Handling request parameters
The main goal of a representational state transfer (REST) API is to provide a structured way to interact with data. As such, it’s crucial for the end user to send some information to tailor the response they need, such as path parameters, query parameters, body payloads, headers, and so on.
Web frameworks usually ask you to manipulate a request object to retrieve the parts you are interested in and manually apply validation to handle them. However, that’s not necessary with FastAPI! Indeed, it allows you to define all of your parameters declaratively. Then, it’ll automatically retrieve them in the request and apply validation based on the type hints. This is why we introduced type hinting in Chapter 2, Python Programming Specificities: it’s used by FastAPI to perform data validation!
Next, we’ll explore how you can use this feature to retrieve and validate this input data from different parts of the request.
