lang_to_discussion_map: Dict[str, AllDiscussionsDiscussionNode] = {}
    for discussion in discussions:
        for edge in discussion.labels.edges:
            label = edge.node.name
            if label.startswith("lang-") and not label == lang_all_label:
                lang = label[5:]
                lang_to_discussion_map[lang] = discussion
    logging.debug(f"Using translations map: {lang_to_discussion_map}")

{% for section_name, section_content in external_links.items() %}

## {{ section_name }}

{% for lang_name, lang_content in section_content.items() %}

### {{ lang_name }}

{% for item in lang_content %}

## Previous Steps Before Starting

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.

So, you will want to have a **single process** to perform those **previous steps**, before starting the application.

## 📄

{% for section_name, section_content in external_links.items() %}

## {{ section_name }}

{% for lang_name, lang_content in section_content.items() %}

### {{ lang_name }}

{% for item in lang_content %}

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

!!! danger
    This is an "advanced" feature.

    If you are just starting with **FastAPI** you might want to skip this section.

## Use cases

# Reference - Code API

Here's the reference or code API, the classes, functions, parameters, attributes, and
all the FastAPI parts you can use in your applications.

If you want to **learn FastAPI** you are much better off reading the

```Python hl_lines="3" title="app/internal/admin.py"
{!../../../docs_src/bigger_applications/app/internal/admin.py!}
```

But we still want to set a custom `prefix` when including the `APIRouter` so that all its *path operations* start with `/admin`, we want to secure it with the `dependencies` we already have for this project, and we want to include `tags` and `responses`.

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

::: fastapi.WebSocket
    options:

# Global Dependencies

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"

* MySQL
* SQLite

In this example, we'll use **SQLite**, because it uses a single file and Python has integrated support. So, you can copy this example and run it as is.

Later, for your production application, you might want to use a database server like **PostgreSQL**.

!!! tip