🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip

🥈 ❌ <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 🔢 💲 📨.

🚥 🚫 🚚, ⚫️ `None` 🔢, 📥 👥 🚚 `"World"` 🔢 💲 ⚙️.

///

⤴️ 👆 💪 🤙 👈 🐍 📋:

<div class="termy">

#!/bin/bash

export CGO_ENABLED=0
for dir in docs/debugging/*/; do
	bin=$(basename ${dir})
	go build -C ${dir} -o ${PWD}/${bin}

.ipynb_checkpoints
.mypy_cache
.vscode
__pycache__
.pytest_cache
htmlcov
dist
site
.coverage*
coverage.xml
.netlify
test.db
log.txt
Pipfile.lock
env3.*
env
docs_build
site_build
venv
docs.zip
archive.zip

# vim temporary files
*~
.*.sw?
.cache

# macOS

# CORS (Cross-Origin Resource Sharing)

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS or "Cross-Origin Resource Sharing"</a> refers to the situations when a frontend running in a browser has JavaScript code that communicates with a backend, and the backend is in a different "origin" than the frontend.

## Origin

/// check | "检查"

**FastAPI** 使用 Python 类型声明实现了数据校验。

注意，上面的错误清晰地指出了未通过校验的具体原因。

这在开发调试与 API 交互的代码时非常有用。

///

## 查看文档

访问 <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>，查看自动生成的 API 文档：

<img src="/img/tutorial/path-params/image01.png">

/// check | "检查"

还是使用 Python 类型声明，**FastAPI** 提供了（集成 Swagger UI 的）API 文档。

注意，路径参数的类型是整数。

///

here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret certSecret: "" publicCrt: public.crt privateKey: private.key ## Trusted Certificates Settings for MinIO. Ref: https://docs.minio.io/docs/how-to-secure-access-to-minio-server-with-tls#install-certificates-from-third-party-cas ## Bundle multiple trusted certificates into one secret and pass that here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret ## When...

here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret certSecret: "" publicCrt: public.crt privateKey: private.key ## Trusted Certificates Settings for MinIO. Ref: https://docs.minio.io/docs/how-to-secure-access-to-minio-server-with-tls#install-certificates-from-third-party-cas ## Bundle multiple trusted certificates into one secret and pass that here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret ## When...

* Der _Pfad_ `/items/{item_id}` hat einen optionalen `str` _Query Parameter_ `q`.

### Interaktive API-Dokumentation

Gehen Sie nun auf <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

Sie sehen die automatische interaktive API-Dokumentation (bereitgestellt von <a href="https://github.com/swagger-api/swagger-ui" class="external-link" target="_blank">Swagger UI</a>):

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/python_types/tutorial011.py!}
```

////

/// info

To learn more about <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic, check its docs</a>.

///

**FastAPI** is all based on Pydantic.

* Designed around these standards, after a meticulous study. Instead of an afterthought layer on top.
* This also allows using automatic **client code generation** in many languages.

### Automatic docs

Interactive API documentation and exploration web user interfaces. As the framework is based on OpenAPI, there are multiple options, 2 included by default.