In addition to standard XPath functions, the ESB supports the following custom functions for working with XPath expressions:
base64Encode() function
The syntax of the function takes the following format.
- base64Encode(string)
It returns the base64 encoded value of the string argument.
Next, see Synapse XPath Variables.
synapse:get-property()
The get-property() function allows any XPath expression used in a configuration to look up information from the current message context. Using the Property mediator, you can retrieve properties from the message context and header.
The syntax of the function takes the following format.
get-property(String propertyName)get-property(String scope, String propertyName)
The function accepts scope as an optional parameter. It retrieves a message property at the given scope, which can be one of the following.
If you provide only the property name without the scope, the default Synapse scope will be used.
Default Scope
Message context properties within the Synapse scope can be retrieved from the default scope. In addition to the user-defined properties, you can retrieve the following special properties from the default scope.
| Name | Return Value |
| To | Incoming URL as a String or empty string («») if a To address is not defined. |
| From | From address as a String or empty string («») if a From address is not defined |
| Action | SOAP Addressing Action header value as a String or empty string («») if a Action is not defined |
| FaultTo | SOAP FautTo header value as a String or empty string («») if a FaultTo address is not defined |
| ReplyTo | ReplyTo header value as a String or empty string («») if a ReplyTo address is not defined |
| MessageID | A unique identifier (UUID) for the message as a String or empty string («») if MessageID is not defined. This id is guaranteed to be unique. |
| FAULT | TRUE if the message has a fault or empty string if message doesn't have a fault |
| MESSAGE_FORMAT | Returns pox, get, soap11, soap12 depending on the message. If a message type is unknown this returns soap12 |
| OperationName | Operation name corresponding to the message. A proxy service with a WSDL can have different operations. If the WSDL is not defined ESB defines fixed operations |
Axis2 scope
Message context properties within the Axis2 scope can be retrieved from the Axis2 scope.
Syntax:get-property('axis2', String propertyName)
Transport scope
Message context properties within the transport scope can be retrieved from the transport scope.
Syntax:get-property('transport', String propertyName)
Registry scope
Properties within the registry can be retrieved from the registry scope.
Syntax:get-property('registry', String registryPath@propertyName)get-property('registry', String registryPath)
System scope
Java System properties can be retrieved from the system scope.
Syntax:get-property('system', String propertyName)
Note: system scope is only available in WSO2 ESB 4.8.0 or later versions