## Úsalo

Ahora puedes declarar tu dependencia usando esta clase.

{* ../../docs_src/dependencies/tutorial002_an_py310.py hl[19] *}

**FastAPI** llama a la clase `CommonQueryParams`. Esto crea una "instance" de esa clase y la instance será pasada como el parámetro `commons` a tu función.

## Anotación de tipos vs `Depends`

Nota cómo escribimos `CommonQueryParams` dos veces en el código anterior:

{* ../../docs_src/websockets/tutorial001.py hl[2,6:38,41:43] *}

## Crear un `websocket`

En tu aplicación de **FastAPI**, crea un `websocket`:

{* ../../docs_src/websockets/tutorial001.py hl[1,46:47] *}

/// note | Detalles Técnicos

También podrías usar `from starlette.websockets import WebSocket`.

    * `url` (**requerido**): un `str` con la URL para la documentación externa.

### Crear metadata para etiquetas

Probemos eso en un ejemplo con etiquetas para `users` y `items`.

Crea metadata para tus etiquetas y pásala al parámetro `openapi_tags`:

{* ../../docs_src/metadata/tutorial004.py hl[3:16,18] *}

        // This is expected behavior - the reserved fields are not explicitly written to 0

        // Reserved2 (4 bytes) - should be 0 (bytes were initialized to 0xCC, so they weren't written)
        // This is expected behavior - the reserved fields are not explicitly written to 0

        // FileId (16 bytes) - should match our test file ID

## Pydantic

Tüm veri doğrulamaları <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> tarafından arka planda gerçekleştirilir, bu sayede tüm avantajlardan faydalanabilirsiniz. Böylece, emin ellerde olduğunuzu hissedebilirsiniz.

Aynı tip tanımlamalarını `str`, `float`, `bool` ve diğer karmaşık veri tipleri ile kullanma imkanınız vardır.

///

### Crear un `APIRouter` de callback

Primero crea un nuevo `APIRouter` que contendrá uno o más callbacks.

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[3,25] *}

### Crear la *path operation* del callback

* **WebSocket** desteği.
* **GraphQL** desteği.
* Kullanım halinde arka plan işlevleri.
* Başlatma ve kapatma eventleri(startup and shutdown).
* Test sunucusu HTTPX üzerine kurulu.
* **CORS**, GZip, Static dosyalar, Streaming responseları.
* **Session and Cookie** desteği.

text-indent: -999px;\n    cursor: pointer;\n    background-color: $carousel-indicator-active-bg;\n    background-clip: padding-box;\n    // Use transparent borders to increase the hit area by 10px on top and bottom.\n    border-top: $carousel-indicator-hit-area-height solid transparent;\n    border-bottom: $carousel-indicator-hit-area-height solid transparent;\n    opacity: .5;\n    @include transition($carousel-indicator-transition);\n  }\n\n  .active {\n    opacity: 1;\n  }\n}\n\n\n// Optional captions\...

packaging.fess.heap.min=256m
packaging.fess.heap.max=1g

# Specifies the maximum file descriptor number
packaging.os.max.open.files=65535

# Maximum number of VMA (Virtual Memory Areas) a process can own
packaging.os.max.map.count=262144

# Simple marker to check that properties are correctly overridden
packaging.type=tar.gz

# Custom header for package scripts
packaging.scripts.header=

That's what we'll solve, let's load the model before the requests are handled, but only right before the application starts receiving requests, not while  the code is being loaded.

## Lifespan { #lifespan }