Custom responses for failed actions

[kyork-cl]

We have a couple of cases where we need to know why an action failed. We could come up with some work around with the server log or monitored properties, but that is not an ideal way to handle errors.

This is written such that existing callbacks will not be affected. The err object must have a "properties" member for the behavior to be triggered. I also added a test case to validate the Siren response.

[AdamMagaluk]

To be clear you're proposing in device actions:

TestDriver.prototype.customError = function(cb) {
  cb({statusCode: 401, properties: {message: 'custom error message'}});
}

This would return the following http response:

< HTTP/1.1 401
{
  class: ['action-error'],
  properties: err.properties,
  links: [
    { rel: ['self'], href: env.helpers.url.current() }
  ]
}

Today if anything is passed back in the first parameter to the callback it returns a 500 with no body.

My only issue with the PR is syntax for returning the error. We were thinking about adding a custom error object possibly on the zetta driver that takes a status code and message.

Maybe something like:

TestDriver.prototype.customError = function(cb) {
  cb(new Driver.ActionError(401, 'custom error message'));

 // Also using js Error would also work, could set the message property and assume 500 status code.
 cb(new Error('custom error message')); 

}

[kyork-cl]

I'm fine with that approach, I'll make those changes.

There isn't going to be any problem with actions that previously returned a 500 error with no body having a body after this change?

[AdamMagaluk]

We don't believe so. We'll do some testing with our clients but all so far just look for a non 500 status code.

[kyork-cl]

Added the error. Need to update the callback handler to use it still.

[AdamMagaluk]

This should just be properties not err.properties Message isn't getting passed in the two other cases. Line 544

[AdamMagaluk]

+1 Thanks!