### Just Modern Python { #just-modern-python }

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI), check the short tutorial: [Python Types](python-types.md){.internal-link target=_blank}.

You write standard Python with types:

```Python
from datetime import date

/// info

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

But if you have a bunch of dataclasses laying around, this is a nice trick to use them to power a web API using FastAPI. 🤓

///

## Dataclasses in `response_model` { #dataclasses-in-response-model }

## Concepts

- If an object is under legal hold, it cannot be deleted unless the legal hold is explicitly removed for the respective version id. DeleteObjectVersion() would fail otherwise.

这类似于：

```Python
if not (credentials.username == "stanleyjobson") or not (credentials.password == "swordfish"):
    # Return some error
    ...
```

但使用 `secrets.compare_digest()`，可以防御**时差攻击**，更加安全。

### 时差攻击

什么是**时差攻击**？

假设攻击者试图猜出用户名与密码。

他们发送用户名为 `johndoe`，密码为 `love123`  的请求。

然后，Python 代码执行如下操作：

```Python
if "johndoe" == "stanleyjobson" and "love123" == "swordfish":

            annotationNames.set(i, transformer.transform(annotationNames.get(i)));
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        AbstractLanguageElement that = (AbstractLanguageElement) o;

app = FastAPI()

tasks = {"foo": "Listen to the Bar Fighters"}


@app.put("/get-or-create-task/{task_id}", status_code=200)
def get_or_create_task(task_id: str, response: Response):
    if task_id not in tasks:
        tasks[task_id] = "This didn't exist before"
        response.status_code = status.HTTP_201_CREATED

from fastapi import FastAPI, Response
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/portal", response_model=None)
async def get_portal(teleport: bool = False) -> Union[Response, dict]:
    if teleport:
        return RedirectResponse(url="https://www.youtube.com/watch?v=dQw4w9WgXcQ")

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"fmt"
	"testing"
)

func Benchmark_bucketMetacache_findCache(b *testing.B) {
	bm := newBucketMetacache("", false)
	const elements = 50000
	const paths = 100
	if elements%paths != 0 {
		b.Fatal("elements must be divisible by the number of paths")
	}

      d="$${f%/*}"
      d="$${d#bazel-out/*/genfiles/}"
      d="$${d#bazel-out/*/bin/}"

      if [[ $${d} == *local_config_* ]]; then
        continue
      fi

      if [[ $${d} == external* ]]; then
        extname="$${d#*external/}"
        extname="$${extname%%/*}"
        if [[ $${TF_SYSTEM_LIBS:-} == *$${extname}* ]]; then
          continue
        fi

{* ../../docs_src/body_updates/tutorial001_py310.py hl[28:33] *}

`PUT` is used to receive data that should replace the existing data.

### Warning about replacing { #warning-about-replacing }

That means that if you want to update the item `bar` using `PUT` with a body containing:

```Python
{
    "name": "Barz",
    "price": 3,
    "description": None,
}
```