///

## Dependencies with `yield`, `HTTPException`, `except` and Background Tasks { #dependencies-with-yield-httpexception-except-and-background-tasks }

/// warning

You most probably don't need these technical details.

These details are useful mainly if you had a FastAPI application older than 0.121.0 and you are facing issues with dependencies with `yield`.

///

import okio.BufferedSink
import okio.GzipSink
import okio.buffer

internal class GzipRequestBody(
  val delegate: RequestBody,
) : RequestBody() {
  override fun contentType() = delegate.contentType()

  // We don't know the compressed length in advance!
  override fun contentLength() = -1L

  override fun writeTo(sink: BufferedSink) {
    GzipSink(sink).buffer().use(delegate::writeTo)
  }

But if you use the same model as an output, like here:

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py hl[19] *}

...then because `description` has a default value, if you **don't return anything** for that field, it will still have that **default value**.

### Model for Output Response Data { #model-for-output-response-data }

# OpenAPI

There are several utilities to handle OpenAPI.

///

## Response Status Code { #response-status-code }

You can define the (HTTP) `status_code` to be used in the response of your *path operation*.

You can pass directly the `int` code, like `404`.

But if you don't remember what each number code is for, you can use the shortcut constants in `status`:

{* ../../docs_src/path_operation_configuration/tutorial001_py310.py hl[1,15] *}

You only give `Depends` a single parameter.

This parameter must be something like a function.

You **don't call it** directly (don't add the parenthesis at the end), you just pass it as a parameter to `Depends()`.

And that function takes parameters in the same way that *path operation functions* do.

/// tip

        // Verify context is created and basic methods work
        assertNotNull(context, "Context should be created");
        assertNotNull(context.options(), "Options should be available");

        // Test that icon methods don't throw exceptions
        // (The actual icon choice depends on terminal charset capabilities)
        context.success("Test success message");
        context.failure("Test failure message");

        description =
            "Promotes a previously built distribution on this agent on '${branch.branchName}' from Quick Feedback as a new nightly snapshot. This build checks out gradle-promote, so don't be misled by the 'master' branch."

        steps {
            buildStep(
                ******@****.***arameters,

        ),
    ] = None,
    include_in_schema: Annotated[
        bool,
        Doc(
            """
            To include (or not) this parameter field in the generated OpenAPI.
            You probably don't need it, but it's available.

            This affects the generated OpenAPI (e.g. visible at `/docs`).
            """
        ),
    ] = True,
    json_schema_extra: Annotated[

            "ETag",
            "v1",
            "Vary",
            "Accept-Charset",
            "Donut",
            "a",
          ),
        body = "A",
      ),
    )
    server.enqueue(
      MockResponse
        .Builder()
        .clearHeaders()
        .addHeader("Donut: b")
        .code(HttpURLConnection.HTTP_NOT_MODIFIED)
        .build(),
    )
    client =