[27183] | 1 | package LWP::ConnCache;
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| 2 |
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| 3 | use strict;
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| 4 | use vars qw($VERSION $DEBUG);
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| 5 |
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| 6 | $VERSION = "5.810";
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| 7 |
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| 8 |
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| 9 | sub new {
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| 10 | my($class, %cnf) = @_;
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| 11 | my $total_capacity = delete $cnf{total_capacity};
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| 12 | $total_capacity = 1 unless defined $total_capacity;
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| 13 | if (%cnf && $^W) {
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| 14 | require Carp;
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| 15 | Carp::carp("Unrecognised options: @{[sort keys %cnf]}")
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| 16 | }
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| 17 | my $self = bless { cc_conns => [] }, $class;
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| 18 | $self->total_capacity($total_capacity);
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| 19 | $self;
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| 20 | }
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| 21 |
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| 22 |
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| 23 | sub deposit {
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| 24 | my($self, $type, $key, $conn) = @_;
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| 25 | push(@{$self->{cc_conns}}, [$conn, $type, $key, time]);
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| 26 | $self->enforce_limits($type);
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| 27 | return;
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| 28 | }
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| 29 |
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| 30 |
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| 31 | sub withdraw {
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| 32 | my($self, $type, $key) = @_;
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| 33 | my $conns = $self->{cc_conns};
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| 34 | for my $i (0 .. @$conns - 1) {
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| 35 | my $c = $conns->[$i];
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| 36 | next unless $c->[1] eq $type && $c->[2] eq $key;
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| 37 | splice(@$conns, $i, 1); # remove it
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| 38 | return $c->[0];
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| 39 | }
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| 40 | return undef;
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| 41 | }
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| 42 |
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| 43 |
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| 44 | sub total_capacity {
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| 45 | my $self = shift;
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| 46 | my $old = $self->{cc_limit_total};
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| 47 | if (@_) {
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| 48 | $self->{cc_limit_total} = shift;
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| 49 | $self->enforce_limits;
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| 50 | }
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| 51 | $old;
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| 52 | }
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| 53 |
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| 54 |
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| 55 | sub capacity {
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| 56 | my $self = shift;
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| 57 | my $type = shift;
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| 58 | my $old = $self->{cc_limit}{$type};
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| 59 | if (@_) {
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| 60 | $self->{cc_limit}{$type} = shift;
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| 61 | $self->enforce_limits($type);
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| 62 | }
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| 63 | $old;
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| 64 | }
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| 65 |
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| 66 |
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| 67 | sub enforce_limits {
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| 68 | my($self, $type) = @_;
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| 69 | my $conns = $self->{cc_conns};
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| 70 |
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| 71 | my @types = $type ? ($type) : ($self->get_types);
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| 72 | for $type (@types) {
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| 73 | next unless $self->{cc_limit};
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| 74 | my $limit = $self->{cc_limit}{$type};
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| 75 | next unless defined $limit;
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| 76 | for my $i (reverse 0 .. @$conns - 1) {
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| 77 | next unless $conns->[$i][1] eq $type;
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| 78 | if (--$limit < 0) {
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| 79 | $self->dropping(splice(@$conns, $i, 1), "$type capacity exceeded");
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| 80 | }
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| 81 | }
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| 82 | }
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| 83 |
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| 84 | if (defined(my $total = $self->{cc_limit_total})) {
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| 85 | while (@$conns > $total) {
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| 86 | $self->dropping(shift(@$conns), "Total capacity exceeded");
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| 87 | }
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| 88 | }
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| 89 | }
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| 90 |
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| 91 |
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| 92 | sub dropping {
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| 93 | my($self, $c, $reason) = @_;
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| 94 | print "DROPPING @$c [$reason]\n" if $DEBUG;
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| 95 | }
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| 96 |
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| 97 |
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| 98 | sub drop {
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| 99 | my($self, $checker, $reason) = @_;
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| 100 | if (ref($checker) ne "CODE") {
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| 101 | # make it so
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| 102 | if (!defined $checker) {
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| 103 | $checker = sub { 1 }; # drop all of them
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| 104 | }
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| 105 | elsif (_looks_like_number($checker)) {
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| 106 | my $age_limit = $checker;
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| 107 | my $time_limit = time - $age_limit;
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| 108 | $reason ||= "older than $age_limit";
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| 109 | $checker = sub { $_[3] < $time_limit };
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| 110 | }
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| 111 | else {
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| 112 | my $type = $checker;
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| 113 | $reason ||= "drop $type";
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| 114 | $checker = sub { $_[1] eq $type }; # match on type
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| 115 | }
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| 116 | }
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| 117 | $reason ||= "drop";
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| 118 |
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| 119 | local $SIG{__DIE__}; # don't interfere with eval below
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| 120 | local $@;
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| 121 | my @c;
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| 122 | for (@{$self->{cc_conns}}) {
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| 123 | my $drop;
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| 124 | eval {
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| 125 | if (&$checker(@$_)) {
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| 126 | $self->dropping($_, $reason);
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| 127 | $drop++;
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| 128 | }
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| 129 | };
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| 130 | push(@c, $_) unless $drop;
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| 131 | }
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| 132 | @{$self->{cc_conns}} = @c;
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| 133 | }
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| 134 |
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| 135 |
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| 136 | sub prune {
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| 137 | my $self = shift;
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| 138 | $self->drop(sub { !shift->ping }, "ping");
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| 139 | }
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| 140 |
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| 141 |
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| 142 | sub get_types {
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| 143 | my $self = shift;
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| 144 | my %t;
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| 145 | $t{$_->[1]}++ for @{$self->{cc_conns}};
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| 146 | return keys %t;
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| 147 | }
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| 148 |
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| 149 |
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| 150 | sub get_connections {
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| 151 | my($self, $type) = @_;
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| 152 | my @c;
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| 153 | for (@{$self->{cc_conns}}) {
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| 154 | push(@c, $_->[0]) if !$type || ($type && $type eq $_->[1]);
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| 155 | }
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| 156 | @c;
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| 157 | }
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| 158 |
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| 159 |
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| 160 | sub _looks_like_number {
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| 161 | $_[0] =~ /^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/;
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| 162 | }
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| 163 |
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| 164 | 1;
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| 165 |
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| 166 |
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| 167 | __END__
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| 168 |
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| 169 | =head1 NAME
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| 170 |
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| 171 | LWP::ConnCache - Connection cache manager
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| 172 |
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| 173 | =head1 NOTE
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| 174 |
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| 175 | This module is experimental. Details of its interface is likely to
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| 176 | change in the future.
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| 177 |
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| 178 | =head1 SYNOPSIS
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| 179 |
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| 180 | use LWP::ConnCache;
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| 181 | my $cache = LWP::ConnCache->new;
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| 182 | $cache->deposit($type, $key, $sock);
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| 183 | $sock = $cache->withdraw($type, $key);
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| 184 |
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| 185 | =head1 DESCRIPTION
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| 186 |
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| 187 | The C<LWP::ConnCache> class is the standard connection cache manager
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| 188 | for LWP::UserAgent.
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| 189 |
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| 190 | The following basic methods are provided:
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| 191 |
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| 192 | =over
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| 193 |
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| 194 | =item $cache = LWP::ConnCache->new( %options )
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| 195 |
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| 196 | This method constructs a new C<LWP::ConnCache> object. The only
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| 197 | option currently accepted is 'total_capacity'. If specified it
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| 198 | initialize the total_capacity option. It defaults to the value 1.
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| 199 |
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| 200 | =item $cache->total_capacity( [$num_connections] )
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| 201 |
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| 202 | Get/sets the number of connection that will be cached. Connections
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| 203 | will start to be dropped when this limit is reached. If set to C<0>,
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| 204 | then all connections are immediately dropped. If set to C<undef>,
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| 205 | then there is no limit.
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| 206 |
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| 207 | =item $cache->capacity($type, [$num_connections] )
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| 208 |
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| 209 | Get/set a limit for the number of connections of the specified type
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| 210 | that can be cached. The $type will typically be a short string like
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| 211 | "http" or "ftp".
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| 212 |
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| 213 | =item $cache->drop( [$checker, [$reason]] )
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| 214 |
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| 215 | Drop connections by some criteria. The $checker argument is a
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| 216 | subroutine that is called for each connection. If the routine returns
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| 217 | a TRUE value then the connection is dropped. The routine is called
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| 218 | with ($conn, $type, $key, $deposit_time) as arguments.
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| 219 |
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| 220 | Shortcuts: If the $checker argument is absent (or C<undef>) all cached
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| 221 | connections are dropped. If the $checker is a number then all
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| 222 | connections untouched that the given number of seconds or more are
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| 223 | dropped. If $checker is a string then all connections of the given
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| 224 | type are dropped.
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| 225 |
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| 226 | The $reason argument is passed on to the dropped() method.
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| 227 |
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| 228 | =item $cache->prune
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| 229 |
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| 230 | Calling this method will drop all connections that are dead. This is
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| 231 | tested by calling the ping() method on the connections. If the ping()
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| 232 | method exists and returns a FALSE value, then the connection is
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| 233 | dropped.
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| 234 |
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| 235 | =item $cache->get_types
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| 236 |
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| 237 | This returns all the 'type' fields used for the currently cached
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| 238 | connections.
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| 239 |
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| 240 | =item $cache->get_connections( [$type] )
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| 241 |
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| 242 | This returns all connection objects of the specified type. If no type
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| 243 | is specified then all connections are returned. In scalar context the
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| 244 | number of cached connections of the specified type is returned.
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| 245 |
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| 246 | =back
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| 247 |
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| 248 |
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| 249 | The following methods are called by low-level protocol modules to
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| 250 | try to save away connections and to get them back.
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| 251 |
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| 252 | =over
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| 253 |
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| 254 | =item $cache->deposit($type, $key, $conn)
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| 255 |
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| 256 | This method adds a new connection to the cache. As a result other
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| 257 | already cached connections might be dropped. Multiple connections with
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| 258 | the same $type/$key might added.
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| 259 |
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| 260 | =item $conn = $cache->withdraw($type, $key)
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| 261 |
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| 262 | This method tries to fetch back a connection that was previously
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| 263 | deposited. If no cached connection with the specified $type/$key is
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| 264 | found, then C<undef> is returned. There is not guarantee that a
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| 265 | deposited connection can be withdrawn, as the cache manger is free to
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| 266 | drop connections at any time.
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| 267 |
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| 268 | =back
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| 269 |
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| 270 | The following methods are called internally. Subclasses might want to
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| 271 | override them.
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| 272 |
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| 273 | =over
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| 274 |
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| 275 | =item $conn->enforce_limits([$type])
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| 276 |
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| 277 | This method is called with after a new connection is added (deposited)
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| 278 | in the cache or capacity limits are adjusted. The default
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| 279 | implementation drops connections until the specified capacity limits
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| 280 | are not exceeded.
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| 281 |
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| 282 | =item $conn->dropping($conn_record, $reason)
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| 283 |
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| 284 | This method is called when a connection is dropped. The record
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| 285 | belonging to the dropped connection is passed as the first argument
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| 286 | and a string describing the reason for the drop is passed as the
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| 287 | second argument. The default implementation makes some noise if the
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| 288 | $LWP::ConnCache::DEBUG variable is set and nothing more.
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| 289 |
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| 290 | =back
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| 291 |
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| 292 | =head1 SUBCLASSING
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| 293 |
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| 294 | For specialized cache policy it makes sense to subclass
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| 295 | C<LWP::ConnCache> and perhaps override the deposit(), enforce_limits()
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| 296 | and dropping() methods.
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| 297 |
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| 298 | The object itself is a hash. Keys prefixed with C<cc_> are reserved
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| 299 | for the base class.
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| 300 |
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| 301 | =head1 SEE ALSO
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| 302 |
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| 303 | L<LWP::UserAgent>
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| 304 |
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| 305 | =head1 COPYRIGHT
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| 306 |
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| 307 | Copyright 2001 Gisle Aas.
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| 308 |
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| 309 | This library is free software; you can redistribute it and/or
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| 310 | modify it under the same terms as Perl itself.
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