"content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Items",
                    "operationId": "some_specific_id_you_define",
                }
            }
        },

So, if the `dict` contains:

```Python
{
    "username": "johndoe",
    "hashed_password": "some_hash",
}
```

It will be passed to `UserInDB` as:

```Python
UserInDB(username="johndoe", hashed_password="some_hash")
```

## Create your **FastAPI** code

### Create the `FastAPI` app

```Python hl_lines="46"

### About `{**note.dict(), "id": last_record_id}`

`note` is a Pydantic `Note` object.

`note.dict()` returns a `dict` with its data, something like:

```Python
{
    "text": "Some note",
    "completed": False,
}
```

but it doesn't have the `id` field.

So we create a new `dict`, that contains the key-value pairs from `note.dict()` with:

```Python
{**note.dict()}
```

@app.get("/items/{item_id}")
async def read_item(item_id: str):
    if item_id not in items:
        raise HTTPException(
            status_code=404,
            detail="Item not found",
            headers={"X-Error": "Some custom header"},
        )
    return {"item": items[item_id]}


@app.get("/http-no-body-statuscode-exception")
async def no_body_status_code_exception():
    raise HTTPException(status_code=204)

* ...etc.

Nevertheless, you might have a very specific use case where you really need to disable the API docs for some environment (e.g. for production) or depending on configurations from environment variables.

## Conditional OpenAPI from settings and env vars

You can easily use the same Pydantic settings to configure your generated OpenAPI and the docs UIs.

For example:

```Python hl_lines="6  11"

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

# 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"

<font color="#3465A4">INFO    </font> Resolved absolute path <font color="#75507B">/home/user/code/awesomeapp/</font><font color="#AD7FA8">main.py</font>
<font color="#3465A4">INFO    </font> Searching for package file structure from directories with <font color="#3465A4">__init__.py</font> files
<font color="#3465A4">INFO    </font> Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

👈 ⚫️❔, 💬 🛂 🕸:

> 📨 1️⃣ 🏆 ⏬ 🐍 📦 🌐 🕰

🌌 👆 ⚙️ ⚫️ 📶 🙅. 🖼, `GET` 📨, 👆 🔜 ✍:

```Python
response = requests.get("http://example.com/some/url")
```

FastAPI 😑 🛠️ *➡ 🛠️* 💪 👀 💖:

```Python hl_lines="1"
@app.get("/some/url")
def read_url():
    return {"message": "Hello World"}
```

👀 🔀 `requests.get(...)` & `@app.get(...)`.

!!! check "😮 **FastAPI** "

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps