And it shows their true commitment to FastAPI and its **community** (you), as they not only want to provide you a **good service** but also want to make sure you have a **good and healthy framework**, FastAPI. 🙇

For example, you might want to try <a href="https://speakeasyapi.dev/?utm_source=fastapi+repo&utm_medium=github+sponsorship" class="external-link" target="_blank">Speakeasy</a>.

# Development - Contributing

First, you might want to see the basic ways to [help FastAPI and get help](help-fastapi.md){.internal-link target=_blank}.

## Developing

If you already cloned the <a href="https://github.com/tiangolo/fastapi" class="external-link" target="_blank">fastapi repository</a> and you want to deep dive in the code, here are some guidelines to set up your environment.

### Virtual environment with `venv`

```Python
burgers = await get_burgers(2)
```

The key here is the `await`. It tells Python that it has to wait ⏸ for `get_burgers(2)` to finish doing its thing 🕙 before storing the results in `burgers`. With that, Python will know that it can go and do something else 🔀 ⏯ in the meanwhile (like receiving another request).

The tabs will wait for a bit and then some of them will show `Internal Server Error`.

### What happens

The first tab will make your app create a connection to the database and wait for some seconds before replying back and closing the database connection.

Then, for the request in the next tab, your app will wait for one second less, and so on.

## Previous Steps Before Starting

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.

So, you will want to have a **single process** to perform those **previous steps**, before starting the application.

async def index(websocket: WebSocket, deps: DepList):
    await websocket.accept()
    await websocket.send_text(json.dumps(deps))
    await websocket.close()


@router.websocket("/router", dependencies=[create_dependency("routerindex")])
async def routerindex(websocket: WebSocket, deps: DepList):
    await websocket.accept()
    await websocket.send_text(json.dumps(deps))
    await websocket.close()

import * as fs from 'fs'

async function modifyOpenAPIFile(filePath) {
  try {
    const data = await fs.promises.readFile(filePath)
    const openapiContent = JSON.parse(data)

    const paths = openapiContent.paths
    for (const pathKey of Object.keys(paths)) {
      const pathData = paths[pathKey]
      for (const method of Object.keys(pathData)) {
        const operation = pathData[method]
        if (operation.tags && operation.tags.length > 0) {

* `seek(offset)`: 파일 내 `offset`(`int`) 위치의 바이트로 이동합니다.
    * 예) `await myfile.seek(0)` 를 사용하면 파일의 시작부분으로 이동합니다.
    * `await myfile.read()` 를 사용한 후 내용을 다시 읽을 때 유용합니다.
* `close()`: 파일을 닫습니다.

상기 모든 메소드들이 `async` 메소드이기 때문에 “await”을 사용하여야 합니다.

예를들어, `async` *경로 작동 함수*의 내부에서 다음과 같은 방식으로 내용을 가져올 수 있습니다:

```Python
contents = await myfile.read()
```

        "requestBody": {
            "content": {"application/x-yaml": {"schema": Item.model_json_schema()}},
            "required": True,
        },
    },
)
async def create_item(request: Request):
    raw_body = await request.body()
    try:
        data = yaml.safe_load(raw_body)
    except yaml.YAMLError:
        raise HTTPException(status_code=422, detail="Invalid YAML")
    try:
        item = Item.model_validate(data)

* `read(size)`: ✍ `size` (`int`) 🔢/🦹 📁.
* `seek(offset)`: 🚶 🔢 🧘 `offset` (`int`) 📁.
    * 🤶 Ⓜ., `await myfile.seek(0)` 🔜 🚶 ▶️ 📁.
    * 👉 ✴️ ⚠ 🚥 👆 🏃 `await myfile.read()` 🕐 & ⤴️ 💪 ✍ 🎚 🔄.
* `close()`: 🔐 📁.

🌐 👫 👩‍🔬 `async` 👩‍🔬, 👆 💪 "⌛" 👫.

🖼, 🔘 `async` *➡ 🛠️ 🔢* 👆 💪 🤚 🎚 ⏮️:

```Python
contents = await myfile.read()
```

🚥 👆 🔘 😐 `def` *➡ 🛠️ 🔢*, 👆 💪 🔐 `UploadFile.file` 🔗, 🖼: