NAME

Tie::Google - Single-variable access to Google search results

SYNOPSIS 

      my $KEYFILE = glob "~/.googlekey";
      my ($g, @g, %g);

      # Tied array interface
      tie @g, "Tie::Google", $KEYFILE, "perl";
      for my $r (@g) {
          printf " * <a href='%s'>%s</a>\n",
              $r->{'URL'}, $r->{'title'};
      }

      # Tied hash interface
      tie %g, "Tie::Google", $KEYFILE;
      for my $term (qw[ perl python ruby ]) {
          my $res = $g{$term};
          printf "%d results for '%s:\n", scalar @$res, $term;

          for my $r (@$res) {
              printf " * <a href='%s'>%s</a>\n",
                  $r->{'URL'}, $r->{'title'};
          }
      }

      # Tied scalar interface: I Feel Lucky
      use LWP::Simple qw(getprint);
      tie $g, "Tie::Google", $KEYFILE, "perl";
      getprint($g->{'URL'});

USING Tie::Google

Using tied variables can make searching Google much simpler for trivial programs. "Tie::Google" presents a simple interface to Google's search API, using "Net::Google" as the underlying transport mechanism. To use "Tie::Google", you must already be registered with Google and have an API key.

You can tie scalars, arrays, or hashes to the "Tie::Google" class; each offers slightly different functionality, but all offer direct access to Google search results. The basic syntax of all types is:

tie VAR, 'Tie::Google', $APIKEY, $QUERY, \%OPTIONS;

where

VAR VAR is the variable name, which can be a scalar, array, or hash: 

              tie $g, "Tie::Google", $KEY, $term;
              tie @g, "Tie::Google", $KEY, $term;
              tie %g, "Tie::Google", $KEY, $term;

$APIKEY APIKEY is your Google API key or a file containing the key as 

            the only item on the first line; see http://apis.google.com for
            details.

$QUERY QUERY is your actual search term(s), as a string. This can be

arbitrarily complex, up to the limits Google allows: 

              tie $g, "Tie::Google", $KEY,
                "site:cnn.com allintitle:priest court -judas";

%OPTIONS 

            Any options specified in this hashref will be passed to the
            Net::Google::Search instance. Available options include
            "starts_at", "max_results", "ie", "oe", and "lr". See the
            Net::Google manpage.

The Tied Array Interface

Tieing an array to "Tie::Google" gives you an array of search results. How many search results are returned depends on the value of the "max_results" option defined when the array was tied (or $DEFAULT_BATCH_SIZE if "max_results" was not set), though extending the array of results can be done by growing the array.

$#g = 20;

Will resize the result set to 20 results. If there are more than 20, the ones on the end will be popped off; if there are less than 20, then more will be retrieved.

"Tie::Google" supports all non-additive array operations, including "shift", "pop", and the 3 argument form of "splice" (not the 4 argument version). Specifically unallowed are "unshift", "push", and general assigment.

See the section on "RESULTS" for details about the individual search results.

The Tied Hash Interface

The tied hash interface is similar to the tied array interface, except that there are a bunch of them. Asking for a key in the hash %g initiates a search to Google, with the specified key as the search term:

my $results = $g{'perl apache'};

This initiates a search with "perl apache" as the query. $results is a reference to an array of hashrefs (see the section on "RESULTS" for details about said hashrefs).

Tied hashes support all hash functions, including "each", "keys", and "values". Deleting from the hash is allowed (it removes the search results for the deleted terms), but adding to the hash is not.

There can be many sets of search results stored in a tied hash. To see what this looks like, try this: 

      use Data::Dumper;
      my (%g, $KEY, $dummy);

      tie %g, "Tie::Google", $KEY;
      $dummy = $g{'perl'};
      $dummy = $g{'python'};
      $dummy = $g{'ruby'};

      print Dumper(tied(%g));

Also, for comparison, try: 

      tie @g, "Tie::Google", $KEY, "perl";
      print Dumper(tied(@g));

If "starts_at" or "max_results" are specified during the "tie", these options are carried over into new searches (when a new key is requested from the hash), so plan accordingly. If the "max_value" is set to 1000, for example, then every access of a new key is going to contain 1000 elements, which will be pretty slow.

The Tied Scalar Interface

Do you feel lucky? If so, tie a scalar to "Tie::Google":

tie $g, "Tie::Google", $KEY, "python";

Will give you the top result. This is conceptually similar to using the "I Feel Lucky" button on Google.com's front search interface.

RESULTS

All results (values returned from these tied variables) are hash references; the contents of these hashrefs are based on the "Net::Google::Response" class (see the Net::Google::Response manpage for details). These elements currently are:

All keys are case sensitive, and return exactly what the Net::Google::Response manpage says they do ("Tie::Google" does no massaging of this data).

TODO / BUGS

This module is far from complete, or even fully thought out. TODO items currently include:

to get 100 search results. 

        Although this technique will have the unfortunate side-effect of
        trying to iterate through all the results in Google's database.

          while (<$google>) {
              ...

SEE ALSO

the Net::Google manpage, the DBD::google manpage

AUTHOR

darren chamberlain (<darren@cpan.org>), with some prompting from Richard Soderberg.