Re: HTTP error response code 500 using LWP::UserAgent on one site, but not on any other

[Old_Gray_Bear]

in reply to HTTP error response code 500 using LWP::UserAgent on one site, but not on any other

An HTTP 500 error is a general error message issued by the server when no more specific 5xx message is appropriate. You will need to get the log(s) from the failing server to determine what exactly is going sour.

As a work around, you can have LWP send a user agent string identifying your 'browser' and one of the browsers that the remote server accepts. Note: this may lead to other "compatibility" issues.

[ted.byers]

Thanks OGB.

That is actually being done by the technical staff at the company that is providing the service. I have used such logs for my own web servers countless times to diagnose problems:usualy related to my own cgi programs, but sometimes to diagnose why my users encounter troubles.

That said, I doubt that he'd let me examine his logs, any more than I would let an outside developer examine my logs.

Do you have any thoughts on how to tell LWP to write the headers and request to a file instead of sending them to a server; or perhaps how to have it send to the logger suitable output for every step of the process of hand-shaking between the client and server, from the moment the connection is initiated to the moment the response is sent?

Thanks again.

Ted>

[Old_Gray_Bear]

They should be able to give you and extract of their logs if you provide them with a start and end time and the source host name/address. It's no big thing to filter a log for the time stamps in your range and then filter for your particular address. ISPs and their ilk have to do that to comply with a court-ordered "wiretap". (Or, how did they get the Generals email?)

[afoken]

An HTTP 500 error is a general error message issued by the server when no more specific 5xx message is appropriate.

Correct. But LWP may also generate 500 errors, as a way to communicate fatal errors to the caller:

#!/usr/bin/perl

use 5.010;
use strict;
use warnings;
use LWP::UserAgent;
use Data::Dumper;

my $ua=LWP::UserAgent->new();
my $resp=$ua->get("http://no.such.server.in.my.lan/no-such-page");

say $resp->status_line;
say Dumper $resp;

500 Can't connect to no.such.server.in.my.lan:80 (Bad hostname)
$VAR1 = bless( {
                 '_content' => 'Can\'t connect to no.such.server.in.my
+.lan:80 (Bad hostname)

LWP::Protocol::http::Socket: Bad hostname \'no.such.server.in.my.lan\'
+ at /usr/lib64/perl5/site_perl/5.12.3/LWP/Protocol/http.pm line 51.
',
                 '_rc' => 500,
                 '_headers' => bless( {
                                        'client-warning' => 'Internal 
+response',
                                        'client-date' => 'Sat, 17 Nov 
+2012 19:32:13 GMT',
                                        'content-type' => 'text/plain'
                                      }, 'HTTP::Headers' ),
                 '_msg' => 'Can\'t connect to no.such.server.in.my.lan
+:80 (Bad hostname)',
                 '_request' => bless( {
                                        '_content' => '',
                                        '_uri' => bless( do{\(my $o = 
+'http://no.such.server.in.my.lan/no-such-page')}, 'URI::http' ),
                                        '_headers' => bless( {
                                                               'user-a
+gent' => 'libwww-perl/6.02'
                                                             }, 'HTTP:
+:Headers' ),
                                        '_method' => 'GET'
                                      }, 'HTTP::Request' )
               }, 'HTTP::Response' );

Alexander