Building and calling webservices using SOAP

admin — Tue, 15/05/2007 - 12:32am

Web services allow you to share data across many platforms and hardware configurations. You create a webservice in PHP, pass the webservice URl to an asp.net program, and it easily calls the webservice methods to get the data from your server. PHP has various methods to create and use webservices. XML-RPC, SOAP and REST are a few. In this article we will find out how we can create and use a webservice using SOAP. Basic database programming knowledge using PHP is assumed.

First let us create a database and in it build a table using the following query.

CREATE TABLE `members` (
`mid` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,
`name` VARCHAR( 255 ) NOT NULL ,
`age` INT NOT NULL
) ENGINE = MYISAM ;

Populate the table with some records

INSERT INTO `members` ( `mid` , `name` , `age` )
VALUES (
NULL , 'Leo', '33'
), (
NULL , 'Ralph', '22'
);

The first thing we need to do is to create the SOAP server. This is the script that will fetch the data from the database and then deliver it to the Client. One wonderful thing about the NuSOAP library is that this same Server script will also create a WSDL document for us.

The first step is to create a function that will fetch the data we want.

function getAge($name) {

    mysql_connect('localhost','user','pass');
    mysql_select_db('db');
    $query = "SELECT age FROM members "
           . "WHERE name = '$name'";
    $result = mysql_query($query);

    $row = mysql_fetch_assoc($result);
    return $row['age'];
}

We must include our NuSOAP library .

require('lib/nusoap.php');

Create the soap server instance

$server = new soap_server();

Define the settings for our WSDL file such as the service name and the namespace

$server->configureWSDL('dbserver', 'urn:ageserv');

Then we register our data fetching function. This step will make the server "aware" of the existence of the getAge method and the values that will pass to and from the method. If you have several methods, you must register each one separately.

$server->register("getAge",
                array('name' => 'xsd:string'),
                array('return' => 'xsd:decimal'),
                'urn:ageserv',
                'urn:ageserv#getAge');

We invoke the webservice using the following lines of code. The first simply checks if $HTTP_RAW_POST_DATA is initialized. If it is not, it initializes it with an empty string. The next line actually calls the service. The web request is passed to the service from the $HTTP_RAW_POST_DATA variable

$HTTP_RAW_POST_DATA = isset($HTTP_RAW_POST_DATA)
? $HTTP_RAW_POST_DATA : '';
$server->service($HTTP_RAW_POST_DATA);

SAVE THIS IN A FILE CALLED dbservice.php. That is our webservice.

{mospagebreak}

To use the webservice we created, first, we must instantiate the NuSOAP client object and pass the WSDL file with the relevant web service definitions into the client.

require_once('lib/nusoap.php');
$wsdl="http://www.webservicehost.com/nusoap/dbservice.php";
$client=new soapclient($wsdl, 'wsdl');

Parameters to pass into the Web service and then remotely call the getAge method. The example shows us sending a name passed via query string into the web service to find out the age.

$param=array(
'name'=>$_GET['val'],
);

Get age by calling the method

$age = $client->call('getAge', $param);

WHEN YOU ARE USING NUSOAP TO CONNECT TO A .NET WEBSERVICE, YOU SHOULD PASS THE PARAMETERS TO THE CALL METHOD IN A DIFFERENT WAY.

.NET WEBSERVICES WRAP ALL THE PARAMETERS IN AN ARRAY CALLED "PARAMETERS"

SO THE CALL METHOD SHOULD BE USED AS FOLLOWS

$age = $client->call('getAge', array('parameters' => $params);

Use the record returned as you require

if($age) {
echo "Age of " .$_GET['val']. " is ".$age;
} else {
echo "Record not found in database";
}

Save it as dbclient.php and test.

Hope you have now got an understanding of how simple it is to create a SOAP Server and Client with NuSOAP. Enjoy !!

Tutorials

Primary links

Building and calling webservices using SOAP

WHEN YOU ARE USING NUSOAP TO CONNECT TO A .NET WEBSERVICE, YOU SHOULD PASS THE PARAMETERS TO THE CALL METHOD IN A DIFFERENT WAY.

User login

Follow Us

Who's online

Who's new