PYTHON

python async await

import asyncio

async def print_B(): #Simple async def
    print("B")

async def main_def():
    print("A")
    await asyncio.gather(print_B())
    print("C")
asyncio.run(main_def())

# The function you wait for must include async
# The function you use await must include async
# The function you use await must run by asyncio.run(THE_FUNC())

python async function

import asyncio


async def eternity():
   # Sleep for 60 minutes
   await asyncio.sleep(3600)
   print('yay!')


async def main():
   try:
       # timeout if function takes longer than 1 second
       await asyncio.wait_for(eternity(), timeout=1.0)
   except asyncio.TimeoutError:
       print('timeout!')


asyncio.run(main())

# output timeout!

python async function

import asyncio
import time


async def say_after(delay, msg):
   """
   :param delay: how many seconds to delay
   :param msg: message to print to console
   :return: msg
   """
   await asyncio.sleep(delay)
   print(msg)
   return msg


async def main():
   print(f"started at {time.strftime('%X')}")
   # execute async functions concurrently and return the results as a list
   results = await asyncio.gather(say_after(delay=3, msg='hello'), say_after(delay=1, msg='world'))
   print(f"finished at {time.strftime('%X')}")
   print(f"Results of async gather {results}")

# run async main function
asyncio.run(main())

# output
# started at 16:57:46
# world
# hello
# finished at 16:57:49
# Results of async gather ['hello', 'world']

python async function

import asyncio
import time


async def say_after(delay, msg):
   """
   :param delay: how many seconds to delay
   :param msg: message to print to console
   :return: None
   """
   await asyncio.sleep(delay)
   print(msg)


async def main():
   print(f"started at {time.strftime('%X')}")
   # execute async functions in order
   await say_after(delay=3, msg='hello')
   await say_after(delay=2, msg='world')

   print(f"finished at {time.strftime('%X')}")

# run async main function
asyncio.run(main())

# output
# started at 16:47:08
# hello
# world
# finished at 16:47:13

async, await, python

async def get_chat_id(name):
    await asyncio.sleep(3)
    return "chat-%s" % name

async def main():
    id_coroutine = get_chat_id("django")
    result = await id_coroutine

python async await

import asyncio
from PIL import Image
import urllib.request as urllib2

async def getPic(): #Proof of async def
    pic = Image.open(urllib2.urlopen("https://c.files.bbci.co.uk/E9DF/production/_96317895_gettyimages-164067218.jpg"))
    return pic

async def main_def():
    print("A")
    print("Must await before get pic0...")
    pic0 = await asyncio.gather(getPic())
    print(pic0)
asyncio.run(main_def())

python async await function

async def sleep():
    print(f'Time: {time.time() - start:.2f}')
    await asyncio.sleep(1)

python async await function await expression

import asyncio
import time

from asgiref.sync import sync_to_async


def blocking_function(seconds: int) -> str:
    time.sleep(seconds)
    return f"Finished in {seconds} seconds"

async def main():
    seconds_to_sleep = 5
    function_message = await sync_to_async(blocking_function)(seconds_to_sleep)
    print(function_message)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())
loop.close()