and MAY be relative, to indicate that the host location is relative
                to the location where the OpenAPI document is being served. Variable
                substitutions will be made when a variable is named in `{`brackets`}`.
                * `description`: An optional string describing the host designated by
                the URL. [CommonMark syntax](https://commonmark.org/) MAY be used for

    img: https://fastapi.tiangolo.com/img/sponsors/codacy.png
bronze:
  - url: https://www.exoflare.com/open-source/?utm_source=FastAPI&utm_campaign=open_source
    title: Biosecurity risk assessments made easy.
    img: https://fastapi.tiangolo.com/img/sponsors/exoflare.png
  - url: https://testdriven.io/courses/tdd-fastapi/
    title: Learn to build high-quality web apps with best practices

If you use a `try` block in a dependency with `yield`, you'll receive any exception that was thrown when using the dependency.

For example, if some code at some point in the middle, in another dependency or in a *path operation*, made a database transaction "rollback" or create any other error, you will receive the exception in your dependency.

So, you can look for that specific exception inside the dependency with `except SomeException`.

# İlk Adımlar

En sade FastAPI dosyası şu şekilde görünür:

```Python
{!../../../docs_src/first_steps/tutorial001.py!}
```

Yukarıdaki içeriği bir `main.py` dosyasına kopyalayalım.

Uygulamayı çalıştıralım:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

Docker has been one of the main tools to create and manage **container images** and **containers**.

And there's a public <a href="https://hub.docker.com/" class="external-link" target="_blank">Docker Hub</a> with pre-made **official container images** for many tools, environments, databases, and applications.

For example, there's an official <a href="https://hub.docker.com/_/python" class="external-link" target="_blank">Python Image</a>.