XPath Extension Functions

There are two custom functions supported by the ESB as follows:

synapse:get-property() function
base64Encode() function

`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 property mediator, you can retrieve properties previously set, and/or information from the Synapse, Axis2 message contexts or transport 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 synapse, axis2 or transport. If you provide only the property name without the scope, the default Synapse scope will be used.

synapse:get-property( [(axis2 | axis2-client | transport),] <property_name> [,<dateformat>] )

You can use the get-property() function to retrieve Axis2 message context properties or transport headers. For example, synapse:get-property('transport', 'USER_AGENT'). Given below are special properties supported by the get-property() function.

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

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.