### Always `raise` in Dependencies with `yield` and `except` { #always-raise-in-dependencies-with-yield-and-except }

If you catch an exception in a dependency with `yield`, unless you are raising another `HTTPException` or similar, you should re-raise the original exception.

You can re-raise the same exception using `raise`:

{* ../../docs_src/dependencies/tutorial008d_an_py39.py hl[17] *}

### Raise an `HTTPException` in your code { #raise-an-httpexception-in-your-code }

`HTTPException` is a normal Python exception with additional data relevant for APIs.

Because it's a Python exception, you don't `return` it, you `raise` it.

They can declare request requirements (like headers) or other sub-dependencies:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Raise exceptions { #raise-exceptions }

These dependencies can `raise` exceptions, the same as normal dependencies:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Return values { #return-values }

{* ../../docs_src/websockets/tutorial002_an_py310.py hl[68:69,82] *}

/// info

As this is a WebSocket it doesn't really make sense to raise an `HTTPException`, instead we raise a `WebSocketException`.

You can use a closing code from the <a href="https://tools.ietf.org/html/rfc6455#section-7.4.1" class="external-link" target="_blank">valid codes defined in the specification</a>.

{* ../../docs_src/security/tutorial005_an_py310.py hl[47,117:129] *}

## Verify the `scopes` { #verify-the-scopes }

We now verify that all the scopes required, by this dependency and all the dependants (including *path operations*), are included in the scopes provided in the token received, otherwise raise an `HTTPException`.

`security_scopes` 🎚 (🎓 `SecurityScopes`) 🚚 `scope_str` 🔢 ⏮️ 👁 🎻, 🔌 👈 ↔ 👽 🚀 (👥 🔜 ⚙️ ⚫️).

👥 ✍ `HTTPException` 👈 👥 💪 🏤-⚙️ (`raise`) ⏪ 📚 ☝.

👉 ⚠, 👥 🔌 ↔ 🚚 (🚥 🙆) 🎻 👽 🚀 (⚙️ `scope_str`). 👥 🚮 👈 🎻 ⚗ ↔ `WWW-Authenticate` 🎚 (👉 🍕 🔌).

{* ../../docs_src/security/tutorial005.py hl[105,107:115] *}

## ✔ `username` & 💽 💠

Wir erstellen eine `HTTPException`, die wir später an mehreren Stellen wiederverwenden (`raise`n) können.

Nós criamos uma `HTTPException` que nós podemos reutilizar (`raise`) mais tarde em diversos lugares.

Creamos una `HTTPException` que podemos reutilizar (`raise`) más tarde en varios puntos.

    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
        handler -->> client: HTTP error response
        dep -->> dep: Raise other exception
    end