```

FastAPI will use the return type annotation to perform:

* Data validation
* Automatic documentation
    * It could power automatic client generators
* **Data filtering**

Before this version it was only supported via the `response_model` parameter.

Read more about it in the new docs: [Response Model - Return Type](https://fastapi.tiangolo.com/tutorial/response-model/).

### Docs

    # TODO: remove after upgrading python-jose to a version that explicitly supports Python 3.12
    # also, if it won't receive an update, consider replacing python-jose with some alternative
    # related issues:
    #   - https://github.com/mpdavis/python-jose/issues/332
    #   - https://github.com/mpdavis/python-jose/issues/334

        dep -->> handler: Auto forward exception
    end
    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> dep: Raise other exception
    end
    Note over dep: After yield

- ক্রিয়াশীল API নির্দেশিকা নথিটি স্বয়ংক্রিয়ভাবে উন্নীত হযে যাবে, নতুন বডি সহ:

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-03-swagger-02.png)

- "Try it out" বাটনে চাপুন, এটি আপনাকে পেরামিটারগুলো পূরণ করতে এবং API এর সাথে সরাসরি ক্রিয়া-কলাপ করতে দিবে:

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-04-swagger-03.png)

    ```Python hl_lines="8-11"
    {!> ../../../docs_src/dependencies/tutorial001.py!}
    ```

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

You can think of it as a *path operation function* without the "decorator" (without the `@app.get("/some-path")`).

And it can return anything you want.

In this case, this dependency expects:

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*:

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.
* And it could also have a declaration of the response it should return, e.g. `response_model=InvoiceEventReceived`.

```Python hl_lines="16-18  21-22  28-32"

By default it will listen on the IP address `127.0.0.1`, which is the IP for your machine to communicate with itself alone (`localhost`).

## `fastapi run`

When you run `fastapi run`, it will run on production mode by default.

It will have **auto-reload disabled** by default.

### Check the code

* Check and read the code, see if it makes sense, **run it locally** and see if it actually solves the problem.

* Then **comment** saying that you did that, that's how I will know you really checked it.

!!! info
    Unfortunately, I can't simply trust PRs that just have several approvals.

    'email': '******@****.***',
    'full_name': None,
}
```

#### Unwrapping a `dict`

If we take a `dict` like `user_dict` and pass it to a function (or class) with `**user_dict`, Python will "unwrap" it. It will pass the keys and values of the `user_dict` directly as key-value arguments.

So, continuing with the `user_dict` from above, writing:

```Python
UserInDB(**user_dict)
```

would result in something equivalent to:

## Documenting webhooks with **FastAPI** and OpenAPI

With **FastAPI**, using OpenAPI, you can define the names of these webhooks, the types of HTTP operations that your app can send (e.g. `POST`, `PUT`, etc.) and the request **bodies** that your app would send.