{* ../../docs_src/server_sent_events/tutorial005_py310.py hl[14] *}

## Technical Details { #technical-details }

FastAPI implements some SSE best practices out of the box.

## Code includes with unknown attributes { #code-includes-with-unknown-attributes }

{* ../../docs_src/python_types/tutorial001_py310.py unknown[123] *}

## Some more code includes to test fixing { #some-more-code-includes-to-test-fixing }

{* ../../docs_src/dependencies/tutorial013_an_py310.py ln[19:21] *}

     */
    @Test
    public void testErrorMessage_ja() throws Exception {
        // ## Arrange ##
        Locale.setDefault(Locale.JAPANESE);
        final SQLException sqlException = new SQLException("some reason", "fooState", 7650);
        final SQLException sqlException2 = new SQLException("hoge reason", "barState", 7660);
        final SQLException sqlException3 = new SQLException("fuga reason", "bazState", 7670);

```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.

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

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.

///

///

And we are using this model to declare our input and the same model to declare our output:

{* ../../docs_src/response_model/tutorial002_py310.py hl[16] *}

Now, whenever a browser is creating a user with a password, the API will return the same password in the response.

In this case, it might not be a problem, because it's the same user sending the password.

    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      // Even though the contract in System.getProperties() specifies that a value will exist for
      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {
        continue;
      }
      // Removed in Java 9:

## Forbid Extra Query Parameters { #forbid-extra-query-parameters }

In some special use cases (probably not very common), you might want to **restrict** the query parameters that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

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