Google Hacks 2Nd Edition [Electronic resources]

Hack 94. Program Google with the Net::Google Perl Module

A crisp, clean, object-oriented alternative to programming Google with Perl and the SOAP::Lite module .

An alternative, more object-oriented Perl interface to the Google API is Aaron Straup Cope's Net::Google

(http://search.cpan.org/search?query=net+ google&mode=module). While not fundamentally different from using SOAP::Lite [Hack #93] as we do throughout this book, constructing Google API queries and dealing with the results is a little cleaner.

There are three main Google API interfaces defined by the module: search(), spelling(), and cache( ) for talking to the Google Web search engine, spellchecker, and Google cache, respectively.

To provide a side-by-side comparison to googly.pl [Hack #92] , the typical SOAP::Lite -based way to talk to the Google API, we've provided a script identical in function and almost so in structure.

9.11.1. The Code

Save the following script as net_googly.pl. Replace insert key here with your Google API key as you type in the code.

#!/usr/local/bin/perl # net_googly.pl # A typical Google API script using the Net::Google Perl module. # Usage: perl net_googly.pl <query> use strict; # Use the Net::Google Perl module.

use Net::Google; # Your Google API developer's key. use constant GOOGLE_API_KEY => 'insert key here'; # Take the query from the command line. my $query = shift @ARGV or die "Usage: perl net_googly.pl <query>\n";

# Create a new Net::Google instance .

my $google = Net::Google->new(key => GOOGLE_API_KEY);

# And create a new Net::Google search instance .

my $search = $google->search( );

# Build a Google query .

$search->query($query);

$search->starts_at(0);

$search->max_results(10);

$search->filter(0); # Query Google.

$search->results( ); # Loop through the results. foreach my $result ( @{ $search->results( ) } ) { # Print out the main bits of each result. print join "\n", $result->title( ) || "no title", $result->URL( ), $result->snippet( ) || 'no snippet', "\n"; } Notice that the code is all but identical to that of googly.pl [Hack #92] . The only real changes (called out in bold) are cleaner object-oriented method calls for setting query parameters and dealing with the results. So, rather than passing a set of parameters to a SOAP::Lite service call like this:

doGoogleSearch( $google_key, $query, 0, 10, "false", ", "false", ", "latin1", "latin1" );

Set these parameters individually like this:

$search->query($query); $search->starts_at(0); $search->max_results(10); $search->filter(0);

Not much difference, but definitely cleaner.

9.11.2. Running the Hack

Invoke the hack on the command line in just the same manner you did in [Hack #92] :

$ perl net_googly.pl " query keywords " The results will be just the same.