Mojolicious::Plugin::GoogleCalc - currency converter with cache

gistfile1.pl

package Mojolicious::Plugin::GoogleCalc;

use Mojo::Base 'Mojolicious::Plugin';

use Mojo::ByteStream;
use Mojo::Loader;
use Mojo::JSON 'j';
use Mojo::ByteStream 'b';
use Mojo::UserAgent;

use strict;

my $app=undef;
my $c=undef;
my $conf=undef;

sub register {
    my ($self, $app_param, $args) = @_;

    $app=$app_param;

    $conf=$args;

    $app->helper(

        'google_calc' => sub {
            my $self       = shift;
            my $class_name = shift;

            $class_name ||= 'Mojolicious::Plugin::GoogleCalc';

            unless ($class_name =~ m/[A-Z]/) {
                my $namespace = ref($self->app) . '::';
                $namespace = '' if $namespace =~ m/^Mojolicious::Lite/;

                $class_name = join '' => $namespace, Mojo::ByteStream->new($class_name)->camelize;
            }

            my $e = Mojo::Loader->new->load($class_name);

            Carp::croak qq/Can't load validator '$class_name': / . $e->message if ref $e;
            Carp::croak qq/Can't find validator '$class_name'/ if $e;
            Carp::croak qq/Wrong validator '$class_name' isa/ unless $class_name->isa($class_name);

            return $class_name->new(%$conf, @_);
        }
    );
}

sub convert_currency {
    my $self = shift;
    my ($params)=@_;

    $params={} unless (ref $params eq 'HASH');

    my $response_json=undef;

    my $cache=undef;

    $self->{conf}=$conf;

    if ($self->{conf}->{cache_file}) {
        unless (-f $self->{conf}->{cache_file}) {
            warn "Creating cache file: $self->{conf}->{cache_file}" if ($params->{debug});
            open(CACHE_FILE,">$self->{conf}->{cache_file}");
            close(CACHE_FILE);
        }
        use Cache::FastMmap;
        $cache = Cache::FastMmap->new(
            share_file => $self->{conf}->{cache_file},
            expire_time => $self->{conf}->{cache_expire_time} || 3600 * 6,
        );
        $response_json=$cache->get('convert_curency:response:'.$params->{from}.":".$params->{to});
        warn "Cache content:" if ($params->{debug});
        warn $app->dumper( $response_json ) if ($params->{debug});
    }

    unless ($response_json) {
        warn "Will retrieve data from Google" if ($params->{debug});
        my $calc_url='http://www.google.com/ig/calculator'
            ."?q=1".$params->{from}."=?".$params->{to};
        my $ua = Mojo::UserAgent->new;
        $ua->max_redirects(5);
        my $google_response = $ua->get($calc_url)->res->body;

        my $google_response_fixed = $google_response;
        $google_response_fixed =~s!([,{]{1})(\S+?)\:!$1"$2":!isg;
        $response_json=j($google_response_fixed);

        $response_json->{ratio}=$response_json->{rhs};
        $response_json->{ratio}=~s!\s.+$!!;

        if ($cache) {
            $cache->set('convert_curency:response:'.$params->{from}.":".$params->{to}, $response_json);
            warn "Data cached" if ($params->{debug});
        }
    }

    $response_json->{amount}=$response_json->{ratio}*$params->{amount};

    warn "Full data: " if ($params->{debug});
    warn $app->dumper( $response_json ) if ($params->{debug});

    return $response_json->{amount};
}


1;

=comment

    $self->plugin('GoogleCalc', {
        cache_file => '/tmp/razdalje_google_calc.shm', # optional, requires Cache::FastMmap;
        expire_time => 3600 * 6, # optional
    });

    $self->google_calc->convert_currency({ from=>'USD', to=>'EUR', amount=>123, debug=>1 });

=cut