Soap Web Service using PHP

http://www.datanom.net/foredrag/php/soap/server/Servers-lecture.pdf
TOC
● Necessary steps when constructing a simple server
● Example server
● Error handling
● Returning the WSDL to clients
● Necessary steps when constructing a complex server
● Mapping complex types
● Example server
● Concluding remarks

Necessary steps when constructing a simple server
1. Write the WSDL
2. Write the service class

3. Add this class to the server:      $server->setClass(“class”); 
4. Activate the server:       $server->handle()

WSDL

xmlns:tns='urn:SayHello' xmlns:soap='http://schemas.xmlsoap.org/wsdl/soap/' xmlns:xsd='http://www.w3.org/2001/XMLSchema' xmlns:soapenc='http://schemas.xmlsoap.org/soap/encoding/' xmlns:wsdl='http://schemas.xmlsoap.org/wsdl/' xmlns='http://schemas.xmlsoap.org/wsdl/'>


    

     



    
        
        

 

    

transport='http://schemas.xmlsoap.org/soap/http'/> 
    
         
            
                                                
                        encodingStyle='http://schemas.xmlsoap.org/soap/encoding/'/>
             
            

                
                            encodingStyle='http://schemas.xmlsoap.org/soap/encoding/'/>
            

     



    
         
    

 
 
Service Class

    class SayHello {
        public function getHello($inmessage) {
            return "Hello $inmessage!"; }
        } //end class

        ini_set("soap.wsdl_cache_enabled", "0"); 
        $server = new SoapServer("SayHello.wsdl"); 
        $server->setClass("SayHello"); $server->handle();
?>

Error handling
$faultcode = 'The actor coursing the fault [client | server | intermediary]';
$faultstring = 'Some human readable text'; 
$faultactor = 'The namespace';
$detail = 'Some machine readable text.';
throw new SoapFault( $faultstring, $faultcode, $faultactor, $detail);

Returning the WSDL 

if (isset($_SERVER['REQUEST_METHOD']) && $_SERVER['REQUEST_METHOD']=='POST') {   
    $soapserver->handle();
} else {

    if (isset($_SERVER['QUERY_STRING']) && 
                strcasecmp($_SERVER['QUERY_STRING'],'wsdl') == 0) { // Return the WSDL
        $wsdl = @implode ('', @file ('some.wsdl'));
        if (strlen($wsdl) > 1) {
            header("Content-type: text/xml");
            echo $wsdl; 
        } else {
            header("Status: 500 Internal Server Error"); header("Content-type: text/plain");
            echo "HTTP/1.0 500 Internal Server Error";
        }

    } else {Some other non-related SOAP error} 
}

Necessary steps when constructing a complex server
1. Write the WSDL for the service
2. Map complex types from WSDL
3. Write the service class
4. Add this class to the server: $server->setClass(“class”); 
5. Activate the server: $server->handle() 

The WSDL

targetNamespace="urn:HostInfo"> 
   
        
             
            
            
             
             
        

     

 


    

 

Map complex types
● Create an associative array for each complex type
● Use the class SoapParam to convert the array to the soap type specified in the WSDL: //SoapParam(mixed data, 'type name from WSDL')

$HostInfo = array( 
    'hostname' => “”, 
    'ip' => “”,    'port' => “”, 
    'datetime' => “”, 
    'PHP_version' => “”
);

return new SoapParam ( $HostInfo, 'hostInfo'); 

Service class 
class HostInfo {
    public function getHostInfo() { 
        $response = array(
            'hostname' => $_SERVER['SERVER_NAME'], 
            'ip' => $_SERVER['SERVER_ADDR'],
            'port' => $_SERVER['SERVER_PORT'], 
            'datetime' => date("l dS of F Y H:i:s T"), 
            'PHP_version' => PHP_VERSION
        );
        return new SoapParam ( $response, 'hostInfo'); 
    }
} 

Add class to server and activate server
ini_set("soap.wsdl_cache_enabled", "0");
$server = new SoapServer("HostInfo.wsdl"); 
$server->setClass("HostInfo");
if (isset($_SERVER['REQUEST_METHOD']) &&
        $_SERVER['REQUEST_METHOD']=='POST') {
    $server->handle();
} else {    $wsdl = @implode ('', @file ('HostInfo.wsdl')); 
    if (strlen($wsdl) > 1) {
        header("Content-type: text/xml");
        echo $wsdl; 
    }
}
@: suppresses error and warnings

Concluding remarks
● All input parameters will be of type stdObject
● Output of any kind is not permitted
● Always provide WSDL for clients
● Input and output are passed in clear text – XML
● If security is an issue use HTTPS – requires the curl module in PHP 
● Encryption is not a part of the standard yet, but work is in progress 
● Always use SoapParam to return complex types
● Provide a class for each usecase – simplifies debugging and gives higher maintainability