I'll show you some concrete examples in the next chapters.

---

Then the next concepts to consider are all about the program running your actual API (e.g. Uvicorn).

## Program and Process

We will talk a lot about the running "**process**", so it's useful to have clarity about what it means, and what's the difference with the word "**program**".

### What is a Program

    * That's one layer **below HTTP**.
    * So, the **certificate and encryption** handling is done **before HTTP**.
* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.

I think `Union[SomeType, None]` is more explicit about what it means.

It's just about the words and names. But those words can affect how you and your teammates think about the code.

As an example, let's take this function:

```Python hl_lines="1  4"
{!../../../docs_src/python_types/tutorial009c.py!}
```

    ```

And all the ideas in the section about [adding `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank} still apply, but in this case, to all of the *path operations* in the app.

## Dependencies for groups of *path operations*

# ~~Async SQL (Relational) Databases with Encode/Databases~~ (deprecated)

!!! info
    These docs are about to be updated. 🎉

    The current version assumes Pydantic v1.

    The new docs will include Pydantic v2 and will use <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel</a> once it is updated to use Pydantic v2 as well.

!!! warning "Deprecated"

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

## Details about the `Request` object

And the sub-application could also have its own mounted sub-applications and everything would work correctly, because FastAPI handles all these `root_path`s automatically.

# Templating - `Jinja2Templates`

You can use the `Jinja2Templates` class to render Jinja templates.

Read more about it in the [FastAPI docs for Templates](https://fastapi.tiangolo.com/advanced/templates/).

You can import it directly from `fastapi.templating`:

```python
from fastapi.templating import Jinja2Templates
```

blank_issues_enabled: false
contact_links:
  - name: Security Contact
    about: Please report security vulnerabilities to ******@****.***
  - name: Question or Problem
    about: Ask a question or ask about a problem in GitHub Discussions.
    url: https://github.com/tiangolo/fastapi/discussions/categories/questions
  - name: Feature Request

    And those two things, `scope` and `receive`, are what is needed to create a new `Request` instance.

    To learn more about the `Request` check <a href="https://www.starlette.io/requests/" class="external-link" target="_blank">Starlette's docs about Requests</a>.

The only thing the function returned by `GzipRequest.get_route_handler` does differently is convert the `Request` to a `GzipRequest`.