participant dep as Dep with yield
participant operation as Path Operation
participant tasks as Background tasks

    Note over client,tasks: Can raise exception for dependency, handled after response is sent
    Note over client,operation: Can raise HTTPException and can change the response
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise
        dep -->> handler: Raise HTTPException

## Future

By this point, it's already clear that **FastAPI** with its ideas is being useful for many people.

It is being chosen over previous alternatives for suiting many use cases better.

Many developers and teams already depend on **FastAPI** for their projects (including me and my team).

But still, there are many improvements and features to come.

This will be especially useful when you use it in a **large code base** where you use **the same dependencies** over and over again in **many *path operations***.

## To `async` or not to `async`

As dependencies will also be called by **FastAPI** (the same as your *path operation functions*), the same rules apply while defining your functions.

    ```

    </div>

=== "Hypercorn"

    <div class="termy">

    ```console
    $ hypercorn main:app --bind 0.0.0.0:80

    Running on 0.0.0.0:8080 over http (CTRL + C to quit)
    ```

    </div>

!!! warning "Achtung"
    Denken Sie daran, die Option `--reload` zu entfernen, wenn Sie diese verwendet haben.

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="12"
    {!> ../../../docs_src/request_files/tutorial001.py!}
    ```

Using `UploadFile` has several advantages over `bytes`:

* You don't have to use `File()` in the default value of the parameter.
* It uses a "spooled" file:
    * A file stored in memory up to a maximum size limit, and after passing this limit it will be stored in disk.

participant dep as Abhängigkeit mit yield
participant operation as Pfadoperation
participant tasks as Hintergrundtasks

    Note over client,operation: Kann Exceptions auslösen, inklusive HTTPException
    client ->> dep: Startet den Request
    Note over dep: Führt den Code bis zum yield aus
    opt Löst Exception aus
        dep -->> handler: Löst Exception aus
        handler -->> client: HTTP-Error-Response

{!../../../docs_src/custom_response/tutorial007.py!}
```

#### Using `StreamingResponse` with file-like objects

If you have a file-like object (e.g. the object returned by `open()`), you can create a generator function to iterate over that file-like object.

That way, you don't have to read it all first in memory, and you can pass that generator function to the `StreamingResponse`, and return it.

    ```

    </div>

=== "Hypercorn"

    <div class="termy">

    ```console
    $ hypercorn main:app --bind 0.0.0.0:80

    Running on 0.0.0.0:8080 over http (CTRL + C to quit)
    ```

    </div>

!!! warning "Предупреждение"

    Не забудьте удалить опцию `--reload`, если ранее пользовались ею.

    ```

    </div>


=== "Hypercorn"

    <div class="termy">

    ```console
    $ hypercorn main:app --bind 0.0.0.0:80

    Running on 0.0.0.0:8080 over http (CTRL + C to quit)
    ```

    </div>

!!! warning
     如果您正在使用`--reload`选项，请记住删除它。

     `--reload` 选项消耗更多资源，并且更不稳定。

     它在**开发**期间有很大帮助，但您**不应该**在**生产环境**中使用它。

## Hypercorn with Trio

---

"_I’m over the moon excited about **FastAPI**. It’s so fun!_"