Introduction into SOAP, setting up a simple webservice with PHP SOAP
I was asked to create a simple webservice that would allow us to transfer a intranet post to an external CMS. In this post I will explain the steps you must take to set-up a simple webservice with the PHP SOAP extension.
The first step, create a simple class that we will use to request data from
We will create a class with one method that returns a string with the parameter we called it. The method will accept one parameter and will check if the value is correct.
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<?php
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/**
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* Blog service class
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*/
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class BlogService
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{
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/**
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* Return a blogpost
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*
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* @param string $sID
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* @return string test data
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*/
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public function getItem($sID)
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{
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$iID = (int)$sID;
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// Check if we requested a valid blogpost id
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return new SoapFault(‘Server’, ‘Blogpost with id ‘.$iID.‘ not found!’);
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}
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return ‘Blogpost with id ‘.$iID;
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}
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}
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?>
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Nothing special here, notice that we don’t throw a normal exception but return the SoapFault instead so we can handle the error clientside.
The second step, create a WSDL document
The WSDL document is a simple XML document that describes:
- the service itself
- the operations of the service
- the data types used in the service
The WSDL will describe our method getItem from our Blog service class so we can call it later on.
So how does this WSDL thing look like?
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// Init the server
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$oServer = new SoapServer(‘blog.wsdl’);
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// Register the blog service class and all the methods
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$oServer->setClass(‘BlogService’);
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// Rock ‘n roll
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$oServer->handle();
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The fourth and final step, test our webservice
Its a good idea to test the webservice with a program like soapUI, it often can provide some additional information when troubleshooting. (They have a free version available on their website).
To test our webservice in PHP we can use the following code:
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$oClient = new SoapClient(
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// Url to our wsdl, http://{siteUrl}/webservice/index.php?wsdl is also possible
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‘{siteUrl}/webservice/blog.wsdl’,
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‘trace’ => true,
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‘exceptions’=> true
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));
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try {
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$aResult = $oClient->getItem(4);
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} catch (SoapFault $e) {
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}
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You should see a SOAP fault, because the id number 4 we gave to the getItem function didn’t exist in our Blog service class. Change the value to 1,2,3 or 5 and you should get a nice response back.
Another pretty neat function is $oClient->__getFunctions(); it will return all the function that are available in the webservice.
This was just a short introduction to SOAP, a lot more is possible with SOAP.
Special thanks to David Zuelke for the nice SOAP introduction at the PHPbenelux conference 2010.
Example files:
Webservice.rar
Just deploy the example files on your webserver, change the {siteUrl} values in the files with your domain and call the client.php
