Find WP Rest Route Callback by an URL

rest-route-finder.php

<?php
/**
 * Plugin Name: REST Routes CLI
 * Version: 0.0.1
 */

defined( 'ABSPATH' ) || exit;

function routes_match( $args ) {
	$routes = rest_get_server()->get_routes();


	if ( ! isset( $args[0] ) ) {
		echo "Missing required argument: path\n";
		echo "Example: wp find-rest-route :path\n";
		exit;
	}

	if ( false === strpos( $args[0], 'wp-json') ) {
		echo "Invalid REST API endpoint. A valid endpoint must contain 'wp-json'\n";
		exit;
	}

	$path = parse_url( $args[0] )[ 'path' ];
	$path = str_replace( '/wp-json', '', $path );

	// Remove escape char
	$path = trim( $path, "\\" );

	foreach ( $routes as $route => $handlers ) {
		$match = preg_match( '@^' . $route . '$@i', $path );

		if ( ! $match ) {
			continue;
		}

		$methods = [];

		foreach ( $handlers as $handler ) {
			if ( is_object( $handler['callback'][0] ) ) {
				$callback = get_class( $handler['callback'][0] ). '::' .$handler['callback'][1];
			} else {
				$callback = $handler['callback'][0];
			}

			$methods[ implode( ',', array_keys( $handler['methods'] ) ) ] = $callback;
		}

		print_r($methods);
	}
}

add_action( 'plugins_loaded', function() {
	if ( class_exists( 'WP_CLI' ) ) {
		WP_CLI::add_command( 'routes match', 'routes_match' );
	}
}, 999 );

1. Install WP CLI
2. Download this gist and save it in your wp-content/plugins directory.
3. Activate the plugin
4. Go to your local directory and run wp help and confirm find-rest-route is listed under SUBCOMMANDS
5. Run wp find-rest-route :rest-api-endpoint-url

Example

Endpoint: http://woodev.local/wp-json/wc-admin/onboarding/tasks?_locale=user

Usage: wp find-rest-route http://woodev.local/wp-json/wc-admin/onboarding/tasks?_locale=user

OUTPUT

Array
(
    [GET] => Automattic\WooCommerce\Admin\API\OnboardingTasks::get_tasks
    [POST] => Automattic\WooCommerce\Admin\API\OnboardingTasks::get_tasks
)