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lib/Amazon/DynamoDB/Simple.pm  view on Meta::CPAN

    # sync from $dynamodb1 -> $dynamodb0
    $self->_sync_items($dynamodb1 => $dynamodb0, $items1 => $items0);
}

sub _process_items {
    my ($self, $items) = @_;

    my $key = $self->primary_key;
    my $definitions;

    for my $item (@$items) {
        my $primary_key = delete($item->{$key})->{S};

        for my $attr (keys %$item) {
            my $type_value = $item->{$attr};
            my ($type) = keys %$type_value;
            $definitions->{$primary_key}->{$attr} = $item->{$attr}->{$type};
        }

        $definitions->{$primary_key}->{$key} = $primary_key;
    }


    return $definitions;
}

sub _sync_items {
    my ($self, $from_ddb, $to_ddb, $from_items, $to_items) = @_;

    my $primary_key_name = $self->primary_key;

    for my $from_key (keys %$from_items) {
        my $from_value = $from_items->{$from_key};
        my $to_value = $to_items->{$from_key};
        if (!$to_value) {
            $to_value = {last_updated => '1900-01-01T00:00:00'};
            $to_items->{$from_key} = $to_value;
        }

        my $updated0 = $from_value->{last_updated};
        my $updated1 = $to_value->{last_updated};

        # don't need to sync if the items are the same age and not deleted
        next if $updated0 eq $updated1 && !$to_value->{deleted};

        # find the newest item
        my $newest = $updated0 gt $updated1
            ? $from_value
            : $to_value;

        # sync newest item to the other region
        if ($newest->{deleted}) {
            $self->permanent_delete( $newest->{$primary_key_name} );
        }
        else {
            # TODO: this could be more efficient by syncing to just the ddb
            # that needs it
            $self->put(%$newest);
        }

        # Lets say we are syncing from $dynamodb0 -> $dynamodb1. This prevents
        # us from re syncing this item when we sync in the other direction from
        # $dynamodb1 -> $dynamodb0
        $to_value->{last_updated} = $from_value->{last_updated};
    }
}

sub items {
    my ($self) = @_;

    my $human_items = {};

    my $items = $self->scan->{Items};
    my $primary_key_name = $self->primary_key;

    # convert $items to something more human readable
    for my $item (@$items) {
        my $primary_key = delete($item->{$primary_key_name})->{S};

        for my $attr (keys %$item) {
            my $type_value = $item->{$attr};
            my ($type) = keys %$type_value;
            $human_items->{$primary_key}->{$attr} = $item->{$attr}->{$type};
        }

        # inflate json values
        my $new_item                 = $human_items->{$primary_key};
        my %inflated_item            = $self->inflate(%$new_item);
        $human_items->{$primary_key} = \%inflated_item;

        delete $human_items->{$primary_key}
            if $human_items->{$primary_key}->{deleted};
    }

    return %$human_items;
}

sub keys {
    my ($self) = @_;
    my %items = $self->items;
    return keys %items;
}

1;
__END__

=head1 ACKNOWLEDGEMENTS

Thanks to L<DuckDuckGo|http://duckduckgo.com> for making this module possible by donating developer time.

=head1 LICENSE

Copyright (C) Eric Johnson.

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

=head1 AUTHOR

Eric Johnson E<lt>eric.git@iijo.orgE<gt>