A new way to write IoT application server code.

devify-server, or Devify in a short, is a simple IoT server boilerplate.

Devify is extremely light weight, and is very easy to use. It aims to help developers to create IoT application servers, faster.

Devify is an open source project to develop the boilerplates for getting started with IoT cloud servers. It gets you up to speed using IoT and web technologies.

Devify open source project, or Devify, is a software framework. Its goal is to create a new way to write IoT server code.

A cli tool devify-cli is available for getting started with devify.

$ npm install -g devify-cli
$ devify new <new_project_dir>
$ cd <new_project_dir> && npm install
$ node esp8266-coap-server.js 

This section introduces a new way to write a CoAP server for getting data from an NodeMCU (ESP8266) device.

The following instructions show how to connect NodeMCU to your localhost (PC/Notebook) and send ADC data to localhost over CoAP.

$ npm install -g devify-cli 

devify-cli a cli app aimed to get you speed up.

$ devify esp_air_iot

Create a new Devify project by devify-cli. Devify-cli will automatically create a new folder and download the project template at this folder. The folder name is esp_air_iot at this example.

Please make sure that git was installed at your host.

$ cd esp_air_iot && npm install

Devify project template is an isomorphic JavaScript app using Node.js. Please run npm install to get Node.js modules installed.

You need to export the host IP through HOST environment variable before starting the CoAP server.

$ export HOST=192.168.0.100
$ node esp8266-coap-server.js 
WoT/CoAP server is listening at coap://192.168.0.100:8000

The message shows that the server is listening at coap://192.168.0.100:8000.

The simplest way to send sensor data to IoT server via CoAP is using NodeMCU and Lua programming language.

-- Configure the ESP as a station (client)
wifi.setmode(wifi.STATION)  
wifi.sta.config("<SSID>", "<PASSWORD>")  
wifi.sta.autoconnect(1)

-- Create a CoAP client
cc = coap.Client()

-- Make a POST request
uri="coap://192.168.0.100:8000/object/12345678/send"

-- Setup a timer to send ADC data
tmr.alarm(0, 1000, 1, function() 
    buf = 
          "{" ..
          "\"quality\":" ..
          adc.read(0) ..
          "}"
    
    cc:post(uri, buf)
    print(buf)
end)

For IoT developers, Devify is a software framework which makes it easy to build IoT server using CoAP and WebSocket. It minimizes the time to write a Hello, World IoT server. The following explains how esp8266-coap-server.js works.

First, it requires ./libs/coap-broker to get a CoAP server instance.

var server = require('./libs/coap-broker');

Then, it invokes start() method to start the server.

server.start();

The esp8266-coap-server.js demo doesn't print any thing on the screen. To print data received from NodeMCU at the terminal console, you need to modify esp8266-coap-server.js.

To print the data sent from NodeMCU, give a onmessage function callback to start().

var onmessage = function(message) {
	// Parse strings to JSON object.
	var obj = JSON.parse(message.data);
	// Print strings.
	console.log('<DATA> ' + message.data);
};

server.start({
	onmessage: onmessage,
});

Once there is an incoming message from NodeMCU, the onmessage function will be called with one parameter of Object type. The data is stored at data property of the object.

Please add the above code to your esp8266-coap-server.js file, and get it restarted.

This demo is simple. However, it's not the best practice to get data from NodeMCU.

The best practice to achieve the purpose of getting data from NodeMCU is to use coap://192.168.0.100:8000/object/12345678/viewer.

Devify framework will automatically generate this URI for your NodeMCU device. The URI is the resource name of NodeMCU data.

Write Node.js code to read the resource of this URI coap://192.168.0.100:8000/object/12345678/viewer is easy.

var coap = require('coap');

var clientWriable = coap.request('coap://192.168.0.100:8000/object/12345678/viewer');

clientWriable.on('response', function(res) {
    res.pipe(process.stdout)
});

clientWriable.end();

Please save the code under your project folder (esp_air_iot/ at this tutorial) as the file name coap-view-data.js. Then, execute coap-view-data.js by running node coap-view-data.js.

Devify has a simplified design of WoT framework.

• Take advantage of broker pattern architecture
• Thing modeling (thing description in JSON)
• URI based communications (supoprt CoAP/WebSocket)

The URI style is as the following.

coap://127.0.0.1:8000/object/<ObjectID>/send

• object is the resource name
• <ObjectID> is the unique ID of the resource. Please assign a string for your device.
• send or viewer is the property of this resource. Use send to send data to CoAP server, and viewer to view data from CoAP server

This URI style is defined in the underlying of Devify framework.

NOTE: This is under development, and which is planned to be first released on June, 2016. Please refer to devify-graph project later for flow-based IoT programming.

The above sections explain two different programming models. One is the monolithic application (aka single process) with conventional if..else... programming model. The other is the concept of resource-oriented using URI model.

However, both of these two programming models are not the vision of Devify project. The vision A new way to write IoT application server code is implemented by so-called flow-based programming (FBP).

A simple project of single process application (the monolithic application) and IF-ELSE programming model.

• How to Send SMS: The single process model

Before start to use devify-server and continue to develop your own. You can have the first experience of devify-server by deploying this basic devify-server boilerplate to Azure.

• Please click above button for one click to azure. Be sure to Enable Web Sockets after deploying your Devify web site

• Go to the Windows Azure Management Console

• Select App Services

• Select your web site, and go to the All settings page

• Scroll down and select Application settings in the GENERAL label

• Scroll down and switch the button of Web sockets to On

• Click the Save icon

• Use your web site URL to access Devify server.

• Go to the Windows Azure Management Console

• Select App Services

• Select your web site

• Find URL here, for example devify-server88de.azurewebsites.net

• Use WebSocket broker server.

• Open test/test.websocket.send.js file

• Modify this line: client.connect('ws://localhost:8000/object/5550937980d51931b3000009/send', ''); to meet your web site URL. For the example above client.connect('ws://devify-server88de.azurewebsites.net/object/5550937980d51931b3000009/send', '');

• The Devify framework will generate a URI for sending the received messages, use ws://devify-server88de.azurewebsites.net/object/5550937980d51931b3000009/viewer to received real-time messages from the server.

• The 5550937980d51931b3000009 is the device ID. You can modify it and give your favor string.

Devify is still under development. This project needs your help and contribution.

devify-server is released under the MIT License.