three18ti has asked for the wisdom of the Perl Monks concerning the following question:

HEllo Monks

Back at it again. Trying to figure out how to use a handler. I'm following the example Re^5: SOAP::Lite method with one param. When I add the "request_send" handler I receive an error. If I change the name of the handler to "request_done" or "request_prepare" I don't receive an error.

The error:

Can't locate object method "request" via package "1" (perhaps you forg
+ot to load "1"?) at /usr/local/share/perl/5.18.2/LWP/UserAgent.pm lin
+e 216.

[download]

Actually, this appears to be an issue with LWP::UserAgent

#!/usr/bin/env perl

use strict;
use warnings;

use LWP::UserAgent;
use Data::Dumper;

my $ua = LWP::UserAgent->new;

$ua->add_handler('request_send', \&pp_dump);

$ua->post("http://google.com");

sub pp_dump {
    print Dumper @_;
}

[download]

This is the SOAP code I was working with

#!/usr/bin/env perl
use strict;
use warnings;

use 5.010;

use SOAP::Lite;
SOAP::Lite->import(+trace => 'all');

use Data::Dumper;

my $client = SOAP::Lite->proxy($proxy)
    ->ns($namespace, 'foo')
    ->uri($uri)
    ->on_action(sub { sprintf '%s', $_[0] })
    ->on_fault(sub {
       my($soap, $result) = @_;
       die ref $result ?
        "Fault Code: " . $result->faultcode . "\n" 
            .  "Fault String: " . $result->faultstring . "\n"
        : $soap->transport->status, "\n";
     });

my $params = { foo => 'bar', biz => 'baz'};

# does not cause error
# $client->transport->add_handler("request_prepare", \&pp_dump );

# causes error
$client->transport->add_handler("request_send", \&pp_dump );

my $result = $client->call('my_api_method' => $params);

sub pp_dump {
    print Dumper @_;
}

[download]

Thanks!

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Re: [LWP::UserAgent] 'Can't locate object method "request" via package "1" when attempting to add a hander
by Anonymous Monk on Jan 30, 2015 at 00:47 UTC

    Back at it again. ... just guessing

    You're not very good at guessing, I suggest you study the docs some more 

    $ perl studythedocs.pl
** POST http://example.com ==> 200 OK (3s)

$ perl studythedocs.pl add_handler
** POST http://example.com ==> $VAR1 = bless( {
...**snip**...
$VAR3 = $VAR2->{'handlers'}{'request_send'}[0];
Can't call method "request" without a package or object reference at C
+:/citrusperl/site/lib/LWP/UserAgent.pm line 216.

    [download]
[reply]
[d/l]

      Thinking about it, it actually makes sense to modify the header in the "request_prepare" phase. Since, while I'm modifying the header I'm still in the "prepare" phase.

      So other than using "request_prepare" to solve my problem, I think there is rationale behind using it over "request_send"

      According to the lwp documentation, the signature of @_ is the same, header, useragent, and the handler. "sub { my($request, $ua, $h) = @_; ... }"

      I'm not sure what you're trying to show me. You get the same error I do. Why does dumping a variable cause it to cause an error? In calling "print Dumper @_" where am I calling request?

      Add to that I change handlers without changing code and dumping @_ doesn't generate an error. According to the LWP docs the @_ has the same signature.

[reply]

        ...

        request_send => sub { my($request, $ua, $h) = @_; ... }

        This handler gets a chance of handling requests before they're sent to the protocol handlers. It should return an HTTP::Response object if it wishes to terminate the processing; otherwise it should return nothing.

        The response_header and response_data handlers will not be invoked for this response, but the response_done will be.

[reply]

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