw new Exception( sprintf( __( 'Missing parameter %s', 'woocommerce' ), $param ) );
			}

			$data[ $param ] = wp_unslash( $_REQUEST[ $param ] ); // WPCS: input var ok, CSRF ok, sanitization ok.
		}

		if ( ! in_array( $data['scope'], array( 'read', 'write', 'read_write' ), true ) ) {
			/* translators: %s: scope */
			throw new Exception( sprintf( __( 'Invalid scope %s', 'woocommerce' ), wc_clean( $data['scope'] ) ) );
		}

		foreach ( array( 'return_url', 'callback_url' ) as $param ) {
			$param = $this->get_formatted_url( $data[ $param ] );

			if ( false === filter_var( $param, FILTER_VALIDATE_URL ) ) {
				/* translators: %s: url */
				throw new Exception( sprintf( __( 'The %s is not a valid URL', 'woocommerce' ), $param ) );
			}
		}

		$callback_url = $this->get_formatted_url( $data['callback_url'] );

		if ( 0 !== stripos( $callback_url, 'https://' ) ) {
			throw new Exception( __( 'The callback_url needs to be over SSL', 'woocommerce' ) );
		}
	}