Created
August 9, 2015 17:48
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var mosca = require("mosca"); | |
var mqtt = require("mqtt"); | |
function promiseMosca(){ | |
var moscaOpts = { | |
http:{ | |
port:3000, | |
static:false, | |
bundle:false | |
}, | |
onlyHttp:true | |
}; | |
return new Promise(function(resolve, reject){ | |
var mqttServer = new mosca.Server(moscaOpts); | |
mqttServer.on("ready", function(){ | |
resolve(mqttServer); | |
}); | |
}); | |
} | |
function promiseMosquitto(){ | |
return Promise.resolve(); | |
} | |
function promiseClient(){ | |
return new Promise(function(resolve, reject){ | |
var mqttClient = mqtt.connect("ws://localhost:3000"); | |
mqttClient.on("connect", function(){ | |
resolve(mqttClient); | |
}); | |
}); | |
} | |
function promiseReceipt(client){ | |
return new Promise(function(resolve, reject){ | |
client.on("message", function(topic, message, packet){ | |
resolve([topic, message.toString()]); | |
}); | |
}); | |
} | |
function promiseSubscription(client, topic){ | |
return new Promise(function(resolve, reject){ | |
client.subscribe(topic, {qos:1}, function(err, granted){ | |
var result = Array.prototype.slice.call(arguments); | |
resolve(result); | |
}); | |
}); | |
} | |
function promisePublication(client,topic,message){ | |
return new Promise(function(resolve, reject){ | |
client.publish(topic, message, {qos:1, retain:true}, function(){ | |
resolve(Array.prototype.slice.call(arguments)); | |
}); | |
}); | |
} | |
var testTopic = "Hello", | |
testMessage = "World"; | |
//var serverPromise = promiseMosca(); | |
var serverPromise = promiseMosquitto(); | |
var testPromise = serverPromise | |
.then(function() { | |
return promiseClient() | |
}) | |
.then(function(receiver) { | |
var receivePromise = promiseReceipt(receiver); //initialised before publication so no events are missed | |
return Promise.resolve() | |
.then(function(){ | |
return promiseClient(); | |
}) | |
.then(function(sender){ | |
return promisePublication(sender,testTopic,testMessage); | |
}) | |
.then(function(){ //move this clause to first in the list, and Mosca delivers the message! | |
return promiseSubscription(receiver, testTopic); | |
}) | |
.then(function(){ | |
return receivePromise; //promise initialised earlier is passed back | |
}); | |
}); | |
testPromise.then(function(receiveResult){ | |
console.log("Message Received: " + JSON.stringify(receiveResult)); | |
}); |
I should underline that the test case fails by never completing the callback, (so it appears as a hang), although the original version used Q to force the promise to concretely be rejected after a known timeout, the library dependency on Q has been removed.
Don't you need a persistence to deliver retained message with Mosca?
Thanks for taking the time to look at this!. Providing a configuration like the one below indeed resolves the issue altogether.
Although I previously had a persistence configuration (and removed it to make a more minimal test case) there must have been something wrong with the configuration I provided. This one is minimal but works...
var moscaOpts = {
http:{
port:3000,
static:false,
bundle:false
},
persistence: {
factory: mosca.persistence.Memory
},
onlyHttp:true
};
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The code above is demonstrated to work where there is a localhost Mosquitto broker (configured with Websocket support) on port 3000.
It outputs...
However, if you shut down the Mosquitto websockets server on 3000, and change the serverPromise to be promiseMosca() instead of promiseMosquitto() then the test case fails.