How to make a parser in Symfony 3 correctly?

Question

symfony

I'm just starting to learn Symphony and I don't really understand how to properly implement the functionality.
For example, there is a task: to parse by reference and generate objects based on this data.
I made an entity whose objects should be generated; I'm going to use the DomCrawler component for parsing; I will make the parser itself a service; the service code will be called by the user's action on the site. Correct way of thinking?