### Create Pydantic *models* / schemas for reading / returning

Now create Pydantic *models* (schemas) that will be used when reading data, when returning it from the API.

For example, before creating an item, we don't know what will be the ID assigned to it, but when reading it (when returning it from the API) we will already know its ID.

### Creating the `Settings` only once with `lru_cache`

Reading a file from disk is normally a costly (slow) operation, so you probably want to do it only once and then re-use the same settings object, instead of reading it for each request.

But every time we do:

```Python
Settings()
```

* **Intuitive**: Great editor support. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> everywhere. Less time debugging.
* **Easy**: Designed to be easy to use and learn. Less time reading docs.
* **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
* **Robust**: Get production-ready code. With automatic interactive documentation.

### What are "Context Managers"

"Context Managers" are any of those Python objects that you can use in a `with` statement.

For example, <a href="https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">you can use `with` to read a file</a>:

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

🚥 👆 👟 ⚪️➡️ ➕1️⃣ 🔁 🛠️ 👈 🔨 🚫 👷 🌌 🔬 🔛 &amp; 👆 ⚙️ ⚖ 🙃 📊-🕴 *➡ 🛠️ 🔢* ⏮️ ✅ `def` 🤪 🎭 📈 (🔃 1️⃣0️⃣0️⃣ 💓), 🙏 🗒 👈 **FastAPI** ⭐ 🔜 🔄. 👫 💼, ⚫️ 👻 ⚙️ `async def` 🚥 👆 *➡ 🛠️ 🔢* ⚙️ 📟 👈 🎭 🚧 <abbr title="Input/Output: disk reading or writing, network communications.">👤/🅾</abbr>.

, 👯‍♂️ ⚠, 🤞 👈 **FastAPI** 🔜 [⏩](index.md#_15){.internal-link target=_blank} 🌘 (⚖️ 🌘 ⭐) 👆 ⏮️ 🛠️.

### 🔗

* **Intuitive**: Great editor support. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> everywhere. Less time debugging.
* **Easy**: Designed to be easy to use and learn. Less time reading docs.
* **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
* **Robust**: Get production-ready code. With automatic interactive documentation.

„Kontextmanager“ (Englisch „Context Manager“) sind bestimmte Python-Objekte, die Sie in einer `with`-Anweisung verwenden können.

Beispielsweise können Sie <a href="https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">`with` verwenden, um eine Datei auszulesen</a>:

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

gain (about 100 nanoseconds), please note that in **FastAPI** the effect would be quite opposite. In these cases, it's better to use `async def` unless your *path operation functions* use code that performs blocking <abbr title="Input/Output: disk reading or writing, network communications.">I/O</abbr>.

Still, in both situations, chances are that **FastAPI** will [still be faster](index.md#performance){.internal-link target=_blank} than (or at least comparable to) your previous framework....

### Что такое "контекстные менеджеры"

"Контекстные менеджеры" - это любые объекты Python, которые можно использовать в операторе `with`.

Например, <a href="https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">можно использовать `with` для чтения файла</a>:

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

## 上下文管理器

### 什么是“上下文管理器”

“上下文管理器”是您可以在`with`语句中使用的任何Python对象。

例如，<a href="https://docs.python.org/zh-cn/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">您可以使用`with`读取文件</a>：

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```