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# $Id$
# TeXLive::TLDownload.pm - module for abstracting the download modes
# Copyright 2009-2021 Norbert Preining
# This file is licensed under the GNU General Public License version 2
# or any later version.
use strict; use warnings;
package TeXLive::TLDownload;
use TeXLive::TLUtils;
use TeXLive::TLConfig;
my $svnrev = '$Revision$';
my $_modulerevision;
if ($svnrev =~ m/: ([0-9]+) /) {
$_modulerevision = $1;
} else {
$_modulerevision = "unknown";
}
sub module_revision {
return $_modulerevision;
}
# since Net::HTTP and Net::FTP are shipped by the same packages
# we only test for Net::HTTP, if that fails, let us know ;-)
our $net_lib_avail = 0;
eval { require LWP; };
if ($@) {
debug("LWP is not available, falling back to wget.\n");
$net_lib_avail = 0;
} else {
require LWP::UserAgent;
require HTTP::Status;
$net_lib_avail = 1;
ddebug("LWP available, doing persistent downloads.\n");
}
sub new
{
my $class = shift;
my $self = {};
$self->{'initcount'} = 0;
bless $self, $class;
$self->reinit();
return $self;
}
sub reinit {
my $self = shift;
# Irritatingly, as of around version 6.52, when env_proxy is set, LWP
# started unconditionally complaining if the environment contains
# differing case-insensitive like foo=1 and FOO=2. Even on systems
# that have case-sensitive environments, and even about variables that
# have nothing whatsoever to do with LWP (like foo).
#
# So, only pass env_proxy=>1 when creating the UserAgent if there are
# in fact *_proxy variables (case-insensitive, just in case) set in
# the environment.
#
my @env_proxy = ();
if (grep { /_proxy/i } keys %ENV ) {
@env_proxy = ("env_proxy", 1);
}
#
my $ua = LWP::UserAgent->new(
agent => "texlive/lwp",
# use LWP::ConnCache, and keep 1 connection open
keep_alive => 1,
timeout => $TeXLive::TLConfig::NetworkTimeout,
@env_proxy,
);
$self->{'ua'} = $ua;
$self->{'enabled'} = 1;
$self->{'errorcount'} = 0;
$self->{'initcount'} += 1;
}
sub enabled {
my $self = shift;
return $self->{'enabled'};
}
sub disabled
{
my $self = shift;
return (!$self->{'enabled'});
}
sub enable
{
my $self = shift;
$self->{'enabled'} = 1;
# also reset the error conter
$self->reset_errorcount;
}
sub disable
{
my $self = shift;
$self->{'enabled'} = 0;
}
sub initcount
{
my $self = shift;
return $self->{'initcount'};
}
sub errorcount
{
my $self = shift;
if (@_) { $self->{'errorcount'} = shift }
return $self->{'errorcount'};
}
sub incr_errorcount
{
my $self = shift;
return(++$self->{'errorcount'});
}
sub decr_errorcount
{
my $self = shift;
if ($self->errorcount > 0) {
return(--$self->{'errorcount'});
} else {
return($self->errorcount(0));
}
}
sub reset_errorcount {
my $self = shift;
$self->{'errorcount'} = 0;
}
sub get_file {
my ($self,$url,$out,$size) = @_;
#
# automatically disable if error count is getting too big
if ($self->errorcount > $TeXLive::TLConfig::MaxLWPErrors) {
$self->disable;
}
# return if disabled
return if $self->disabled;
#
my $realout = $out;
my ($outfh, $outfn);
if ($out eq "|") {
($outfh, $outfn) = tl_tmpfile();
$realout = $outfn;
}
my $response = $self->{'ua'}->get($url, ':content_file' => $realout);
if ($response->is_success) {
$self->decr_errorcount;
if ($out ne "|") {
return 1;
} else {
# seek to beginning of file
seek $outfh, 0, 0;
return $outfh;
}
} else {
debug("TLDownload::get_file: response error: "
. $response->status_line . " (for $url)\n");
$self->incr_errorcount;
return;
}
}
1;
__END__
=head1 NAME
C<TeXLive::TLDownload> -- TeX Live persistent downloads via LWP
=head1 SYNOPSIS
use TeXLive::TLDownload;
$TeXLive::TLDownload::net_lib_avail
my $dl = TeXLive::TLDownload->new();
$dl->get_file($relpath, $output [, $expected_size ]);
if ($dl->enabled) ...
if ($dl->disabled) ...
$dl->enable;
$dl->disable;
$dl->errorcount([n]);
$dl->incr_errorcount;
$dl->decr_errorcount;
$dl->reset_errorcount;
=head1 DESCRIPTION
The C<TeXLive::TLDownload> is a wrapper around the LWP modules that
allows for persistent connections and different protocols. At load
time it checks for the existence of the LWP module(s), and sets
C<$TeXLive::TLDownload::net_lib_avail> accordingly.
=head2 Using proxies
Please see C<LWP::UserAgent> for details, in a nut shell one can
specify proxies by setting C<I<protocol>_proxy> variables.
=head2 Automatic disabling
The TLDownload module implements some automatic disabling feature.
Every time a download did not succeed an internal counter (errorcount)
is increased, everytime it did succeed it is decreased (to a minimum of 0).
If the number of error goes above the maximal error count, the download
object will be disabled and get_file always returns undef.
In this cases the download can be reset with the reset_errorcount and
enable function.
=head1 SEE ALSO
LWP
=head1 AUTHORS AND COPYRIGHT
This script and its documentation were written for the TeX Live
distribution (L<https://tug.org/texlive>) and both are licensed under the
GNU General Public License Version 2 or later.
=cut
### Local Variables:
### perl-indent-level: 2
### tab-width: 2
### indent-tabs-mode: nil
### End:
# vim:set tabstop=2 expandtab: #
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