Support URI connections

[wolfeidau]

The client does not seem to support URI connections, while there is no common MQTT URI scheme, supporting mqtt://, mqtts:// and tcp:// URI's would make it easier to
use this client in heroku and other PaaS environments.

Any thoughts on this?

See njh/ruby-mqtt#31 for previous discussions on this.

[mcollina]

I would like to get some feedback from @knolleary and @ralight on the URL
format.
Actually I have implemented it a few times myself so it makes complete
sense to have it in here.

The main thing we are missing is a new 'createClient' interface that can
handle both normal and encrypted, with an object-based parameters (not
positional).

[wolfeidau]

Yeah I would encourage you to consider moving to something like.

var mqtt = require('mqtt')

// either mqtt:// or tcp://
client = mqtt.connect('mqtt://guest:guest@localhost');

With an options argument available to support extra params for things like TLS related params.

var mqtt = require('mqtt')

var options = {
  rejectUnauthorized : true, 
};

// either mqtts:// or ssl:// 
client = mqtt.connect('mqtts://guest:guest@localhost', options);

This would avoid breaking the existing code while offering a nice clean interface for connecting using a URI.

[knolleary]

@mcollina this was discussed recently on the MQTT mailing list. A summary of the discussion was put on the wiki here.

The piece that is missing is how to specify the client-id in the uri. The only place for it is as a ?clientId= style parameter, which doesn't look elegant to me...

Admittedly this is all informal - I will bring it up on the OASIS list for discussion to see if we can get something added in time for the 3.1.1 doc.

[knolleary]

Have raised an issue against 3.1.1 - https://tools.oasis-open.org/issues/browse/MQTT-203

[mcollina]

@knolleary do you think the clean flag should be in the URI, in the same way client id is specified?