Import `Form` from `fastapi`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[3] *}

## Define `Form` parameters { #define-form-parameters }

Create form parameters the same way you would for `Body` or `Query`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[9] *}

Or you might have any other way to communicate with the WebSocket endpoint.

---

But for this example, we'll use a very simple HTML document with some JavaScript, all inside a long string.

This, of course, is not optimal and you wouldn't use it for production.

In production you would have one of the options above.

But it's the simplest way to focus on the server-side of WebSockets and have a working example:

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.

# Learn { #learn }

Here are the introductory sections and the tutorials to learn **FastAPI**.

These are the exceptions that you can raise to show errors to the client.

When you raise an exception, as would happen with normal Python, the rest of the execution is aborted. This way you can raise these exceptions from anywhere in the code to abort a request and show the error to the client.

You can use:

* `HTTPException`
* `WebSocketException`

 limitations under the License.
-->
Contributing to Apache Maven
======================

You have found a bug or you have an idea for a cool new feature? Contributing
code is a great way to give something back to the open source community. Before
you dig right into the code, there are a few guidelines that we need
contributors to follow so that we can have a chance of keeping on top of
things.

ASoa,IAC5BL,GAAcjkB,IAAIskB,IACb1a,QAAQsa,GAAiBhW,KAAKkW,EAAUI,YAO5CH,EAAqBxX,QAAO4X,GAAkBA,aAA0BxW,SAC5EyW,MAAKC,GAASA,EAAMzW,KAAKoW,IAAe,EC5DvCpX,GAAU,CACd0X,UAAWxC,GACXyC,QAAS,GACTC,WAAY,GACZC,MAAM,EACNC,UAAU,EACVC,WAAY,KACZC,SAAU,eAGN/X,GAAc,CAClByX,UAAW,SACXC,QAAS,SACTC,WAAY,oBACZC,KAAM,UACNC,SAAU,UACVC,WAAY,kBACZC,SAAU,UAGNC,GAAqB,CACzBC,MAAO,iCACPvkB,SAAU,oBAOZ,MAAMwkB,WAAwBpY,EAC5BU,YAAYL,GACVgB,QACAxF,KAAK0F,QAAU1F,KAAKuE,WAAWC,EACjC,CAGWJ,qBACT,OAAOA,EACT,CAEWC,yBACT,OAAOA,EACT,CAEW/I,...

    /**
     * Retrieve all addresses of a host by it's address. NetBIOS hosts can
     * have many names for a given IP address. The name and IP address make the
     * NetBIOS address. This provides a way to retrieve the other names for a
     * host with the same IP address.
     *
     * @param addr
     *            the address to query
     * @return resolved addresses
     * @throws UnknownHostException

Import `File` and `UploadFile` from `fastapi`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[3] *}

## Define `File` Parameters { #define-file-parameters }

Create file parameters the same way you would for `Body` or `Form`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[9] *}

/// info

`File` is a class that inherits directly from `Form`.

        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note

Notice that even though the `item` was declared the same way as before, it is now expected to be inside of the body with a key `item`.

///

**FastAPI** will do the automatic conversion from the request, so that the parameter `item` receives its specific content and the same for `user`.