Kony Fabric console User Guide: APIs in API Management > How Node.js works in MobileFabric

Logic - API Management

The logic services feature in Kony Fabric helps you import and integrate Node.js services (APIs) directly into Kony Fabric for developing server-side and networking applications. You can now enhance the capability of your Kony Fabric applications by adding custom services that are created within Node.js packages/projects. Node.js is an open-source and cross-platform runtime environment. Node.js applications are written in JavaScript, and can be run within the Node.js runtime on Mac OS, Microsoft Windows, and Linux. Node.js also provides a rich library of JavaScript modules that simplify the development of web applications using Node.js. Currently, Kony Fabric supports Node.js V6.2.2 or above.

Node.js Package Structure

A Node.js package contains the following folders and files.

Swagger.json:

The Swagger.json file includes all paths for services / APIs of the Node.js package.
The host key should be present and hostname should be localhost and port value must be within 9000 - 10000.
The basePath key should be present and value should with /services/ and followed by user app base path.
The mfidentitylevel, which is optional, is used to enable auth protection for the resources. Possible values are: public, protected, and anonymous.

The following is a sample code for swagger.json.

 {
  "info": {
    "title": "Kony Fabric Logic (Node.js) sample application for managing Contacts",
    "version": "1.0.0",
    "description": "This sample application demonstrates use of Logic (Node.js) app in Kony Fabric"
  },
  "host": "localhost:9000", "basePath": "/services/mailapp",
  "swagger": "2.0",
  "paths": {
    "/api/v1/contact": {
      "post": {
        "tags": [
          "Contacts"
        ],
        "description": "Contact Details object",
        "produces": [
          "application/json"
        ],
        "parameters": [
          {
            "name": "Details",
            "description": "Contact Details",
            "in": "body",
            "required": true,
            "schema": {
              "$ref": "#/definitions/Contact Details"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Successfully created"
          }
        },
        "mfidentitylevel": "public"
      }
    }
  },
  "definitions": {
    "Contact Details": {
      "properties": {
        "firstName": {
          "type": "string"
        },
        "lastName": {
          "type": "string"
        },
        "rollNumber": {
          "type": "string"
        },
        "mobileNumber": {
          "type": "string"
        }
      }
    }
  },
  "responses": {},
  "parameters": {},
  "securityDefinitions": {},
  "tags": []
}

Package.json:

The Package.json file contains Node.js module dependencies.
The script start key must be present. Kony Fabric logic services uses the start key to start the user app. The following is a sample code for package.json.

 {
  "name": "Sample_USERAPP",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "dependencies": {
    "body-parser": "~1.15.1",
    "cookie-parser": "~1.4.3",
    "debug": "~2.2.0",
    "express": "~4.13.4",
    "hjs": "~0.0.6",
    "less-middleware": "1.0.x",
    "mfgateway": "^1.0.0",
    "morgan": "~1.7.0",
    "serve-favicon": "~2.3.0",
    "swagger-jsdoc": "^1.3.0"
  }
}

Sample Node.js Package Structure

User app: A user app is built on express JS. The following is a sample folder structure of a user app (Node.js package).

 Sample_USERAPP
├───bin
     |_www
│
├───public
├───routes
      |_ contact.js (Add your routes by adding new JS file here if you are using Kony Fabric sample app)
│
├───views
├───app.js
├───package.json
├───swagger.json

How Node.js Works in Kony Fabric

Once you build a node.js package (in a .zip file), you need to import the package file into Kony Fabric Console.
Publish the Node.js package into the Node.js runtime server through the console.
Node.js services published from the package are available in the Kony Fabric Console > Apps > Configure Services > Logic tab.
You can then integrate/associate services created in Node.js packages to Kony Fabric applications.
Finally, the app needs to be published by selecting a Node.js environment.

Important: Ensure that your package details (files and folders) are zipped in the root of the .zip file.

Benefits of Node.js App Development

The logic services feature offers the following advantages for quickly mobilizing Node.js services in Kony Fabric for building apps:

Logic services exposes services created in Node.js helps you use custom Node.js services for building mobile apps.
Integrate custom services (APIs) created in Node.js language directly into Kony Fabric apps, and develop server-side and networking applications.
Protect Node.js services (APIs) by setting security levels that control Kony Fabric Identity services for authentication of apps users.
Build scalable network applications using Node.js technology in Kony Fabric apps.
Node.js supports a non-blocking input/output model that makes it lightweight and efficient.

Use Cases

For creating real-time web apps: Node.js technology improves the performance and development of web apps.
For creating Web sites: Node.js technology helps you share code between the browser and the back end.

Limitations

Read the following limitations for Node.js services before associating the services with Kony Fabric apps.

Currently, one Node.js package for one user is allowed.
Logic services tab support is available only for Kony Cloud.

Prerequisites

Always use the npm install save option to install any modules.
For example, to add the package in dependencies, follow the commands:
```
 npm install --save my_dep
```
or
```
 npm install -S my_dep
```
The above commands ensure that all the dependencies are updated to package.json file.
Ensure that your package details (files and folders) are zipped in the root of the .zip file.
Ensure the port specified in swagger.json range starts from 9000 to 10000.
Ensure that the port in swagger.json should match with the one specified in the application code.

Avoid the npm_modules folder in the final .zip file, which you want to upload to Kony Fabric. The npm_module folder increases unnecessary package file size.
Important: The user app should not depend on PORT environment variable. By default, if you are using express-generator to generate an express basic project, the bin/www folder will have a PORT environment variable to refer to port value. In the bin/www folder, use port number directly.

For example,
```
 var port = normalizePort(process.env.PORT || '3000');
```
will become

var port = normalizePort('9000');

Logging Service Support for User App

The following sample code is to enable logging in the user apps. Using the mflogger, the user app logs can also be captured.

 let mflogger;

// Kony logger to capture application logs to display using logging service
try {
// The following require statement imports the admin app's logging service into the user app through which user can capture logs.
mflogger = require(process.env.KONY_LOGIC_LOGGER);
} catch(e) {
// If the above statement fails, all the user app logs are captured in the default console output.
mflogger = console;
}

Use the mflogger instance for logging in the user app. Supported logging methods: debug, info, warn, and error.

 mflogger.info('Message to log ...');

Troubleshooting

Unauthorized: If you see the following message indicates that your endpoint resource is protected by Kony Fabric identity services configured for your application. So you need to generate Kony Fabric login token and provide it as part of header with name as X-Kony-Authorization

 {
    "message": "Authentication failed"
}

Error: If you see the following error, unpublish the user package from the API Management > Logic tab, and re-publish it.

 {
    "error": "Connection error."
}

For technical questions, suggestions, and comments, or to report problems on Kony's product line, contact support@kony.com.

Node.js Services Integration in Kony Fabric

Node.js services integration in Kony Fabric apps involves the following two steps:

How to Publish Node.js Package into Node.js Runtime Server in API Management. This section details how to import a Node.js package into Kony Fabric Console and publish the package to the Node.js Runtime Server.
How to Integrate Node.js Services into Kony Fabric Apps. This section details how to integrate Node.js services to Kony Fabric apps.

Rev	Author	Edits
7.2	SD	SD