# Encoders - `jsonable_encoder`

# Über

* 🚥 🔢 📣 **➡**, ⚫️ 🔜 ⚙️ ➡ 🔢.
* 🚥 🔢 **⭐ 🆎** (💖 `int`, `float`, `str`, `bool`, ♒️) ⚫️ 🔜 🔬 **🔢** 🔢.
* 🚥 🔢 📣 🆎 **Pydantic 🏷**, ⚫️ 🔜 🔬 📨 **💪**.

/// note

FastAPI 🔜 💭 👈 💲 `q` 🚫 ✔ ↩️ 🔢 💲 `= None`.

 `Union` `Union[str, None]` 🚫 ⚙️ FastAPI, ✋️ 🔜 ✔ 👆 👨‍🎨 🤝 👆 👍 🐕‍🦺 & 🔍 ❌.

///

## 🍵 Pydantic

# Sobre

{!../../docs_src/dependencies/tutorial011.py!}
```

👉 💼, 👉 `__call__` ⚫️❔ **FastAPI** 🔜 ⚙️ ✅ 🌖 🔢 & 🎧-🔗, & 👉 ⚫️❔ 🔜 🤙 🚶‍♀️ 💲 🔢 👆 *➡ 🛠️ 🔢* ⏪.

## 🔗 👐

& 🔜, 👥 💪 ⚙️ `__init__` 📣 🔢 👐 👈 👥 💪 ⚙️ "🔗" 🔗:

```Python hl_lines="7"
{!../../docs_src/dependencies/tutorial011.py!}
```

👉 💼, **FastAPI** 🏆 🚫 ⏱ 👆 ⚖️ 💅 🔃 `__init__`, 👥 🔜 ⚙️ ⚫️ 🔗 👆 📟.

## ✍ 👐

👥 💪 ✍ 👐 👉 🎓 ⏮️:

from typing import List, Union

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):

from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int

```Python hl_lines="2  6"
{!../../docs_src/static_files/tutorial001.py!}
```

/// note | "技术细节"

你也可以用 `from starlette.staticfiles import StaticFiles`。

**FastAPI** 提供了和 `starlette.staticfiles` 相同的 `fastapi.staticfiles` ，只是为了方便你，开发者。但它确实来自Starlette。

///

### 什么是"挂载"(Mounting)

"挂载" 表示在特定路径添加一个完全"独立的"应用，然后负责处理所有子路径。

这与使用`APIRouter`不同，因为安装的应用程序是完全独立的。OpenAPI和来自你主应用的文档不会包含已挂载应用的任何东西等等。

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dataclasses.tutorial001 import app

client = TestClient(app)


def test_post_item():
    response = client.post("/items/", json={"name": "Foo", "price": 3})
    assert response.status_code == 200
    assert response.json() == {
        "name": "Foo",
        "price": 3,
        "description": None,
        "tax": None,
    }

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dependencies.tutorial004 import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        (
            "/items",
            200,
            {
                "items": [
                    {"item_name": "Foo"},
                    {"item_name": "Bar"},