# 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

    - how-to/nosql-databases-couchbase.md
- Reference (Code API):
  - reference/index.md
  - reference/fastapi.md
  - reference/parameters.md
  - reference/status.md
  - reference/uploadfile.md
  - reference/exceptions.md
  - reference/dependencies.md
  - reference/apirouter.md
  - reference/background.md
  - reference/request.md
  - reference/websockets.md
  - reference/httpconnection.md
  - reference/response.md

    schemas: Optional[Dict[str, Union[Schema, Reference]]] = None
    responses: Optional[Dict[str, Union[Response, Reference]]] = None
    parameters: Optional[Dict[str, Union[Parameter, Reference]]] = None
    examples: Optional[Dict[str, Union[Example, Reference]]] = None
    requestBodies: Optional[Dict[str, Union[RequestBody, Reference]]] = None
    headers: Optional[Dict[str, Union[Header, Reference]]] = None

# `APIRouter` class

Here's the reference information for the `APIRouter` class, with all its parameters, attributes and methods.

You can import the `APIRouter` class directly from `fastapi`:

```python
from fastapi import APIRouter
```

::: fastapi.APIRouter
    options:
        members:
            - websocket
            - include_router
            - get
            - put
            - post
            - delete

# `FastAPI` class

Here's the reference information for the `FastAPI` class, with all its parameters, attributes and methods.

You can import the `FastAPI` class directly from `fastapi`:

```python
from fastapi import FastAPI
```

::: fastapi.FastAPI
    options:
        members:
            - openapi_version
            - webhooks
            - state
            - dependency_overrides
            - openapi

Sie sollten eine sehr lange JavaScript-Datei für **ReDoc** sehen.

Sie könnte beginnen mit etwas wie:

```JavaScript
/*!
 * ReDoc - OpenAPI/Swagger-generated API Reference Documentation
 * -------------------------------------------------------------
 *   Version: "2.0.0-rc.18"
 *   Repo: https://github.com/Redocly/redoc
 */
!function(e,t){"object"==typeof exports&&"object"==typeof m

就能看到 **ReDoc** 的 JavaScript 文件。

该文件开头如下：

```JavaScript
/*!
 * ReDoc - OpenAPI/Swagger-generated API Reference Documentation
 * -------------------------------------------------------------
 *   Version: "2.0.0-rc.18"
 *   Repo: https://github.com/Redocly/redoc
 */
!function(e,t){"object"==typeof exports&&"object"==typeof m

# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

* 🌐 Add German translation for `docs/de/docs/reference/parameters.md`. PR [#10814](https://github.com/tiangolo/fastapi/pull/10814) by [@nilslindemann](https://github.com/nilslindemann).
* 🌐 Add German translation for `docs/de/docs/reference/status.md`. PR [#10815](https://github.com/tiangolo/fastapi/pull/10815) by [@nilslindemann](https://github.com/nilslindemann).

### ⚙️ 🔑 👨‍💼 🔗 ⏮️ `yield`

!!! warning
    👉, 🌅 ⚖️ 🌘, "🏧" 💭.

    🚥 👆 ▶️ ⏮️ **FastAPI** 👆 💪 💚 🚶 ⚫️ 🔜.

🐍, 👆 💪 ✍ 🔑 👨‍💼 <a href="https://docs.python.org/3/reference/datamodel.html#context-managers" class="external-link" target="_blank">🏗 🎓 ⏮️ 2️⃣ 👩‍🔬: `__enter__()` &amp; `__exit__()`</a>.

👆 💪 ⚙️ 👫 🔘 **FastAPI** 🔗 ⏮️ `yield` ⚙️
`with` ⚖️ `async with` 📄 🔘 🔗 🔢: