In FastAPI, using `async` functions is optional, but it provides certain advantages, especially in scenarios where your application may need to handle multiple concurrent operations without blocking the execution of other tasks. The use of `async` is closely tied to asynchronous programming in Python, often referred to as asyncio.
Here are some reasons why you might choose to use `async` functions in FastAPI:
1. Concurrent Operations:
- Async functions allow your application to handle multiple operations concurrently without waiting for each operation to complete before moving on to the next one.
- This can be beneficial for I/O-bound operations like making multiple API requests, database queries, or other network-related tasks.
2. Improved Performance:
- Asynchronous programming can improve the overall performance of your application, especially in scenarios where there are many I/O-bound tasks.
- Instead of waiting for one task to complete before starting the next one, async functions can switch between tasks during I/O operations, making more efficient use of resources.
3. Scalability:
- Asynchronous programming can lead to better scalability in applications that require handling a large number of simultaneous connections or requests.
- It's well-suited for building scalable web servers and APIs that need to handle a high volume of requests concurrently.
4. Non-Blocking Operations:
- Async functions in FastAPI enable non-blocking behavior, allowing the application to continue processing other tasks while waiting for I/O operations to complete.
- This is particularly useful for scenarios where you want to keep the application responsive and handle multiple requests simultaneously.
Here's an example of an async function in FastAPI:
```python
from fastapi import FastAPI
import httpx
app = FastAPI()
async def fetch_data():
async with httpx.AsyncClient() as client:
response = await client.get("https://example.com")
return response.text
@app.get("/")
async def read_data():
data = await fetch_data()
return {"data": data}
```
In this example, the `fetch_data` function is an async function that makes an asynchronous HTTP request using the `httpx` library. The `read_data` endpoint calls this async function using `await` to asynchronously fetch data without blocking the entire application.
