How to retrive property and process/iterate them in synapse using xpath and script mediator - WSO2 ESB

Sometimes we need to retrieve properties and manipulate them according to custom requirement. For this i can suggest you two approaches.



01. Retrieve roles list and fetch them using script mediator.

//Store Roles into message context
 <property name="ComingRoles" expression="get-property('transport','ROLES')"/>

//Or you can you following if property is already set to default message context
 <property name="ComingRoles" expression="get-property(''ROLES')"/>


//process them inside script mediator
<script language="js">
            var rolelist = mc.getProperty('ComingRoles');
//Process rolelist and set roles or required data to message context as follows. Here we set same role set
            mc.setProperty('processedRoles',rolelist);
</script>
 <log>
            <property name="Processed Roles List" expression="get-property('processedRoles')"/>
</log>

02. Retrieve roles list and fetch them using xpath support provided.

//Retrive incoming role list
  <property name="ComingRoles" expression="get-property('transport','ROLES')"/>

//Or you can you following if property is already set to default message context
 <property name="ComingRoles" expression="get-property(''ROLES')"/>

//Fetch roles one by one using xpath operations
         <property name="Role1"
                   expression="fn:substring-before(get-property('ComingRoles'),',')"/>
         <property name="RemainingRoles"
                   expression="fn:substring-after(get-property('transport','ROLES'),',')"/>

//Fetch roles one by one using xpath operations
         <property name="Role2"
                   expression="fn:substring-before(get-property('RemainingRoles'),',')"/>
         <property name="RemainingRoles"
                   expression="fn:substring-after(get-property('RemainingRoles'),',')"/>

//Fetch roles one by one using xpath operations
         <property name="Role3" expression="(get-property('RemainingRoles'))"/>

//Then log all properties using log mediator
         <log>
            <property name="testing" expression="get-property('Role1')"/>
         </log>
         <log>
            <property name="testing" expression="get-property('Role2')"/>
         </log>
         <log>
            <property name="testing" expression="get-property('Role3')"/>
         </log>

//Check whether roles list having String "sanjeewa". If so we will set isRolesListHavingSanjeewa as true else its false.
         <log>
            <property name="isRolesListHavingSanjeewa"
                      expression="fn:contains(get-property('transport','ROLES'),'sanjeewa')"/>
         </log>

You will find xpath expressions and sample here(http://www.w3schools.com/xpath/xpath_functions.asp)