How to print out JSON object in perl using AnyEvent::Twitter::Stream - perl

Question

I'm using the AnyEvent::Twitter::Stream module to grab tweets. Ultimately I'm trying to print the tweets to a file but I'm unable (I think) to get the tweet as a JSON object. My code is as follows:
#!/Applications/XAMPP/xamppfiles/bin/perl
use AnyEvent::Twitter::Stream;
my $done = AnyEvent->condvar;
BEGIN {
use Exporter;
our #ISA = qw(Exporter);
our #EXPORT = qw{
&init
};
}
sub print_tweet {
my $tweet = shift;
print $tweet;
}
# receive updates from #following_ids
my $listener = AnyEvent::Twitter::Stream->new(
username => XXXXXX
password => XXXXXX
method => 'sample', # "firehose" for everything, "sample" for sample timeline
decode_json => 1,
on_tweet => sub {
my $tweet = shift;
print_tweet($tweet);
},
on_keepalive => sub {
warn "ping\n";
},
on_delete => sub {
my ($tweet_id, $user_id) = #_; # callback executed when twitter send a delete notification
},
timeout => 45,
);
$done->recv;
Yet when I print out the tweet in the print_tweet subroutine all I get is:
HASH(0x8f0ad0)HASH(0x8f0640)HASH(0x875990)HASH(0x8f0ab0)HASH(0x8e0d80)HASH(0x8f06e0)HASH(0x8f08f0)HASH(0x93ef30)HASH(0x876190)HASH(0x93ee60)HASH(0x8f0610)HASH(0x8f0b00)HASH(0x8e13e0)HASH(0x93ee20)HASH(0x8f0a20)HASH(0x8e1970)HASH(0x8f0900)
I've even tried to print out the tweet assuming it is a hash as follows:
sub print_tweet {
my ($jsonref, $tweet) = #_;
my $tweet = shift;
print %tweet;
}
Yet that produced nothing. It appears that AnyEvent::Twitter::Stream is returning $tweet as an object based on their sample code of:
on_tweet => sub {
my $tweet = shift;
warn "$tweet->{user}{screen_name}: $tweet->{text}\n";
},
And I know I can print out individual objects, but can I get teh raw JSON object? I must be missing something or my 'noob'ness is greater than I thought...
UPDATE
I was able to ALMOST get it by changing print_tweet to the following:
sub print_tweet {
my $tweet = shift;
my $json_output = to_json($tweet);
print $json_output;
}
It prints out MOST of the JSON object but complains about wide characters, which I believe is an issue with the output being utf8 format? I'm unsure how to solve this issue though....

Answer 1

Looks like it's returning a hashref. If you're not sure, you could try doing something like this.
use Data::Dumper;
...
print Dumper $tweet;
That should give you an idea of what's being passed, then you can grab what you want - probably something like this:
print "$tweet->{user}{screen_name}: $tweet->{text}\n";

Answer 2

In print_tweet, you're declaring $tweet twice. First, you assign it the second element of the #_ array, then you redeclare it and assign it the first element of #_, because shift operated on #_ by default.
Of course, if you had use warnings turned on, you would have seen
"my" variable $tweet masks earlier declaration in same scope
That's why you should always use strict; use warnings; at the top of your code.
The strings of output that you're seeing are hash references, the result of printing what's in the first argument to print_tweet (what you initially assign to $json_ref). If you want to print out the value of $tweet, get rid of the line where you clobber it with shift.

Answer 3

Figured it out. Need to use the JSON module and encode. When encoding you MUST use the {utf8 => 1} option to account for the utf8 characters you get form Twitter. Final code is here:
#!/Applications/XAMPP/xamppfiles/bin/perl
use JSON;
use utf8;
use AnyEvent::Twitter::Stream;
my $done = AnyEvent->condvar;
BEGIN {
use Exporter;
our #ISA = qw(Exporter);
our #EXPORT = qw{
&init
};
}
sub print_tweet {
my $tweet = shift;
my $json_output = to_json($tweet, {utf8 => 1});
print $json_output;
print "\n";
}
# receive updates from #following_ids
my $listener = AnyEvent::Twitter::Stream->new(
username => XXXXXXXX
password => XXXXXXXX
method => 'sample', # "firehose" for everything, "sample" for sample timeline
on_tweet => sub {
my $tweet = shift;
print_tweet($tweet);
},
on_keepalive => sub {
warn "ping\n";
},
on_delete => sub {
my ($tweet_id, $user_id) = #_; # callback executed when twitter send a delete notification
},
timeout => 45,
);
$done->recv;
Thanks to the help you guys gave, the DataDumper at least let me verify the format, it just didn't produce the final result.