# 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.

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:

...

 * 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>
 *

Digamos que você tenha uma *operação de rota* com um path `/files/{file_path}`.

Mas você precisa que o próprio `file_path` contenha um *path*, como `home/johndoe/myfile.txt`.

Então, a URL para esse arquivo seria algo como: `/files/home/johndoe/myfile.txt`.

### Suporte do OpenAPI { #openapi-support }

{* ../../docs_src/path_params/tutorial004_py310.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:

 * 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>
 *

   *
   * Fundamentally, there's not really anything we can do about that. In the unlikely event that it
   * comes up in practice (maybe through some kind of sanitizer-like testing that intentionally
   * inflicts spurious interrupts on us?), we might have to accept some flakiness or disable some
   * tests, at least under whichever environment (JRE or Android) we see such problems.
   */

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

In OkHttp some fields of the address come from the URL (scheme, hostname, port) and the rest come from the [OkHttpClient](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-ok-http-client/).

### [Routes](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-route/)