Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

But if you have a bunch of dataclasses laying around, this is a nice trick to use them to power a web API using FastAPI. 🤓

///

## Dataclasses in `response_model` { #dataclasses-in-response-model }

You can also use `dataclasses` in the `response_model` parameter:

The `root_path` is used to handle these specific cases.

And it's also used internally when mounting sub-applications.

Having a proxy with a stripped path prefix, in this case, means that you could declare a path at `/app` in your code, but then, you add a layer on top (the proxy) that would put your **FastAPI** application under a path like `/api/v1`.

    ```python
    from typing import Annotated

    from fastapi import Security, FastAPI

    from .db import User
    from .security import get_current_active_user

    app = FastAPI()

    @app.get("/users/me/items/")
    async def read_own_items(
        current_user: Annotated[User, Security(get_current_active_user, scopes=["items"])]
    ):

* `breaking`: Breaking Changes
    * Existing code will break if they update the version without changing their code. This rarely happens, so this label is not frequently used.
* `security`: Security Fixes
    * This is for security fixes, like vulnerabilities. It would almost never be used.
* `feature`: Features

Used by Pydantic:

* [`email-validator`](https://github.com/JoshData/python-email-validator) - for email validation.

Used by Starlette:

* [`httpx`](https://www.python-httpx.org) - Required if you want to use the `TestClient`.
* [`jinja2`](https://jinja.palletsprojects.com) - Required if you want to use the default template configuration.

#      Ex. macos_arm64      -- arm64 MacOS platform
# 3. Add modifiers. Some modifiers for local execution are:
#      Ex. disk_cache -- Use a local cache
#      Ex. public_cache -- Use TF's public cache (read-only)
#      Ex. public_cache_push -- Use TF's public cache (read and write, Googlers only)
#      Ex. rbe        -- Use RBE for faster builds (Googlers only; see below)
#      Ex. no_docker  -- Disable docker on enabled platforms

```plaintext
/home/user/code/awesome-project/.venv/bin/python
```

and use that one.

////

//// tab | Windows

```plaintext
C:\Users\user\code\awesome-project\.venv\Scripts;C:\Windows\System32
```

That means that the system will now start looking first for programs in:

```plaintext
C:\Users\user\code\awesome-project\.venv\Scripts
```

    private static final Logger logger = LogManager.getLogger(FessBaseAction.class);

    /** The application type for FESs, e.g. used by access context. */
    protected static final String APP_TYPE = "FES"; // #change_it_first

    /** The user type for Admin, e.g. used by access context. */
    protected static final String USER_TYPE = "A";

That way, you can create a token with an expiration of, let's say, 1 week. And then when the user comes back the next day with the token, you know that user is still logged in to your system.

   * For example, the cache may evict an entry because it hasn't been used recently or very often.
   *
   * <p>If {@code maximumSize} is zero, elements will be evicted immediately after being loaded into
   * cache. This can be useful in testing, or to disable caching temporarily.
   *
   * <p>This feature cannot be used in conjunction with {@link #maximumWeight}.
   *