How to expose error and trace in Plumber?

[memery]

I want to expose a full trace and error message from plumber instead of the generic {"error":["500 - Internal server error"]}

The documentation suggests I should be able to use setErrorHandler but not where that should be placed or what should be placed in it.

---

^{Referred here by plumber's GitHub}

[hoelk]

If your endpoint already returns JSON, the easiest way is to catch the error and return a JSON object that contains all the error info you need. something like:

@endpoint
function(){

  tryCatch(..., error = function(e) {
    res$status = 400  # the response object that is always available in plumber functions
    return(list(error = e, traceback = ...))
  })
}

if your endpoint returns something else than JSON your out of luck (you can only have one serializer by endpoint). I don't think the ErrorHandler stuff works yet (or if it does, its not documented sufficiently)