### `HTMLResponse` { #htmlresponse }

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse` { #plaintextresponse }

Takes some text or bytes and returns a plain text response.

{* ../../docs_src/custom_response/tutorial005_py39.py hl[2,7,9] *}

### `JSONResponse` { #jsonresponse }

Takes some data and returns an `application/json` encoded response.

    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17
    on Linux, with some additional testing on newer JDKs and on Windows. Some
    features, especially in `com.google.common.io`, may not work correctly in
    non-Linux environments. For the Android flavor, our unit tests also run on
    API level 23 (Marshmallow).

            JOB_BRANCH=%BRANCH%
            HOME=$JENKINS_HOME
            GRADLEW=./gradlew --parallel --scan --build-cache -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
            GRADLEW_BAT=./gradlew.bat --parallel --scan --build-cache -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
    publishers:
# Disable Junit publisher for now since it's causing OOME on our Jenkins instance
#      - junit:

    public void execute(MavenSession session) {
        lifecycleStarter.execute(session);
    }

    // These methods deal with construction intact Plugin object that look like they come from a standard
    // <plugin/> block in a Maven POM. We have to do some wiggling to pull the sources of information
    // together and this really shows the problem of constructing a sensible default configuration, but

thoroughly before moving to code.

Some examples of types of pull requests that are immediately helpful:

  - Fixing a bug without changing a public API.
  - Fixing or improving documentation.
  - Improvements to Maven configuration.

Guidelines for any code contributions:

1.  Any significant changes should be accompanied by tests. The project already
    has good test coverage, so look at some existing tests if you're unsure how

 * second invocation, so implementors have made various choices, including:
 *
 * <ul>
 *   <li>returning the same iterator again
 *   <li>throwing an exception of some kind
 *   <li>or the usual, <i>robust</i> behavior, which all known {@link Collection} implementations
 *       have, of returning a new, independent iterator
 * </ul>
 *

They are handled automatically by **FastAPI** and converted to JSON.

///

## Add custom headers { #add-custom-headers }

There are some situations in where it's useful to be able to add custom headers to the HTTP error. For example, for some types of security.

You probably won't need to use it directly in your code.

But in case you needed it for an advanced scenario, you can add custom headers:

This is the basic idea. But you will probably want to take care of some additional things, like:

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory
* Previous steps before starting

{* ../../docs_src/path_params/tutorial004_py39.py hl[6] *}

/// tip

You might need the parameter to contain `/home/johndoe/myfile.txt`, with a leading slash (`/`).

In that case, the URL would be: `/files//home/johndoe/myfile.txt`, with a double slash (`//`) between `files` and `home`.

///

## Recap { #recap }

With **FastAPI**, by using short, intuitive and standard Python type declarations, you get:

# Custom Docs UI Static Assets (Self-Hosting) { #custom-docs-ui-static-assets-self-hosting }

The API docs use **Swagger UI** and **ReDoc**, and each of those need some JavaScript and CSS files.