python flask 路由_从Flask路由进行Python异步调用

你的名字 2023-01-09 01:22 259阅读 0赞

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I want to execute an async function every time the Flask route is executed. Why is the abar function never executed?

import asyncio

from flask import Flask

async def abar(a):

print(a)

loop = asyncio.get\_event\_loop()

app = Flask(\_\_name\_\_)

@app.route("/")

def notify():

asyncio.ensure\_future(abar("abar"), loop=loop)

return "OK"

if \_\_name\_\_ == "\_\_main\_\_":

app.run(debug=False, use\_reloader=False)

loop.run\_forever()

I also tried putting the blocking call in a separate thread. But it is still not calling the abar function.

import asyncio

from threading import Thread

from flask import Flask

async def abar(a):

print(a)

app = Flask(\_\_name\_\_)

def start\_worker(loop):

asyncio.set\_event\_loop(loop)

try:

loop.run\_forever()

finally:

loop.close()

worker\_loop = asyncio.new\_event\_loop()

worker = Thread(target=start\_worker, args=(worker\_loop,))

@app.route("/")

def notify():

asyncio.ensure\_future(abar("abar"), loop=worker\_loop)

return "OK"

if \_\_name\_\_ == "\_\_main\_\_":

worker.start()

app.run(debug=False, use\_reloader=False)

解决方案

You can incorporate some async functionality into Flask apps without having to completely convert them to asyncio.

import asyncio

from flask import Flask

async def abar(a):

print(a)

loop = asyncio.get\_event\_loop()

app = Flask(\_\_name\_\_)

@app.route("/")

def notify():

loop.run\_until\_complete(abar("abar"))

return "OK"

if \_\_name\_\_ == "\_\_main\_\_":

app.run(debug=False, use\_reloader=False)

This will block the Flask response until the async function returns, but it still allows you to do some clever things. I've used this pattern to perform many external requests in parallel using aiohttp, and then when they are complete, I'm back into traditional flask for data processing and template rendering.

import aiohttp

import asyncio

import async\_timeout

from flask import Flask

loop = asyncio.get\_event\_loop()

app = Flask(\_\_name\_\_)

async def fetch(url):

async with aiohttp.ClientSession() as session, async\_timeout.timeout(10):

async with session.get(url) as response:

return await response.text()

def fight(responses):

return "Why can't we all just get along?"