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

( #5352=categorized question: print w/ replies, xml ) Need Help??
Contributed by capa on Mar 14, 2000 at 15:57 UTC
Q&A  > HTTP and FTP clients


Description:

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.

Answer: LWP::Simple, a bug in head() function?
contributed by ender

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; }

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]:~/

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?

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