If you understood all this, you already know how those utility tools for security work underneath.

///

## Dependencies with `yield`, `HTTPException`, `except` and Background Tasks { #dependencies-with-yield-httpexception-except-and-background-tasks }

/// warning

You most probably don't need these technical details.

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

If you want to secure your API, there are several better things you can do, for example:

* Make sure you have well defined Pydantic models for your request bodies and responses.

/// note | Technical Details

If you have dependencies with `yield`, the exit code will run *after* the middleware.

If there were any background tasks (covered in the [Background Tasks](background-tasks.md){.internal-link target=_blank} section, you will see it later), they will run *after* all the middleware.

///

## Create a middleware { #create-a-middleware }

directory (the one containing this README). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install.html). You should also add the Go binary directory $GOROOT/bin to your shell's path. For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile: export GOROOT=$HOME/go export PATH=$PATH:$GOROOT/bin See doc/install.html for more details....

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices

You just need to declare a **Pydantic model** with the fields you want to receive as **form fields**, and then declare the parameter as `Form`:

{* ../../docs_src/request_form_models/tutorial001_an_py39.py hl[9:11,15] *}

**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

### Check the responses { #check-the-responses }

Now, if you go to the URL with the port for Uvicorn: <a href="http://127.0.0.1:8000/app" class="external-link" target="_blank">http://127.0.0.1:8000/app</a>, you will see the normal response:

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

/// tip

Here I'll show you how to use **Uvicorn** with **worker processes** using the `fastapi` command or the `uvicorn` command directly.

/// info

If you are using containers, for example with Docker or Kubernetes, I'll tell you more about that in the next chapter: [FastAPI in Containers - Docker](docker.md){.internal-link target=_blank}.

If you already have a **FastAPI Cloud** account (we invited you from the waiting list 😉), you can deploy your application with one command.

Before deploying, make sure you are logged in:

<div class="termy">

```console
$ fastapi login

You are logged in to FastAPI Cloud 🚀
```

</div>

Then deploy your app: