NAME

       CPAN::Mirrors - Get CPAN mirror information and select a fast one

SYNOPSIS

           use CPAN::Mirrors;

           my $mirrors = CPAN::Mirrors->new( $mirrored_by_file );

           my $seen = {};

           my $best_continent = $mirrors->find_best_continents( { seen => $seen } );
           my @mirrors        = $mirrors->get_mirrors_by_continents( $best_continent );

           my $callback = sub {
               my( $m ) = @_;
               printf "%s = %s\n", $m->hostname, $m->rtt
               };
           $mirrors->get_mirrors_timings( \@mirrors, $seen, $callback, %args );

           @mirrors = sort { $a->rtt <=> $b->rtt } @mirrors;

           print "Best mirrors are ", map( { $_->rtt } @mirrors[0..3] ), "\n";

DESCRIPTION

       new( LOCAL_FILE_NAME )
           Create a new CPAN::Mirrors object from LOCAL_FILE_NAME. This file should look like
           that in http://www.cpan.org/MIRRORED.BY .

       continents()
           Return a list of continents based on those defined in MIRRORED.BY.

       countries( [CONTINENTS] )
           Return a list of countries based on those defined in MIRRORED.BY.  It only returns
           countries for the continents you specify (as defined in "continents"). If you don't
           specify any continents, it returns all of the countries listed in MIRRORED.BY.

       mirrors( [COUNTRIES] )
           Return a list of mirrors based on those defined in MIRRORED.BY.  It only returns
           mirrors for the countries you specify (as defined in "countries"). If you don't
           specify any countries, it returns all of the mirrors listed in MIRRORED.BY.

       get_mirrors_by_countries( [COUNTRIES] )
           A more sensible synonym for mirrors.

       get_mirrors_by_continents( [CONTINENTS] )
           Return a list of mirrors for all of continents you specify. If you don't specify any
           continents, it returns all of the mirrors.

           You can specify a single continent or an array reference of continents.

       get_countries_by_continents( [CONTINENTS] )
           A more sensible synonym for countries.

       default_mirror
           Returns the default mirror, http://www.cpan.org/ . This mirror uses dynamic DNS to
           give a close mirror.

       best_mirrors
           "best_mirrors" checks for the best mirrors based on the list of continents you pass,
           or, without that, all continents, as defined by "CPAN::Mirrored::By". It pings each
           mirror, up to the value of "how_many". In list context, it returns up to "how_many"
           mirrors.  In scalar context, it returns the single best mirror.

           Arguments

               how_many      - the number of mirrors to return. Default: 1
               callback      - a callback for find_best_continents
               verbose       - true or false on all the whining and moaning. Default: false
               continents    - an array ref of the continents to check
               external_ping - if true, use external ping via Net::Ping::External. Default: false

           If you don't specify the continents, "best_mirrors" calls "find_best_continents" to
           get the list of continents to check.

           If you don't have Net::Ping v2.13 or later, needed for timings, this returns the
           default mirror.

           "external_ping" should be set and then "Net::Ping::External" needs to be installed, if
           the local network has a transparent proxy.

       get_n_random_mirrors_by_continents( N, [CONTINENTS] )
           Returns up to N random mirrors for the specified continents. Specify the continents as
           an array reference.

       get_mirrors_timings( MIRROR_LIST, SEEN, CALLBACK, %ARGS );
           Pings the listed mirrors and returns a list of mirrors sorted in ascending ping times.

           "MIRROR_LIST" is an anonymous array of "CPAN::Mirrored::By" objects to ping.

           The optional argument "SEEN" is a hash reference used to track the mirrors you've
           already pinged.

           The optional argument "CALLBACK" is a subroutine reference to call after each ping. It
           gets the "CPAN::Mirrored::By" object after each ping.

       find_best_continents( HASH_REF );
           "find_best_continents" goes through each continent and pings "N" random mirrors on
           that continent. It then orders the continents by ascending median ping time. In list
           context, it returns the ordered list of continent. In scalar context, it returns the
           same list as an anonymous array.

           Arguments:

               n        - the number of hosts to ping for each continent. Default: 3
               seen     - a hashref of cached hostname ping times
               verbose  - true or false for noisy or quiet. Default: false
               callback - a subroutine to run after each ping.
               ping_cache_limit - how long, in seconds, to reuse previous ping times.
                   Default: 1 day

           The "seen" hash has hostnames as keys and anonymous arrays as values.  The anonymous
           array is a triplet of a "CPAN::Mirrored::By" object, a ping time, and the epoch time
           for the measurement.

           The callback subroutine gets the "CPAN::Mirrored::By" object, the ping time, and
           measurement time (the same things in the "seen" hashref) as arguments.
           "find_best_continents" doesn't care what the callback does and ignores the return
           value.

           With a low value for "N", a single mirror might skew the results enough to choose a
           worse continent. If you have that problem, try a larger value.

AUTHOR

       Andreas Koenig "<andk@cpan.org>", David Golden "<dagolden@cpan.org>", brian d foy
       "<bdfoy@cpan.org>"

LICENSE

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

       See <http://www.perl.com/perl/misc/Artistic.html>