This module is an implementation of the "Promise/A+" pattern for asynchronous programming. Promises are meant to be a way to better deal with the resulting callback spaghetti that can often result in asynchronous programs.

use AnyEvent::HTTP;
use JSON::XS qw[ decode_json ];
use Promises qw[ collect deferred ];

sub fetch_it {
    my ($uri) = @_;
    my $d = deferred;
    http_get $uri => sub {
        my ($body, $headers) = @_;
        $headers->{Status} == 200
            ? $d->resolve( decode_json( $body ) )
            : $d->reject( $body )
    };
    $d->promise;
}

my $cv = AnyEvent->condvar;

collect(
    fetch_it('http://rest.api.example.com/-/product/12345'),
    fetch_it('http://rest.api.example.com/-/product/suggestions?for_sku=12345'),
    fetch_it('http://rest.api.example.com/-/product/reviews?for_sku=12345'),
)->then(
    sub {
        my ($product, $suggestions, $reviews) = @_;
        $cv->send({
            product     => $product,
            suggestions => $suggestions,
            reviews     => $reviews,
        })
    },
    sub { $cv->croak( 'ERROR' ) }
);

my $all_product_info = $cv->recv;

To install this module from its CPAN tarball, type the following:

perl Makefile.PL make make test make install

If you cloned the github repo, the branch releases has the same code than the one living in CPAN, so the same Makefile dance will work. The master branch, however, needs to be built using Dist::Zilla:

dzil install

Be warned that the Dist::Zilla configuration is fine-tuned to my needs, so the dependency list to get it running is ludicrously huge. If you want a quick and dirty install, you can also do:

git checkout releases -- Makefile.PL
perl Makefile.PL
make test
make install

This module requires these other modules and libraries:

Test::More

This module optionally requires these other modules and libraries in order to support some specific features.

AnyEvent
Mojo::IOLoop
EV
IO::Async

• http://promises-aplus.github.io/promises-spec/

Copyright (C) 2012-2014 Infinity Interactive, Inc.

http://www.iinteractive.com

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.