ion"==typeof define&&define.amd?define(["jquery"],function(a){return b(a)}):"object"==typeof module&&module.exports?module.exports=b(require("jquery")):b(a.jQuery)}(this,function(a){!function(a,b){"use strict";a.formUtils.registerLoadedModule("lang/it"),a(b).bind("validatorsLoaded",function(){a.formUtils.LANG={errorTitle:"Impossibile inviare il modulo!",requiredField:"Campo obbligatorio",requiredFields:"Non sono stati compilati tutti i campi richiesti",badTime:"L'ora scelta non è valida",badEmail:"Questo...

Let's use the tools provided by **FastAPI** to handle security.

## How it looks { #how-it-looks }

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

## Create `main.py` { #create-main-py }

Copy the example in a file `main.py`:

{* ../../docs_src/security/tutorial001_an_py310.py *}

## Run it { #run-it }

/// info

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare it as a parameter { #declare-it-as-a-parameter }

To add it to your *path operation*, declare it the same way you declared path and query parameters:

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

...and declare its type as the model you created, `Item`.

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

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:

* An optional query parameter `q` that is a `str`.

# WebSockets

When defining WebSockets, you normally declare a parameter of type `WebSocket` and with it you can read data from the client and send data to it.

Read more about it in the [FastAPI docs for WebSockets](https://fastapi.tiangolo.com/advanced/websockets/)

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

/// tip

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Let's focus on the parameters declared:

* Even though this function is a dependency ("dependable") itself, it also declares another dependency (it "depends" on something else).
    * It depends on the `query_extractor`, and assigns the value returned by it to the parameter `q`.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

{* ../../docs_src/events/tutorial003_py310.py hl[22] *}

## Alternative Events (deprecated) { #alternative-events-deprecated }

/// warning

If you declare it as is, because it is a singular value, **FastAPI** will assume that it is a query parameter.

But you can instruct **FastAPI** to treat it as another body key using `Body`:

{* ../../docs_src/body_multiple_params/tutorial003_an_py310.py hl[23] *}

You can use `jsonable_encoder` for that.

It receives an object, like a Pydantic model, and returns a JSON compatible version:

{* ../../docs_src/encoder/tutorial001_py310.py hl[4,21] *}

In this example, it would convert the Pydantic model to a `dict`, and the `datetime` to a `str`.

If you need to enforce it, use `OAuth2PasswordRequestFormStrict` instead of `OAuth2PasswordRequestForm`.

///

* An optional `client_id` (we don't need it for our example).
* An optional `client_secret` (we don't need it for our example).

/// info