LWP::Simple, a bug in head() function?

capa has asked for the wisdom of the Perl Monks concerning the following question:

I need modified time for a web page, and i tried head() function from LWP::Simple interface. An example: i wrote the following test script

#!/usr/bin/perl
use LWP::Simple;
($content_type, $document_length, $modified_time, $expires, $server) = 
    head $ARGV[0];
print("$content_type <> ",
      "$document_length <> ",
      "$modified_time <> ",
      "$expires <> ",
      "$server\n");

and then i run it:

bash$ ./test_head.pl http://localhost/tmp
text/html <>  <> Apache/1.3.9 (Unix) Debian/GNU PHP/3.0.14 <>  <> 
bash$ ./test_head.pl http://localhost/   
text/html <> 274 <> 953031425 <> Apache/1.3.9 (Unix) Debian/GNU PHP/3.0.14 <>
bash$ ./test_head.pl http://localhost/index.html
text/html <> 274 <> 953031425 <> Apache/1.3.9 (Unix) Debian/GNU PHP/3.0.14 <>

As you can see server is not the last item of list returned by head, in fact it has no fixed position in that list. What's wrong? Thanks.

Originally posted as a Categorized Question.

Comment on LWP::Simple, a bug in head() function?

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Re: LWP::Simple, a bug in head() function? by ender (Novice) on Mar 24, 2000 at 00:32 UTC
Hrm, here's the code for the LWP::Simple::head() sub: `sub head ($) { my($url) = @_; _init_ua() unless $ua; my $request = HTTP::Request->new(HEAD => $url); my $response = $ua->request($request); if ($response->is_success) { return $response unless wantarray; return (scalar $response->header('Content-Type'), scalar $response->header('Content-Length'), HTTP::Date::str2time($response->header('Last-Modified' +)), HTTP::Date::str2time($response->header('Expires')), scalar $response->header('Server'), ); } return; }` [download] So it looks like it tries to return an array, but what happens if it doesn't get a modified time, or any other element for that matter? It seems to return whatever it gets w/o putting any placeholders in: `[jane]:~/cat test.pl #!/usr/bin/perl use strict; use LWP::Simple; my @array = head(shift); my $i = 0; foreach my $line (@array) { print "$i: $line\n"; $i++; } [jane]:~/perl test.pl http://www.fdntech.com 0: text/html 1: 2: Apache/1.3.11 (Unix) PHP/3.0.14 [jane]:~/` [download] So, it looks as though it's not really behaving how we would wish it to. Perhaps it should return a hash? Am I totally off-base there?	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re: LWP::Simple, a bug in head() function?
by ender (Novice) on Mar 24, 2000 at 00:32 UTC

sub head ($)
{
    my($url) = @_;
    _init_ua() unless $ua;

    my $request = HTTP::Request->new(HEAD => $url);
    my $response = $ua->request($request);

    if ($response->is_success) {
        return $response unless wantarray;
        return (scalar $response->header('Content-Type'),
                scalar $response->header('Content-Length'),
                HTTP::Date::str2time($response->header('Last-Modified'
+)),
                HTTP::Date::str2time($response->header('Expires')),
                scalar $response->header('Server'),
               );
    }
    return;
}
[download]

So it looks like it tries to return an array, but what happens if it doesn't get a modified time, or any other element for that matter? It seems to return whatever it gets w/o putting any placeholders in:

[jane]:~/cat test.pl 
#!/usr/bin/perl

use strict;
use LWP::Simple;
my @array = head(shift);
my $i = 0;
foreach my $line (@array) {
  print "$i: $line\n";
  $i++;
}

[jane]:~/perl test.pl http://www.fdntech.com
0: text/html
1: 
2: Apache/1.3.11 (Unix) PHP/3.0.14
[jane]:~/
[download]

So, it looks as though it's not really behaving how we would wish it to. Perhaps it should return a hash? Am I totally off-base there?

[reply]
[d/l]
[select]