Lets say you have a service with the following soap request and you need to validate the input message, through a proxy service, for those kind of instances you can use WSO2 ESB Validate Mediator.
For this demonstration I am going to create a proxy service which is deployed and hosted under my tenant in StratosLive you can use the same service for sample purposes. This is a service which takes an input string and send a response along with the given input String.
My End point is
http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService/
The WSDL for my Service
http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService?wsdl
First Lets Create a proxy service which access this service
<proxy name="MyValidatorProxy"
transports=
"https http"
startOnLoad=
"true"
trace=
"disable">
<description/>
<target>
<inSequence>
<log level=
"full">
<property name=
"Message" value=
"Inside Insequance"/>
</log>
<send>
<endpoint>
<address uri=
"http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService/"/>
</endpoint>
</send>
</inSequence>
<outSequence>
<send/>
</outSequence>
</target>
<publishWSDL uri=
"http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService?wsdl"/>
</proxy>
Go to ESB Management Console and copy paste the following code in Source View (Under Main -> Service Bus -> Source View) and click on update.
This will create a proxy service which will create the service I hosted in my tenant.
You can invoke this service by going into Services List and click on try it. Which is a client we use to invoke the service.
Now When you click on the try-it, you will get redirected to a page which has a request and a response.
So for a given request like this
<body>
<p:greet xmlns:p=
"http://www.wso2.org/types">
<!--0 to 1 occurrence-->
<name>Amani
</name>
</p:greet>
</body>
You should get a response like this.
<ns:greetResponse xmlns:ns="http://www.wso2.org/types">
<return>Hello World, Amani !!!</return>
</ns:greetResponse>
So lets see how we can validate the request. Lets say you want to make sure the value of the name element is not empty and you want to enforce that for every service innovation there must be a value for the Name element. Then you need to use the ESB validate Mediator.
In order to create a proxy with a validate mediator we need to create a XSD schema. I have created a schema to validate the name element of the request.
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:ns1="http://org.apache.axis2/xsd" xmlns:ns="http://www.wso2.org/types"
attributeFormDefault=
"qualified" elementFormDefault=
"unqualified"
targetNamespace=
"http://www.wso2.org/types">
<xs:element name=
"greet">
<xs:complexType>
<xs:sequence>
<xs:element minOccurs=
"1" name=
"name" >
<xs:simpleType>
<xs:restriction base=
"xs:string">
<xs:minLength value=
"1" />
</xs:restriction>
</xs:simpleType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Here the main thing you need to focus is this part
<xs:element minOccurs="1" name="name" >
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:minLength value="1" />
</xs:restriction>
</xs:simpleType>
</xs:element>
We are using the restriction element which says to restrict the type as String and the input should be a non-zero value (basically this means element cannot be empty). Now we need to upload this in the registry.
Uploading the validation schema in the registry.
Go to Browse in the Registry menu. And there click on config and under that click on Add New Resource. And upload the file as xsd file.
Add Validator Mediator
<validate>
<schema key=
"conf:/HelloSchema.xsd"/>
<on-fail>
<makefault version=
"soap11">
<code xmlns:tns=
"http://www.w3.org/2003/05/soap-envelope" value=
"tns:Receiver"/>
<reason value=
"Invalid Request!!!"/>
<role/>
</makefault>
<log level=
"full" />
<property name=
"RESPONSE" value=
"true"/>
<header name=
"To" action=
"remove"/>
<send/>
<drop/>
</on-fail>
</validate>
In here we add the Schema from the registry, If the validation fails it will send a message saying "Invalid Request" and we will terminate the flow using the drop mediator.
Now we will ad this validate mediator in the in sequence of our proxy service.
<proxy xmlns="http://ws.apache.org/ns/synapse" name="MyValidatorProxy" transports="https,http" statistics="disable" trace="disable" startOnLoad="true">
<target>
<inSequence>
<log level=
"full">
<property name=
"Message" value=
"Inside Insequance"/>
</log>
<validate>
<schema key=
"conf:/HelloSchema.xsd"/>
<on-fail>
<makefault version=
"soap11">
<code xmlns:tns=
"http://www.w3.org/2003/05/soap-envelope" value=
"tns:Receiver"/>
<reason value=
"Invalid Request!!!"/>
<role/>
</makefault>
<log level=
"full"/>
<property name=
"RESPONSE" value=
"true"/>
<header name=
"To" action=
"remove"/>
<send/>
<drop/>
</on-fail>
</validate>
<send>
<endpoint>
<address uri=
"http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService/"/>
</endpoint>
</send>
</inSequence>
<outSequence>
<send/>
</outSequence>
</target>
<publishWSDL uri=
"http://appserver.stratoslive.wso2.com/services/t/amani123.com/HelloService?wsdl"/>
<description></description>
</proxy>
Now if you invoke this using try it without a content in the name element you will get the message as Invalid Request.
Request
<body>
<p:greet xmlns:p="http://www.wso2.org/types">
<!--0 to 1 occurrence-->
<name></name>
</p:greet>
</body>
Response
<soapenv:Fault xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<faultcode>tns:Receiver</faultcode>
<faultstring>Invalid Request!!!
</faultstring>
</soapenv:Fault>
