/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

Make sure you evaluate if the **benefits** for your use case compensate the **drawbacks**. 🤓

///

## GraphQL Libraries { #graphql-libraries }

* Great editor support.
* Data conversion from incoming requests.
* Data conversion for response data.
* Data validation.
* Automatic annotation and documentation.

## Other data types { #other-data-types }

Here are some of the additional data types you can use:

* `UUID`:
    * A standard "Universally Unique Identifier", common as an ID in many databases and systems.
    * In requests and responses will be represented as a `str`.

looking at Alice for some time with great curiosity, and this was
his first speech.

  `You should learn not to make personal remarks,' Alice said
with some severity; `it's very rude.'

  The Hatter opened his eyes very wide on hearing this; but all
he SAID was, `Why is a raven like a writing-desk?'

  `Come, we shall have some fun now!' thought Alice.  `I'm glad

```json
{
    "description": "Some data",
    "data": "aGVsbG8="
}
```

/// tip

`aGVsbG8=` is the base64 encoding of `hello`.

///

And then Pydantic will decode the base64 string and give you the original bytes in the `data` field of the model.

You will receive a response like:

```json
{
  "description": "Some data",
  "content": "hello"
}
```

# Configure Swagger UI { #configure-swagger-ui }

You can configure some extra [Swagger UI parameters](https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/).

To configure them, pass the `swagger_ui_parameters` argument when creating the `FastAPI()` app object or to the `get_swagger_ui_html()` function.

`swagger_ui_parameters` receives a dictionary with the configurations passed to Swagger UI directly.

If for some reason you need to disable automatic conversion of underscores to hyphens, set the parameter `convert_underscores` of `Header` to `False`:

{* ../../docs_src/header_params/tutorial002_an_py310.py hl[10] *}

/// warning

Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

///

# Advanced Python Types { #advanced-python-types }

Here are some additional ideas that might be useful when working with Python types.

## Using `Union` or `Optional` { #using-union-or-optional }

If your code for some reason can't use `|`, for example if it's not in a type annotation but in something like `response_model=`, instead of using the vertical bar (`|`) you can use `Union` from `typing`.

                        url = "\$buildDir/repo"
                    }
                 }
            }
            version = "1.0"
            group = 'org.acme' 
            description = 'some description'       
        """

        when:
        def result = gradleRunner('assemble', '--stacktrace').build()

        then:
        result.task(":generatePom").outcome == TaskOutcome.SUCCESS

    * This is particularly important for **security**, we'll see more of that below.

## `response_model` Parameter { #response-model-parameter }

There are some cases where you need or want to return some data that is not exactly what the type declares.

* Be careful when using features introduced in Java 9 or later. Some parts of Gradle still need to run on Java 8.
* Normalize file paths in tests. The `org.gradle.util.internal.TextUtil` class has some useful functions for this purpose.

You can consult the [Architecture documentation](architecture) to learn about some of the architecture of Gradle.