Hack 32. Dig Deeper into Sites

Dig deeper into the hierarchies of web sites matching your search criteria.

One of Google's big strengths is that it can find your search term instantly and with great precision. But sometimes you're not interested so much in one definitive result as in lots of diverse results; maybe you even want some that are a bit more on the obscure side.

One method I've found rather useful is to ignore all results shallower than a particular level in a site's directory hierarchy. You avoid all the clutter of finds on home pages and go for subject matter otherwise hidden away in the depths of a site's structure. While content comes and goes, ebbs and flows from a site's main focus, it tends to gather in more permanent locales, categorized and archived, like with like.

This script asks for a query along with a preferred depth, above which results are thrown out. Specify a depth of four and your results will come only from http://example.com/a/b/c/d, not /a, /a/b/, or /a/b/c.

Because you're already limiting the kinds of results that you see, it's best to use more common words for what you're looking for. Obscure query terms can often return absolutely no results.

The default number of loops, retrieving 10 items apiece, is set to 50. This is to assure that you glean some decent number of results because many will be tossed. You can, of course, alter this number, but bear in mind that you're using that number of your daily quota of 1,000 Google API queries per developer's key.

2.14.1. The Code

Save this code as deep_blue_g.cgi, a CGI script ["How to Run the Hacks" in the Preface] on your web server. As you type it in, replace insert key here with your Google API key.

#!/usr/local/bin/perl

# deep_blue_g.cgi

# Limiting search results to a particular depth in a web 

# site's hierarchy.

# deep_blue_g.cgi is called as a CGI with form input.

     

# Your Google API developer's key.

my $google_key='insert key here';

     

# Location of the GoogleSearch WSDL file.

my $google_wdsl = "./GoogleSearch.wsdl";

     

# Number of times to loop, retrieving 10 results at a time.

my $loops = 10;

     

use SOAP::Lite;

use CGI qw/:standard *table/;

     

print

  header( ),

  start_html("Fishing in the Deep Blue G"),

  h1("Fishing in the Deep Blue G"),

  start_form(-method=>'GET'),

  'Query: ', textfield(-name=>'query'),

  br( ),

  'Depth: ', textfield(-name=>'depth', -default=>4),

  br( ),

  submit(-name=>'submit', -value=>'Search'),

  end_form( ), p( );

     

# Make sure a query and numeric depth are provided.

if (param('query') and param('depth') =~ /\d+/) {

     

  # Create a new SOAP object.

  my $google_search  = SOAP::Lite->service("file:$google_wdsl");

     

  for (my $offset = 0; $offset <= $loops*10; $offset += 10) {

    my $results = $google_search -> 

      doGoogleSearch(

        $google_key, param('query'), $offset, 10, "false", "",  "false",

        "", "latin1", "latin1"

      );

     

    last unless @{$results->{resultElements}};

     

    foreach my $result (@{$results->{'resultElements'}}) {

     

      # Determine depth.

      my $url = $result->{URL};

      $url =~ s!^\w+://|/$!!g;

     

      # Output only those deep enough.

      ( split(/\//, $url) - 1) >= param('depth') and 

        print 

          p(

            b(a({href=>$result->{URL}},$result->{title}||'no title')), br( ),

            $result->{URL}, br( ),

            i($result->{snippet}||'no snippet')

          );

    }

  }

     

  print end_html;

}

2.14.2. Running the Hack

This hack runs as a CGI script. Point your browser at deep_blue_g.cgi, fill out the query and depth fields, and click the Submit button.

Figure 2-8 shows a query for "Jacques Cousteau", restricting results to a depth of six; that's six levels down from the site's home page. You'll notice some pretty long URLs in there.

Figure 2-8. A search for "Jacques Cousteau", restricting results to six levels down

2.14.3. Hacking the Hack

Perhaps you're interested in just the opposite of what this hack provides: you want only results from higher up in a site's hierarchy. Hacking this hack is simple enough: swap in a < (less than) symbol instead of the > (greater than) in the following line:

      ( split(/\//, $url) - 1) <= param('depth') and

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