[New-bugs-announce] [issue26270] Support for read()/write()/select() on asyncio

[Paulo Costa]

New submission from Paulo Costa:

I want to read from file descriptors from async coroutines.

I currently use `loop.add_reader(fd, callback)` and `loop.remove_reader(fd)`

It works, but IMO using callbacks feels completely alien in the middle of a coroutine.

I suggest adding new APIs to handle this. e.g.:
- asyncio.select(fd, mode)
- asyncio.read(fd, num)
- asyncio.write(fd, str)

(It would be nice to support all kinds of IO operations, but these are certainly the most important)

Using the current APIs, the async implementation of read() looks like this:

    async def async_read(fd. n):
        loop = asyncio.get_event_loop()
        future = asyncio.Future()

        def ready():
            future.set_result(os.read(fd, n))
            loop.remove_reader(fd)

        loop.add_reader(fd, ready)
        return future

----------
components: asyncio
messages: 259438
nosy: Paulo Costa, gvanrossum, haypo, yselivanov
priority: normal
severity: normal
status: open
title: Support for read()/write()/select() on asyncio
type: enhancement

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue26270>
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