Google Hacks 2Nd Edition [Electronic resources] نسخه متنی

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.

Mind you, you'll still need SOAP::Lite and a couple of other prerequisites to use Net::Google .

#!/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.