summaryrefslogtreecommitdiff
path: root/Master/tlpkg/TeXLive/TLDownload.pm
blob: 75fd01fa18bd6f944499f31a99a168ebe164e0e7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
# $Id$
# 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: #