[The following excerpt is from Chapter 20 of Pro PHP XML and Web Services by Rob Richards.]
The Services_Google package is simply a wrapper around the SOAP extension and is used to access the Google Web APIs (http://www.google.com/apis/reference.html) for the search engine, spelling suggestions, and cache. To access any of these services, you must obtain a license key by registering for an account. A link to the registration page is available from the previously mentioned URL. Because this package is a wrapper for SOAP, both PHP 5 and the SOAP extension are prerequisites for installing and using this package. Having met these conditions, and because the package is currently in alpha status, you install it using the following:
Once you have installed it, you add support for the package to a script by calling the following:
Note: Google limits you to 1,000 automated queries per day based upon your license key.
This package consists of a single class, Services_Google, that is instantiated by passing your license key as the only argument to the constructor:
Checking Spelling
You can perform a spell check by calling the spellingSuggestion() method. This method takes a string containing the phrase to be checked as its only parameter, and it simply returns a string containing the suggested spelling for the supplied phrase. For example, the following example performs a spell check on the phrase PHP xnl, and it is followed by the resulting phrase suggested by Google’s spell-checking engine:
require_once "Services/Google.php";
/* Google license key */
$key = 'your Google license key';
/* Create instance, passing license key as argument */
$google = new Services_Google($key);
/* Output the resulting suggested spelling */
echo $google->spellingSuggestion('PHP xnl')."\n";
?>
Retrieving Cached Pages
You can retrieve cached pages from Google by calling the getCachedPage() method from an instantiated Services_Google object. The object takes a single parameter, which is a string containing the URL to retrieve the cached page for, and it returns a string containing the cached page.
Caution: As of version 0.1.1 of this package, this method is incompatible with PHP 5.1 and does not return any valid data.
Searching the Web
You can perform Web searches via a Web service just like using Google from a browser by calling the search() method. Once you have an instantiated the Services_Google object, you can use a number of options, listed below, to control various aspects of the search.
Caution: When running the alpha version 0.1.1 of this package with a Web search, you must always set the limit option, and the start option has no bearing on the results returned.
| Option | Default Value | Description |
|---|---|---|
| start | 0 | Zero-based index of the first desired result. |
| maxResults | 10 | Maximum number of results to return for the query. The maximum value per query is 10. |
| limit | FALSE | Although Google limits the maximum number of results for a query, the Services_Google class uses this option to make multiple requests as you move through the returned results, retrieving up to a maximum number of records specified by this option. It is currently mandatory that you use this option, or no results will be returned. |
| filter | TRUE | Activates or deactivates automatic results filtering, which hides similar results and results that all come from the same Web host. |
| restricts | empty | Restricts results to certain countries and/or topics. You can find additional information about using this parameter at http://www.google.ca/apis/reference.html#2_4. |
| safeSearch | TRUE | A Boolean used to filter adult content from the results. |
| language | empty | Restricts the search to documents within one or more languages. Refer to http://www.google.ca/apis/reference.html#2_4 for additional information. |
You set these options using the queryOptions property, which is in fact an array where the keys consist of the options from Table 20-1. For example, using $google as the object, you can limit the results to those that are in the French language by using the following convention:
$google->queryOptions['limit'] = 3; /* Set to make the search work */
Once you have set any and all options, the search() method is called, passing the query string as the argument, as shown here. The query string can contain any type of query that is valid to be used on the Google search page itself.
You can find additional information about writing advanced queries at http://www.google.ca/apis/reference.html#2_2. The actual results when this is executed look like the following:
PHPIndex : <b>PHP</b>, <b>XML</b> et XSLT : point de situation
<b>XML</b> parsing avec <b>PHP</b>
The preceding excerpt is from Chapter 20 of Pro PHP XML and Web Services by Rob Richards.
Pro PHP XML and Web Services is the authoritative guide to using the XML features of PHP 5 and PHP 6. No other book covers XML and Web Services in PHP as deeply as this title. The first four chapters introduce the core concepts of XML required for proficiency, and will bring you up to speed on the terminology and key concepts you need to proceed with the rest of the book. Next, the book explores utilizing XML and Web Services with PHP5. Topics include DOM, SimpleXML, SAX, xmlReader, XSLT, RDF, RSS, WDDX, XML-RPC, REST, SOAP, and UDDI.
