你应该使用HTTPX https://www.python-httpx.org/图书馆，其中提供了一个async API https://www.python-httpx.org/async/。如中所述这个答案 https://stackoverflow.com/a/73736138/17865804，你产生一个Client并在每次需要时重复使用它。使异步请求HTTPX https://www.python-httpx.org/async/#making-async-requests，你需要一个AsyncClient https://github.com/encode/httpx/blob/71ee50b27770b461a5d2aaba9fca1fbc261bede1/httpx/_client.py#L1297.
您还可以使用以下命令控制连接池的大小limits的关键字参数Client，它以httpx.Limits https://github.com/encode/httpx/blob/9e97d7d42963e408ef2949cc86515d6025dbec24/httpx/_config.py#L276。例如：
limits = httpx.Limits(max_keepalive_connections=5, max_connections=10)
client = httpx.AsyncClient(limits=limits)
您可以根据您的需要调整以上内容。根据文档池限制配置 https://www.python-httpx.org/advanced/#pool-limit-configuration:
-
max_keepalive_connections，允许的保持活动连接数，或None总是允许。 （默认值20)
-
max_connections，允许的最大连接数，或None没有任何限制。 （默认100)
-
keepalive_expiry，空闲保持活动连接的时间限制（以秒为单位），或者None没有任何限制。 （默认5)
如果你愿意调整超时时间 https://www.python-httpx.org/advanced/#timeout-configuration同样，您可以使用timeout参数来设置单个请求或一个请求的超时Client/AsyncClient实例，这会导致给定的超时被用作此客户端发出的请求的默认超时（请参阅实现Timeout https://github.com/encode/httpx/blob/9baf3a6cd2fa9ebeb17dba5a3e5c6e9e0af83a96/httpx/_config.py#L189类也是如此）。您可以详细指定超时行为；例如，设置readtimeout 参数将指定等待接收数据块（即响应正文的块）的最大持续时间。如果HTTPX在此时间范围内无法接收数据，ReadTimeout引发异常。如果设置为None而不是一些正数值，不会有timeout on read。默认为 5 秒timeout关于所有操作。
您可以使用await client.aclose() to 显式关闭AsyncClient https://www.python-httpx.org/async/#opening-and-closing-clients当你完成它时（这可以在一个关闭事件 https://fastapi.tiangolo.com/advanced/events/#shutdown-event例如，处理程序）。
To 运行多个异步操作— 由于您需要请求五个不同的 URL，因此当您的 API 端点被调用时 — 您可以使用等待的 asyncio.gather() https://docs.python.org/3/library/asyncio-task.html#asyncio.gather。它将执行async操作并以相同的顺序返回结果列表可等待的事情 https://docs.python.org/3/library/asyncio-task.html#awaitables (tasks）被传递给该函数。
工作示例：
from fastapi import FastAPI
import httpx
import asyncio
URLS = ['https://www.foxnews.com/',
'https://edition.cnn.com/',
'https://www.nbcnews.com/',
'https://www.bbc.co.uk/',
'https://www.reuters.com/']
limits = httpx.Limits(max_keepalive_connections=5, max_connections=10)
timeout = httpx.Timeout(5.0, read=15.0) # 15s timeout on read. 5s timeout elsewhere.
client = httpx.AsyncClient(limits=limits, timeout=timeout)
app = FastAPI()
@app.on_event('shutdown')
async def shutdown_event():
await client.aclose()
async def send(url, client):
return await client.get(url)
@app.get('/')
async def main():
tasks = [send(url, client) for url in URLS]
responses = await asyncio.gather(*tasks)
# for demo purposes, return only the first 50 chars of each response
return [r.text[:50] for r in responses]
如果你愿意避免将整个响应正文读入 RAM，你可以使用流式响应 https://www.python-httpx.org/async/#streaming-responses，如中所述这个答案 https://stackoverflow.com/a/73770074/17865804并演示如下：
from fastapi import FastAPI
from fastapi.responses import StreamingResponse
import httpx
import asyncio
URLS = ['https://www.foxnews.com/',
'https://edition.cnn.com/',
'https://www.nbcnews.com/',
'https://www.bbc.co.uk/',
'https://www.reuters.com/']
limits = httpx.Limits(max_keepalive_connections=5, max_connections=10)
timeout = httpx.Timeout(5.0, read=15.0) # 15s timeout on read. 5s timeout elsewhere.
client = httpx.AsyncClient(limits=limits, timeout=timeout)
app = FastAPI()
@app.on_event('shutdown')
async def shutdown_event():
await client.aclose()
async def send(url, client):
req = client.build_request('GET', url)
return await client.send(req, stream=True)
async def iter_content(responses):
for r in responses:
async for chunk in r.aiter_text():
# for demo purposes, return only the first 50 chars of each response
yield chunk[:50]
yield '\n\n'
break
await r.aclose()
@app.get('/')
async def main():
tasks = [send(url, client) for url in URLS]
responses = await asyncio.gather(*tasks)
return StreamingResponse(iter_content(responses), media_type='text/event-stream')
