## About proxies with a stripped path prefix

Keep in mind that a proxy with stripped path prefix is only one of the ways to configure it.

Probably in many cases the default will be that the proxy doesn't have a stripped path prefix.

And the more exotic ones:

* `@app.options()`
* `@app.head()`
* `@app.patch()`
* `@app.trace()`

!!! tip
    You are free to use each operation (HTTP method) as you wish.

    **FastAPI** doesn't enforce any specific meaning.

    The information here is presented as a guideline, not a requirement.

    For example, when using GraphQL you normally perform all the actions using only `POST` operations.

* A particular program while it is **running** on the operating system.
    * This doesn't refer to the file, nor to the code, it refers **specifically** to the thing that is being **executed** and managed by the operating system.

That documentation will show up in the Swagger UI at `/docs` in your API, and it will let external developers know how to build the *external API*.

This example doesn't implement the callback itself (that could be just a line of code), only the documentation part.

!!! tip
    The actual callback is just an HTTP request.

        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="68-69  81"
    {!> ../../../docs_src/websockets/tutorial002.py!}
    ```

!!! info
    As this is a WebSocket it doesn't really make sense to raise an `HTTPException`, instead we raise a `WebSocketException`.

If you used to rely on this behavior, now you should create the resources for background tasks inside the background task itself, and use internally only data that doesn't depend on the resources of dependencies with `yield`.

!!! tip
    A file starting with a dot (`.`) is a hidden file in Unix-like systems, like Linux and macOS.

    But a dotenv file doesn't really have to have that exact filename.

3. Copy the file with the requirements to the `/code` directory.

    Copy **only** the file with the requirements first, not the rest of the code.

    As this file **doesn't change often**, Docker will detect it and use the **cache** for this step, enabling the cache for the next step too.

4. Install the package dependencies in the requirements file.