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.

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