MML

Message Manipulation Language

Usage

1. Add mml.js to the proxy, environment, or org.

2. Where you want to do the extract and/or assign work, place a JavaScript callout policy.

3. Set the JavaScript ResourceURL to refer to mml.js: <ResourceURL>jsc://mml.js</ResourceURL>

4. Use a Property named script to manipulate messages and variables:

    <Properties>
      <Property name="script">
        copy request.verb myverb   # create a flow variable
        copy myverb request.header.abc   # create a header
        copy request.queryparam.x request.header.xquery   # copy a queryparam to a header
        message created
        jsonpath request "$..author" firstAuthor
        copy queryparam.x created.header.xQuery
        copy code:(new Date()).toString() created.header.computedDate
        delete q.x
      </Property>
</Properties>

Commands

• copy src tgt
• copy "literal" tgt
• copy code:(new Date()).toString() tgt
  • Currently accepts code in the src term only, indicated by the leading "code:". This will break if the code contains the contents of the other two terms, e.g. copy code:makeacopy() header.x will break, because very stupid parser.
• message msg
  • Creates a new message with the name provided in msg (Note that, due to a limitation in the JavaScript Callout, this will not be an empty message; it is a copy of the current message object flow variable.)
• jsonpath inputMsg expression tgtVar
  • Evaluates the expression on the JSON body of inputMsg and puts the result into tgtVar.
    • tgtVar only supports variables at the moment; headers are not supported yet.
    • If the JSONPath expression returns an array, you will only get the first element of the array.
    • This is a first pass at JSONPath symtax and implementation. It needs to be refined.
• delete tgt
• comments are initiated by a # at any point in a line

Syntactic sugar

• If not specified, message (request or response, depending on the flow) is assumed.
  • header.abc is short for message.header.abc
• Header can be shortened to hdr or h.
  • hdr.abc is the same as message.header.abc
  • h.abc is the same as message.header.abc
• Queryparam can be shortened to query, qp, or q
  • All of these are equivalent
    • message.queryparam.x
    • queryparam.x
    • query.x
    • qp.x
    • q.x

Issues and enhancements

• Support for regex
• Support for form and body/payload variables
• Support for JSONPath
• Support for XPath
• Support for substring extraction with no{yes}no syntax
• Support for handlebars templates
• Externalize scripts (load from resource or URL, not just hardcoded script)
• Potential collision if message object has same name as another variable?
• Accept closures for doing more complex manipulation of parameters
• Mock context, so that unit tests can be created