Python 3.4 中的“异步”

Question

asyncssh 入门文档给出了以下 hello 示例：

import asyncio, asyncssh, sys

async def run_client():
    async with asyncssh.connect('localhost') as conn:
        result = await conn.run('echo "Hello!"', check=True)
        print(result.stdout, end='')

try:
    asyncio.get_event_loop().run_until_complete(run_client())
except (OSError, asyncssh.Error) as exc:
    sys.exit('SSH connection failed: ' + str(exc))

但是，这不会运行，因为 Python 3.4 不支持异步：

async with asyncssh.connect('localhost', username='squirtle', password='xxxxxxxxxxxx') as conn:
     ^

Answer 1

我去做了，这对我有用。

@asyncio.coroutine
def run_client():
        with(yield from asyncssh.connect('localhost', username='root', password='xxxxxxxx')) as conn:
                result = yield from conn.run('ls', check=True)
                print(result.stdout, end='')

Answer 2

async关键字是在Python3.5中引入的，你应该在早期版本中使用asyncio.corutine。

勾选PEP492 and Python 3.5 release notes

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Python 3.4 中的“异步”

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