Route url specify the url of your call in your case its V1/product so after your store url you need to hit this url.
If suppose we are doing sum of two prodcts and my webapi.xml is as below,
<?xml version="1.0"?>
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Webapi:etc/webapi.xsd">
<route url="/V1/calculator/add/:num1/:num2" method="GET">
<service class="Test\Calculator\Api\CalculatorInterface" method="add"/>
<resources>
<resource ref="anonymous"/>
</resources>
</route>
</routes>
I will hit url,http://10.16.16.190/magentoce27/index.php/rest/V1/calculator/add/1/2
where route url matches url and paramerters as above,
Now, service class defines API Interface for the purpose of method declaration for example,
<?php
namespace Test\Calculator\Api;
interface CalculatorInterface
{
/**
* Add two numbers.
*
* @param int $num1
* @param int $num2
* @return int
*/
public function add($num1, $num2);
}
?>
If you get a token with a customer username/password, you can only access API methods with <resource ref="self"></resource> or <resource ref="anonymous"></resource>. The <resource ref="anonymous"></resource> methods can be called without any authorization.
