!!! warning
    The supporting additional functions are just to demo a possible flow of the data, but they of course are not providing any real security.

## Reduce duplication

Reducing code duplication is one of the core ideas in **FastAPI**.

As code duplication increments the chances of bugs, security issues, code desynchronization issues (when you update in one place but not in the others), etc.

need to have a model with all the attributes marked as optional (with default values or `None`).

    To distinguish from the models with all optional values for **updates** and models with required values for **creation**, you can use the ideas described in [Extra Models](extra-models.md){.internal-link target=_blank}....

## Recap

You can use **Gunicorn** (or also Uvicorn) as a process manager with Uvicorn workers to take advantage of **multi-core CPUs**, to run **multiple processes in parallel**.

You could use these tools and ideas if you are setting up **your own deployment system** while taking care of the other deployment concepts yourself.

* Read what I write (or follow me) on <a href="https://dev.to/tiangolo" class="external-link" target="_blank">**Dev.to**</a> or <a href="https://medium.com/@tiangolo" class="external-link" target="_blank">**Medium**</a>.
    * Read other ideas, articles, and read about tools I have created.
    * Follow me to read when I publish something new.

## Tweet about **FastAPI**

    You can consider this a brief OpenAPI and JSON Schema **history lesson**. 🤓

!!! warning
    These are very technical details about the standards **JSON Schema** and **OpenAPI**.

    If the ideas above already work for you, that might be enough, and you probably don't need these details, feel free to skip them.

Before OpenAPI 3.1.0, OpenAPI used an older and modified version of **JSON Schema**.

The most common way to do it is to have a file `requirements.txt` with the package names and their versions, one per line.

You would of course use the same ideas you read in [About FastAPI versions](versions.md){.internal-link target=_blank} to set the ranges of versions.

For example, your `requirements.txt` could look like:

```
fastapi>=0.112.0,<0.113.0

Usuário** (que você está lendo agora).

Ele foi projetado para que você possa construir uma aplicação completa com apenas o **Tutorial - Guia de Usuário**, e então estendê-la de diferentes formas, dependendo das suas necessidades, usando algumas ideias adicionais do **Guia Avançado de Usuário**....

möglicherweise den TLS-Terminierungsproxy vorübergehend stoppen, das Programm starten, welches die neuen Zertifikate beschafft, diese dann mit dem TLS-Terminierungsproxy konfigurieren und dann den TLS-Terminierungsproxy neu starten. Das ist nicht ideal, da Ihre Anwendung(en) während der Zeit, in der der TLS-Terminierungsproxy ausgeschaltet ist, nicht erreichbar ist/sind.

Dieser ganze Erneuerungsprozess, während die Anwendung weiterhin bereitgestellt wird, ist einer der Hauptgründe, warum...

## Deployment Concepts

These examples run the server program (e.g Uvicorn), starting **a single process**, listening on all the IPs (`0.0.0.0`) on a predefined port (e.g. `80`).

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

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

but this time at the URL with the prefix path provided by the proxy: `/api/v1`.

Of course, the idea here is that everyone would access the app through the proxy, so the version with the path prefix `/api/v1` is the "correct" one.