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

I'm sure I must be being completely dense somehow, but I can't get JSON::RPC::Client to work as per the documentation on CPAN. 
#!/usr/bin/perl

use JSON::RPC::Client;
use Data::Dumper;

my $client = new JSON::RPC::Client;
my $url = 'http://9999.9999.9999.9999/api_jsonrpc.php';

my $callobj = {
        method => 'user.authenticate',
        params => ["admin","password"] };

print Dumper(ref($callobj));

my $sessionid = $client->call($url, $callobj);

if($sessionid) {
        if ($sessionid->is_error) {
        print "Error : ", $sessionid->error_message;
        } else {
                print $sessionid->result;
        }
} else {
        print $client->status_line;
}

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IP, username and password have been substituted for generic ones. I'm trying to connect to the Zabbix API running on a test server. A test PHP script works fine. JSON::RPC::Client sits and complains that I'm not passing it a hash. Running it I get: 
$VAR1 = 'HASH';
Not a HASH reference at /usr/local/share/perl/5.10.0/JSON/RPC/Client.p
+m line 194.

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so I presumably know for sure that $callobj is a hash? I've also tried putting params in the format: params => { username=>"admin", password=>"password" } Again this was to no avail, same error message. line 194 relates to JSON::RPC::Client's returning section, "new" subroutine (194 line starts $content->{error} ): 
sub new {
    my ($class, $obj, $json) = @_;
    my $content = ( $json || JSON->new->utf8 )->decode( $obj->content 
+);

    my $self = bless {
        jsontext  => $obj->content,
        content   => $content,
    }, $class;

    $content->{error} ? $self->is_success(0) : $self->is_success(1);

    $content->{version} ? $self->version(1.1) : $self->version(0) ;

    $self;
}

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Help me please perl monks, I'm utterly flummoxed.

Replies are listed 'Best First'.
Re: Grappling with JSON::RPC::Client
by gmargo (Hermit) on Jan 06, 2010 at 00:20 UTC

    I modified your code only to remove "use RPC::Lite::Client;" and add "use JSON::RPC::Client;" (and add strictures).

    I did not see the error you did using the latest JSON-2.16 and JSON-RPC-0.96. It got as far as: 

    $VAR1 = 'HASH';
500 Can't connect to 9999.9999.9999.9999:80 (Bad hostname '9999.9999.9
+999.9999')

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    so it certainly got past the constructor.

[reply]
[d/l]
[select]
      That was a hangover from a previous experiment with other Perl modules. Unsurprisingly 999.999.999.999 isn't a valid IP address, and the way JSON::RPC::Client appears to work is it checks the URI and goes on from there. When connecting to the valid IP it still gives me that hash error :-/
[reply]

        Sorry for the late reply here.

        Did a tcpdump on Zabbix 1.8 with this, and the result seems to indicate Zabbix uses JSON RPC 2.0 only: 

        [{"jsonrpc":"2.0","error":{"code":-32600,"message":"Invalid Request.",
+"data":"JSON-rpc version is not specified."},"id":null},{"jsonrpc":"2
+.0","error":{"code":-32600,"message":"Inval
id Request.","data":"Expacting JSON-rpc version 2.0, 1 is given ."},"i
+d":"1"},{"jsonrpc":"2.0","error":{"code":-32600,"message":"Invalid Re
+quest.","data":"Expacting JSON-rpc version 2.0, u is given ."},"id":"
+u"}

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[reply]
[d/l]

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