How do I add an id/parameter to a frontend route?

Question

I want to add an "id"/"parameter" to a front-end route in the following way:

store.example.com/blogpost/view/**213**

where 213 is the parameter I want to pass.

I have been looking at the Magento 2 dev docs, but I can't seem to find anything regarding adding this parameter.

And I can't seem to find anything that adds the "id" to the existing product route (catalog/product/view/id/:id) in magento/module-catalog. I'm probably missing something.

etc/frontend/routes.xml

<?xml version="1.0"?>

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:App/etc/routes.xsd">
    <router id="standard">
        <route id="blogpost" frontName="blogpost">
            <module name="MyModule_BlogPost" />
        </route>
    </router>
</config>

Controller/View/Index.php

<?php

namespace MyModule\BlogPost\Controller\Search;

class Index extends \Magento\Framework\App\Action\Action
{
    public function execute()
    {
        // This only includes url query parameters ?param1=123&param2=active
        $params = $this->getRequest->getParams();

        // But I'd like to do this like the catalog/product/view/id/:id route ...
    }
}

Do I need to make a custom router for this, or is there another way?