Cache Cow - PHP

The Google Web APIs allow developers to build SOAP-basedapplications driven off Google's unique indexing and searchcapabilities. And since there are now quite a few PHP classes designedfor SOAP transactions over HTTP, integrating the two has never beensimpler. This article explains how.

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By: Harish Kamath, (c) Melonfire

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July 16, 2002

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Google also allows you to retrieve cached Web pages from its database, via the exposed doGetCachedPage() procedure. Here's a quick example, which demonstrates retrieval of the URL "http://www.xmlphp.com/" from the Google cache.

<?php
// include the class
include("nusoap.php");
// create a instance of the SOAP client object
$soapclient = new soapclient("http://api.google.com/search/beta2");
// uncomment the next line to see debug messages
// $soapclient->debug_flag = 1;
// set up an array containing input parameters to be
// passed to the remote procedure
$params = array(
'key' => 'your-google-license-key-xxxxxxxx',  // Google
license key
'url'   => $_GET['u'],   // URL to retrieve
);
// invoke the method on the server
$result = $soapclient->call("doGetCachedPage", $params,
"urn:GoogleSearch", "urn:GoogleSearch"); 
if ($result)
{
// fault?
if (is_array($result) && $result['faultstring'])
{
// display error
echo $result['faultstring'];
}
else
{
// decode return value using base64
// and display
echo base64_decode($result);
}
}
?>

The doGetCachedPage() procedure requires two parameters - your license key, and the URL to be retrieved. This cached content of this URL is retrieved as a base64-encoded data block, which needs to be decoded before it can be displayed. Luckily, PHP comes with a built-in base64_decode() function, which does just that.

Now, if you pass the script above the URL "http://www.xmlphp.com", like this,


http://localhost/retrieve.php?u=http://www.xmlphp.com

here's what you'll see:

You can link the doGoogleSearch() and doGetCachedPage() procedures to allow Web pages matching your search to be retrieved from the cache, in much the saw way as Google.com does. All that's needed is a slight modification to the search engine script created a couple pages back:

<?
// form submitted
// init soap client and call doGoogleSearch
// iterate through result
foreach ($result['resultElements'] as $r)
{
echo "<li><a href=" . $r['URL'] . ">" . $r['title'] .
"</a>";
echo "<br>";
echo $r['snippet'] . "(" . $r['cachedSize'] . ")";
echo "<br>";
echo "<a href=retrieve.php?u=" . $r['URL'] . ">Get
cached page</a>";
echo "<p>";
}
// snip
?>

As you can see, I've added a link below each displayed match to the script "retrieve.php", which is passed the URL to be retrieved from the cache. This URL is sent to the doGetCachedPage() procedure as a procedure argument, and the result is decoded and displayed.{mospagebreak title=Spelling Bee} Finally, Google also allows you to vet spellings, via its doSpellingSuggestion() procedure. Here's a quick example:

<html>
<head><basefont face="Arial"></head>
<body>
<?php
if (!$_POST['p'])
{
?>
<h2>Spell-check</h2>
<form action="<?=$_SERVER['PHP_SELF']?>" method="post">
Check term: <input type="text" name="p">
</form>
<?
}
else
{
// include the class
include("nusoap.php");
// create a instance of the SOAP client object
$soapclient = new
soapclient("http://api.google.com/search/beta2");
// uncomment the next line to see debug messages
// $soapclient->debug_flag = 1;
// set up an array containing input parameters to be
// passed to the remote procedure
$params = array(
'key' => 'your-google-license-key-xxxxxxxx',
// Google
license key
'phrase'   => $_POST['p']
// term to check
);
// invoke the method on the server
$result = $soapclient->call("doSpellingSuggestion", $params,
"urn:GoogleSearch", "urn:GoogleSearch"); 
// print the results of the search
if ($result)
{
if (is_array($result) && $result['faultstring'])
{
?>
<h2>Error</h2>
<? echo $result['faultstring'];?>
<? 
}
else
{
echo "Google suggests <b>" . $result . "</b> for
the term <b>" . $_POST['p'] . "</b>";
}
}
else
{
echo "No suggestion";
}
}
?>
</body>
</html>

In this case, the doSpellingSuggestion() procedure expects two arguments - your Google license key, and the term to be checked against Google's internal dictionary. You can use this to build a rudimentary Web-based spell-checker (among other things). This spell-checker is actively used on the Google.com Web site, to identify and warn you about potential spelling errors in your query.

Here's what the output looks like: