Extract variable with dynamic prefix variable name

[ranomuhamad]

Hi everyone, i have a question about extract variable spesific on <VariablePrefix>. this is my code

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="EV-CreateVarResp">
<Source clearPayload="false">response</Source>
<DisplayName>EV-CreateVarResp</DisplayName>
<IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
<JSONPayload>
<Variable name="name">
<JSONPath>$.name</JSONPath>
</Variable>
</JSONPayload>
<VariablePrefix>{message.header.idcustomer}</VariablePrefix>
</ExtractVariables>

can I grab variable existing to initiate variable prefix to the code above? Is it possible to do that? How can I implement this?

the variable result I want is:

cust8371.name

[dchiesa1 · Accepted solution]

Not with one step. The VariablePrefix element in the ExtractVariables policy does not take a message template. It's a fixed string, so you cannot set a dynamically-determined prefix.

Another way to set a variable is to use AssignMessage and AssignVariable. The syntax for that is:

<AssignMessage name='AM-Example'>
  <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
  <AssignVariable>
    <Name>someName</Name>
    <Template>{this-can-be-dynamic}</Template>
  </AssignVariable>
  ...

And there again, the Name element does not accept a template or ref.  Like the VariablePrefix element in the ExtractVariables policy, it's a fixed string.  

But there is a way to set a variable with a dynamically determined name: the setVariable() call within a JavaScript step. 

// assume a prior ExtractVariables step set a variable
// called 'extracted.name'. 

// Set a new variable with a fixed name.
context.setVariable('fixed-name', 
  context.getVariable('extracted.name'));

// Set a new variable with a dynamically-determined name.
context.setVariable(
  context.getVariable('message.header.idcustomer'), 
  context.getVariable('extracted.name'));

[ranomuhamad]

thanks bro dchiesa1 for your answer, this opened my mind to implement it from another perspective based on your reference. my code now running flawlessly