electricimp / azureiothub Goto Github PK

Refer to http://fredkschott.com/post/2014/03/understanding-error-first-callbacks-in-node-js/. In my opinion, "error-first" callbacks are the appropriate pattern and are worth making a major release of the class over.

retrieveTwinProperties(onRetrieved) follows this pattern with its error, reportedProps, desiredProps signature. All of the callbacks that only take a single parameter of error obviously do too.

However, 2 callbacks are offenders...

• The onUpdated callback signature for client.updateTwinProperties uses onUpdated(**props**, error) instead of being onUpdated(error, props)
• The onSent callback signature for client.sendMessage is also inverted

Its a minor code/documentation effort for the library and since the libraries are versioned it seems like something that should be considered? Thoughts?

most recent version now REST API version for IoT Hub is "2016-02-03”
current code uses "2015-08-15-preview"

I have a use case for using a direct method that requires async communication with the device (using something like message manager). Unfortunately, the onMethod callback stipulates that the "The callback MUST return an instance of the of the AzureIoTHub.DirectMethodResponse" in order to reply.

I would like to propose that https://github.com/electricimp/AzureIoTHub/blob/master/AzureIoTHub.agent.lib.nut#L1342 be modified to respect a return value of an instanceof promise in addition to the synchronous callback that is allowed today. The promise would need to resolve with a AzureIoTHub.DirectMethodResponse (perhaps within a timeout?) in order to send the response to IoT Hub.

The documentation still lists the previous convention (error-last) on the callbacks, please update