I've made this on one plugin

rewrite_example.php

<?php

class Config {
	public function __construct() {
		add_action( 'init', array( $this, '_wpSoapGetEndPoint' ) );
		add_action( 'template_redirect', array( $this, '_wpSoapGetEndPointData' ) );
	}

	/**
	 * Idnetify Soap Request Endpoint and Perform URL Pattern Rewrite Rules Validation Checks
	 * @since   1.0
	 */
	public function _wpSoapGetEndPoint() {
		/**
		 * @var \WP_Rewrite $wp_rewrite
		 */
		add_rewrite_tag( '%api%', 'soap' );
		add_rewrite_tag( '%soap_action%', 'listening' );
		add_rewrite_rule( '^soap-([a-zA-Z0-1]+)', 'index.php?api=soap&soap_action=$matches[1]', 'top' );
		flush_rewrite_rules();
	}

	/**
	 * Idnetify Soap Request Endpoint and Handle with Soap Server Handle
	 * @since   1.0
	 */
	public function _wpSoapGetEndPointData() {

		//Remove whitespaces if any
		ob_clean();

		/**
		 * Globals to get wp_query
		 * @var \WP_Query $wp_query
		 */
		global $wp_query;

		//Get query params and identify valid endpoint
		$api         = $wp_query->get( 'api' );
		$soap_action = $wp_query->get( 'soap_action' );

		if ( $api == 'soap' && ! empty( $soap_action ) ) {
			Web::call( $soap_action );
			$error = error_get_last();
			if ( ! empty( $error ) ) {
				Log::error( $error['message'] . ' at ' . $error['file'] . ':' . $error['line'] );
			}
			exit;
		}
	}
}