Y entonces **FastAPI** llamará a esa dependencia para sobreescribir en lugar de la dependencia original.

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip | Consejo

Puedes sobreescribir una dependencia utilizada en cualquier lugar de tu aplicación **FastAPI**.

And then **FastAPI** will call that override instead of the original dependency.

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip

You can set a dependency override for a dependency used anywhere in your **FastAPI** application.

/// tip | Dica

No próximo capítulo, você verá uma implementação realmente segura, com hash de senha e tokens <abbr title="JSON Web Tokens">JWT</abbr>.

Mas, por enquanto, vamos nos concentrar nos detalhes específicos de que precisamos.

///

{* ../../docs_src/security/tutorial003_an_py310.py hl[87] *}

/// tip | Dica

#         integration-tests/gradle/gradlew
#         integration-tests/gradle/gradlew.bat
# Please commit your changes or stash them before you switch branches.

GRADLE_TEMP="$(mktemp -d)"
trap 'rm -rf "${GRADLE_TEMP}"' EXIT

# The Gradle tests need the pom.xml only to read its version number.
# (And the file needs to be two directory levels up from the Gradle build file.)

/// tip | Dica

O "PATCH" é o último número, por exemplo, em `0.2.3`, a versão PATCH é `3`.

///

Logo, você deveria conseguir fixar a versão, como:

```txt
fastapi>=0.45.0,<0.46.0
```

Mudanças significativas e novas funcionalidades são adicionadas em versões "MINOR".

/// tip | Dica

        Directory projectRootDir,
        File currentUpgradedPropertiesFile,
        File baselineUpgradedPropertiesFile,
        Action<RichReport> configureReport
    ) {
        japicmpTask.tap {
            addExcludeFilter(AnonymousClassesFilter)
            addExcludeFilter(KotlinInternalFilter)
            addExcludeFilter(KotlinInvokeDefaultBridgeFilter)

    }
}
```

/// tip | Consejo

Observa el server auto-generado con un valor `url` de `/api/v1`, tomado del `root_path`.

///

En la UI de los docs en <a href="http://127.0.0.1:9999/api/v1/docs" class="external-link" target="_blank">http://127.0.0.1:9999/api/v1/docs</a> se vería como:

<img src="/img/tutorial/behind-a-proxy/image03.png">

/// tip | Consejo

/// tip | Consejo

# Environment Variables { #environment-variables }

/// tip

If you already know what "environment variables" are and how to use them, feel free to skip this.

///

An environment variable (also known as "**env var**") is a variable that lives **outside** of the Python code, in the **operating system**, and could be read by your Python code (or by other programs as well).

But now, having `Query(max_length=50)` inside of `Annotated`, we are telling FastAPI that we want it to have **additional validation** for this value, we want it to have maximum 50 characters. 😎

/// tip

Here we are using `Query()` because this is a **query parameter**. Later we will see others like `Path()`, `Body()`, `Header()`, and `Cookie()`, that also accept the same arguments as `Query()`.

///