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=head1 NAME

Geo::Coder::List - Call many Geo-Coders

=head1 VERSION

Version 0.36

=cut

=head1 SYNOPSIS

L<Geo::Coder::All>
and
L<Geo::Coder::Many>
are great routines but neither quite does what I want.

C<Geo::Coder::List> is designed to simplify geocoding tasks by aggregating multiple geocoding services into a single, unified interface.
It allows developers to chain and prioritize various geocoding backends (such as Google Places, OpenStreetMap, and GeoNames)
based on specific conditions,
such as location or usage limits.
The module features built-in caching mechanisms to optimize performance and reduce redundant API calls,
while also normalizing responses from different providers into a consistent format for easier integration with mapping systems such as L<HTML::OSM> and <L<HTML::GoogleMaps::V3>.

=head1 SUBROUTINES/METHODS

=head2 new

Creates a C<Geo::Coder::List> object.

Takes an optional argument C<cache> which is a reference to a HASH or an object that supports C<get()> and C<set()> methods.
The licences of some geo coders,
such as Google,
specifically prohibit caching API calls,
so be careful to only use those services that allow it.

Takes an optional argument C<debug>,
the higher the number,
the more debugging.

    use Geo::Coder::List;
    use CHI;

    my $geocoder->new(cache => CHI->new(driver => 'Memory', global => 1));

The class can be configured at runtime using environments and configuration files,
for example,
setting C<$ENV{'GEO__CODER__LIST__carp_on_warn'}> causes warnings to use L<Carp>.
For more information about configuring object constructors at runtime,
see L<Object::Configure>.

=cut

=head2 push($self, $geocoder)

Add an encoder to the list of encoders.

    use Geo::Coder::List;
    use Geo::Coder::GooglePlaces;
    # ...
    my $list = Geo::Coder::List->new()->push(Geo::Coder::GooglePlaces->new());

Different encoders can be preferred for different locations.
For example, this code uses geocode.ca for Canada and US addresses,
and OpenStreetMap for other places:

    my $geo_coderlist = Geo::Coder::List->new()
        ->push({ regex => qr/(Canada|USA|United States)$/, geocoder => Geo::Coder::CA->new() })
        ->push(Geo::Coder::OSM->new());

    # Uses Geo::Coder::CA, and if that fails, uses Geo::Coder::OSM
    my $location = $geo_coderlist->geocode(location => '1600 Pennsylvania Ave NW, Washington DC, USA');
    # Only uses Geo::Coder::OSM
    if($location = $geo_coderlist->geocode('10 Downing St, London, UK')) {
        print 'The prime minister lives at co-ordinates ',
            $location->{geometry}{location}{lat}, ',',
            $location->{geometry}{location}{lng}, "\n";
    }

    # It is also possible to limit the number of enquires used by a particular encoder
    $geo_coderlist->push({ geocoder => Geo::Coder::GooglePlaces->new(key => '1234', limit => 100) });

=head3 Parameters

=over 4

=item * C<$geocoder> hashref (required)

Hashref containing a regex and a geocoding object.

=back

=cut

=head2 geocode

Runs geocode on all of the loaded drivers.
See L<Geo::Coder::GooglePlaces::V3> for an explanation.

The name of the Geo-Coder that gave the result is put into the geocode element of the
return value,
if the value was retrieved from the cache the value will be undefined.

    if(defined($location->{'geocoder'})) {
        print 'Location information retrieved using ', $location->{'geocoder'}, "\n";
    }

=cut

=head2 ua($self, $ua)

Accessor method to set the UserAgent object used internally by each of the Geo-Coders.
You can call I<env_proxy>,
for example,
to set the proxy information from environment variables:

    my $geocoder_list = Geo::Coder::List->new();
    my $ua = LWP::UserAgent->new();
    $ua->env_proxy(1);
    $geocoder_list->ua($ua);

Note that unlike Geo::Coders,
there is no read method since that would be pointless.

=head3 Parameters

=over 4

=item * C<$ua> object (optional)

Useragent object.

=back

=cut

=head2 reverse_geocode

Similar to geocode except it expects a latitude/longitude parameter.

    print $geocoder_list->reverse_geocode(latlng => '37.778907,-122.39732');

=cut

=head2 log

Returns the log of events to help you debug failures,
optimize lookup order and fix quota breakage.

    my @log = @{$geocoderlist->log()};

=cut

=head2 flush

Clear the log.

=cut

=head1 AUTHOR

Nigel Horne, C<< <njh at nigelhorne.com> >>

=head1 BUGS

Please report any bugs or feature requests to C<bug-geo-coder-list at rt.cpan.org>,
or through the web interface at
L<https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Geo-Coder-List>.
I will be notified, and then you'll
automatically be notified of progress on your bug as I make changes.

reverse_geocode() doesn't update the logger.
reverse_geocode() should support L<Geo::Location::Point> objects.

=head1 SEE ALSO

=over 4

=item * Test coverage report: L<https://nigelhorne.github.io/Geo-Coder-List/coverage/>

=item * L<Geo::Coder::All>

=item * L<Geo::Coder::GooglePlaces>

=item * L<Geo::Coder::Many>

=item * L<Object::Configure>

=back

=cut

=head1 SUPPORT

This module is provided as-is without any warranty.

You can find documentation for this module with the perldoc command.

    perldoc Geo::Coder::List

You can also look for information at:

=over 4

=item * RT: CPAN's request tracker

L<https://rt.cpan.org/NoAuth/Bugs.html?Dist=Geo-Coder-List>

=item * MetaCPAN

L<https://metacpan.org/release/Geo-Coder-List>

=back

=head1 LICENSE AND COPYRIGHT

Copyright 2016-2026 Nigel Horne.

This program is released under the following licence: GPL2

=cut