Using The Google Web APIs With PHP - Plugging In (
Page 4 of 9 )
Google has made
three methods available in their Web API. Here's what they look
like:
doGoogleSearch() - search for a specified term in the Google
database;
doGetCachedPage() - retrieve a page from the Google
cache;
doSpellingSuggestion() - retrieve a spelling suggestion from
Google.
This might not seem like much, but you'll soon see that it's more
than enough to build some fairly powerful applications. Take a look at the
following example, which provides a gentle introduction to running a search
query on Google with PHP:
<?php
// include the class
include("nusoap.php");
// create a instance of the SOAP client object
// remember that this script is the client,
// accessing the web service provided by Google
$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
'q' => 'melonfire', // search term
'start' => 0, // start from result
n
'maxResults' => 10, // show a total of n
results
'filter' => false, // remove similar
results
'restrict' => '', // restrict by topic
'safeSearch' => false, // remove adult
links
'lr' => '', // restrict by
language
'ie' => '', // input encoding
'oe' => '' // output encoding
);
// invoke the method on the server
$result = $soapclient->call("doGoogleSearch", $params,
"urn:GoogleSearch", "urn:GoogleSearch");
// print the results of the search
print_r($result);
?>
The first order of business is to include the SOAP class
which contains all the methods needed to access SOAP services. I've used NuSOAP
here, but I'll show you the same thing using the PEAR class a little further
down.
<?php
// include the class
include("nusoap.php");
?>
Now, in this SOAP universe, Google provides the SOAP server,
and this PHP script works as the client. So, the next step is to instantiate
this client, using the class constructs provided by NuSOAP.
<?php
// create a instance of the SOAP client object
$soapclient = new soapclient("http://api.google.com/search/beta2");
?>
The class constructor accepts a single parameter, which is
the URL of the SOAP service to be accessed (this is sometimes referred to by
geeks as the "endpoint").
All that remains is to send a request to the
SOAP server - something easily accomplished by the class' call() method.
<?php
// invoke the method on the server
$result = $soapclient->call("doGoogleSearch", $params,
"urn:GoogleSearch", "urn:GoogleSearch"); ?>
The call() method accepts four arguments - the name of the
remote procedure to be invoked, an array containing arguments for this remote
procedure, a method namespace and a SOAPAction value. The remote procedure name
here is doGoogleSearch(), and the list of arguments to be passed to it are
stored in the $params array, which looks like this:
<?php
// 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
'q' => 'melonfire', // search term
'start' => 0, // start from result
n
'maxResults' => 10, // show a total of n
results
'filter' => false, // remove similar
results
'restrict' => '', // restrict by topic
'safeSearch' => false, // remove adult
links
'lr' => '', // restrict by
language
'ie' => '', // input encoding
'oe' => '' // output encoding
);
?>
Here's what those arguments mean:
"key" - your Google
license key;
"q" - the query string;
"start" - the index number of
the first result to display;
"maxResults" - the maximum number of matches
to display (limited to a maximum of 10);
"filter" - a Boolean indicating
whether or not to display matches which are similar to each
other;
"restrict" - limit the search to a specific section of the Google
database;
"safeSearch" - filter out adult content from the result
set;
"lr" - limit the search to a specific language;
"ie" - the
character encoding of the query string;
"oe" - the character encoding of
the result set.
If you take a look at the internals of the SOAP class,
you'll see that the call() method uses the arguments passed to it to generate a
SOAP request, which looks something like this:
POST /search/beta2 HTTP/1.0
User-Agent: NuSOAP v0.6
Host: api.google.com
Content-Type: text/xml
Content-Length: 946
SOAPAction: "urn:GoogleSearch"
<?xml version="1.0"?>
<SOAP-ENV:Envelope
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:si="http://soapinterop.org/xsd"
xmlns:galactivism="urn:GoogleSearch">
<SOAP-ENV:Body>
<galactivism:doGoogleSearch>
<key xsi:type="xsd:string">your-google-license-key-xxxxxxxx</key>
<q xsi:type="xsd:string">melonfire</q>
<start xsi:type="xsd:int">0</start>
<maxResults xsi:type="xsd:int">10</maxResults>
<filter xsi:type="xsd:boolean">0</filter>
<restrict xsi:type="xsd:string"></restrict>
<safeSearch xsi:type="xsd:boolean">0</safeSearch>
<lr xsi:type="xsd:string"></lr>
<ie xsi:type="xsd:string"></ie>
<oe xsi:type="xsd:string"></oe>
</galactivism:doGoogleSearch>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
This request packet is transmitted to the SOAP server using
the POST method, and a server response packet is transmitted back to the client.
Here's what one such packet might look like:
HTTP/1.0 200 OK
Date: Fri, 21 Jun 2002 05:51:46 GMT
Content-Length: 10920
Content-Type: text/xml; charset=utf-8
Server: e h c a p a
Via: 1.1 HathCache (NetCache NetApp/5.0.1R2D3)
<?xml version='1.0' encoding='UTF-8'?>
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/1999/XMLSchema">
<SOAP-ENV:Body>
<ns1:doGoogleSearchResponse xmlns:ns1="urn:GoogleSearch"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<return xsi:type="ns1:GoogleSearchResult">
<documentFiltering xsi:type="xsd:boolean">false</documentFiltering>
<estimatedTotalResultsCount
xsi:type="xsd:int">3880</estimatedTotalResultsCount>
<directoryCategories
xmlns:ns2="http://schemas.xmlsoap.org/soap/encoding/"
xsi:type="ns2:Array" ns2:arrayType="ns1:DirectoryCategory[0]">
</directoryCategories>
<searchTime xsi:type="xsd:double">0.247468</searchTime>
<resultElements xmlns:ns3="http://schemas.xmlsoap.org/soap/encoding/"
xsi:type="ns3:Array" ns3:arrayType="ns1:ResultElement[10]">
<item xsi:type="ns1:ResultElement">
<cachedSize xsi:type="xsd:string">6k</cachedSize>
<hostName xsi:type="xsd:string"></hostName>
<snippet xsi:type="xsd:string"> <b>...</b> Check out. what
we've cooked up in our brand-new PHP section. Copyright
1998-2002<br> <b>Melonfire</b>. All rights reserved
Terms and Conditions | Feedback. </snippet> <directoryCategory
xsi:type="ns1:DirectoryCategory"> <specialEncoding
xsi:type="xsd:string"></specialEncoding>
<fullViewableName
xsi:type="xsd:string">Top/Computers/Internet/Web_Design_and_Development/
Desi
gners/M</fullViewableName>
</directoryCategory>
<relatedInformationPresent
xsi:type="xsd:boolean">true</relatedInformationPresent>
<directoryTitle xsi:type="xsd:string"><b>Melonfire</b>
</directoryTitle>
<summary xsi:type="xsd:string">A production house with business
divisions focusing on content production and Web development. </summary>
<URL xsi:type="xsd:string">http://www.melonfire.com/</URL>
<title xsi:type="xsd:string"><b>melonfire</b>!</title>
</item>
<item xsi:type="ns1:ResultElement">
<cachedSize xsi:type="xsd:string">11k</cachedSize>
<hostName xsi:type="xsd:string"></hostName>
<snippet xsi:type="xsd:string"> <b>...</b> Copyright
1998-2002 <b>Melonfire</b>. All rights reserved<br>
Terms and Conditions | Feedback. </snippet> <directoryCategory
xsi:type="ns1:DirectoryCategory"> <specialEncoding
xsi:type="xsd:string"></specialEncoding>
<fullViewableName xsi:type="xsd:string"></fullViewableName>
</directoryCategory>
<relatedInformationPresent
xsi:type="xsd:boolean">true</relatedInformationPresent>
<directoryTitle xsi:type="xsd:string"></directoryTitle>
<summary xsi:type="xsd:string"></summary>
<URL
xsi:type="xsd:string">http://www.melonfire.com/community/columns/trog/ar
chiv
es.php?category=PHP</URL>
<title xsi:type="xsd:string">The <b>Melonfire</b> Community
- Trog</title> </item>
-- snip --
</resultElements>
<endIndex xsi:type="xsd:int">10</endIndex>
<searchTips xsi:type="xsd:string"></searchTips>
<searchComments xsi:type="xsd:string"></searchComments>
<startIndex xsi:type="xsd:int">1</startIndex>
<estimateIsExact xsi:type="xsd:boolean">false</estimateIsExact>
<searchQuery xsi:type="xsd:string">melonfire</searchQuery>
</return>
</ns1:doGoogleSearchResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
This response packet is decoded by the client into a native
PHP structure, which can be used within the script. At the moment, all I'm doing
is printing it - and here's what the output looks like:
Array
(
[documentFiltering] => false
[estimatedTotalResultsCount] => 3880
[directoryCategories] =>
[searchTime] => 0.05159
[resultElements] => Array
(
[0] => Array
(
[cachedSize] => 6k
[hostName] =>
[snippet] => <b>...</b> Check out. what we've
cooked up in our brand-new PHP section. Copyright 1998-2002<br>
<b>Melonfire</b>. All rights reserved Terms and Conditions | Feedback.
[directoryCategory] => Array
(
[specialEncoding] =>
[fullViewableName] =>
Top/Computers/Internet/Web_Design_and_Development/Designers/M
)
[relatedInformationPresent] => true
[directoryTitle] => <b>Melonfire</b>
[summary] => A production house with business
divisions focusing on content production and Web development.
[URL] => http://www.melonfire.com/
[title] => <b>melonfire</b>!
)
[1] => Array
(
[cachedSize] => 11k
[hostName] =>
[snippet] => <b>...</b> Copyright 1998-2002
<b>Melonfire</b>. All rights reserved<br> Terms and Conditions |
Feedback.
[directoryCategory] => Array
(
[specialEncoding] =>
[fullViewableName] =>
)
[relatedInformationPresent] => true
[directoryTitle] =>
[summary] =>
[URL] =>
http://www.melonfire.com/community/columns/trog/archives.php?category=PH
P
[title] => The <b>Melonfire</b> Community - Trog
)
// remaining array elements snipped out //
)
[endIndex] => 10
[searchTips] =>
[searchComments] =>
[startIndex] => 1
[estimateIsExact] => false
[searchQuery] => melonfire
)
Obviously, this is not very useful - but we're just getting
started. Flip the page, and I'll show you how to massage all this raw data into
something resembling a search results page.
