NAME

IO::AIO::Promiser - Promise interface around IO::AIO

SYNOPSIS

(This example uses AnyEvent::AIO for conciseness; it’s not difficult to adapt it for use with, e.g., IO::Async or Mojolicious.)

To slurp with AnyEvent and Promise::AsyncAwait:

use AnyEvent::AIO;
use Promise::AsyncAwait;

use IO::AIO::Promiser ':all';

async sub slurp ($abs_path) {
    my $fh = await aio_open($abs_path, Fcntl::O_RDONLY, 0);

    my $buf = q<>;
    1 while await aio_read($fh, undef, 65536, $buf, length $buf);

    return $buf;
}

… and now you can:

my $cv = AnyEvent->condvar();

slurp("/etc/services")->then(
    sub { $cv->(@_) },
    sub { $cv->croak(@_) },
);

my $content = $cv->recv();

It’s a bit like Coro::AIO, but with async/await rather than Coro, and more proactive error-checking.

See below for examples of setup with IO::Async and Mojolicious.

DESCRIPTION

IO::AIO is great, but its callback-driven interface is less so. This module wraps IO::AIO so you can easily use promises with it instead.

FUNCTIONS

This module doesn’t (yet?) cover everything IO::AIO can do. If there’s functionality you’d like to have, create a feature request.

The following are like their IO::AIO counterparts, but the final callback argument is omitted, and a promise is returned instead. That promise’s resolution is the callback’s success-case return, and the rejection is the callback’s failure-case return.

• wd and realpath()
• open() (NB: The resolution is an oddity: a filehandle that is not a GLOB reference.)
• seek()
• close()
• read() and write()
• readdir() and readdirx()
• stat() and lstat()
• mkdir() and rmdir()
• chown() and chmod()
• utime()
• unlink()
• link(), symlink(), and readlink()
• rename() and rename2()

The following are a bit different—but with good reason!—from the corresponding IO::AIO interface:

• slurp() - The promise resolves to the file content, so you don’t need to initialize a separate $data scalar.

EXPORT INTERFACE

Since it’s clunky to have to type IO::AIO::Promiser::open, if you pass :all to this module on import you’ll get aio_* aliases exported into your namespace, so you can call, e.g., aio_open instead. This matches IO::AIO’s own calling convention.

AUTHOR & COPYRIGHT

Copyright 2021 Gasper Software Consulting

LICENSE

This library is licensed under the same license as Perl.