<img src="/img/deployment/https/https01.svg">

### TLS Handshake Start

The browser would then communicate with that IP address on **port 443** (the HTTPS port).

The first part of the communication is just to establish the connection between the client and the server and to decide the cryptographic keys they will use, etc.

<img src="/img/deployment/https/https02.svg">

This Manager Process would probably be the one listening on the **port** in the IP. And it would transmit all the communication to the worker processes.

Those worker processes would be the ones running your application, they would perform the main computations to receive a **request** and return a **response**, and they would load anything you put in variables in RAM.

## Top Translation Reviewers

These users are the **Top Translation Reviewers**. 🕵️

```

means:

* Starting in the same package that this module (the file `app/main.py`) lives in (the directory `app/`)...
* look for the subpackage `routers` (the directory at `app/routers/`)...
* and from it, import the submodule `items` (the file at `app/routers/items.py`) and `users` (the file at `app/routers/users.py`)...

client = TestClient(app)


def test_dependency_contextvars():
    """
    Check that custom middlewares don't affect the contextvar context for dependencies.

    The code before yield and the code after yield should be run in the same contextvar
    context, so that request_state_context_var.reset(contextvar_token).

    If they are run in a different context, that raises an error.
    """
    response = client.get("/user")

For some types of applications you might want to add dependencies to the whole application.

Similar to the way you can [add `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, you can add them to the `FastAPI` application.

In that case, they will be applied to all the *path operations* in the application:

=== "Python 3.9+"

    ```Python hl_lines="16"

    ```

...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

If you interact with the docs and check the response, even though the code didn't add anything in one of the `description` fields, the JSON response contains the default value (`null`):

<div class="screenshot">

```

Here we declare the setting `openapi_url` with the same default of `"/openapi.json"`.

And then we use it when creating the `FastAPI` app.

Then you could disable OpenAPI (including the UI docs) by setting the environment variable `OPENAPI_URL` to the empty string, like:

<div class="termy">

```console
$ OPENAPI_URL= uvicorn main:app

```

</div>

And copy the output to the variable `SECRET_KEY` (don't use the one in the example).

Create a variable `ALGORITHM` with the algorithm used to sign the JWT token and set it to `"HS256"`.

Create a variable for the expiration of the token.

Define a Pydantic Model that will be used in the token endpoint for the response.

Create a utility function to generate a new access token.

You will see the automatic API docs for the main app, including only its own _path operations_:

<img src="/img/tutorial/sub-applications/image01.png">

And then, open the docs for the sub-application, at <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>.