Telma USSD from HTTP

Author: balzacLeGeek

config/account.js

@@ -0,0 +1,4 @@
+// (4 int) pwd : Your Mvola Password
+module.exports = {
+	pwd : 'not_set'
+}

config/modem.js

@@ -0,0 +1,10 @@
+/*
+	(string) com: 'COMx' (Windows), '/dev/ttyUSBx' (Linux)
+	(array) options: { read_time : 'Max timeout for wait AT Command response' }
+*/
+module.exports = {
+	com : 'COM3',
+	option: {
+		read_time: 10000,
+	}
+}

index.js

@@ -8,9 +8,13 @@ var cors = require('cors');
 // Config
 var server_config = require('./config/server');
 
+// API Routes
+var ussd_api = require('./routes/ussd');
+
 var app = express();
 
 app.use(cors());
+app.use('/api/ussd', ussd_api);
 
 var server = require('http').Server(app);
 

libs/ModemLib.js

@@ -0,0 +1,89 @@
+'use strict'
+
+var Port = require('serial-at');
+var modem_config = require('../config/modem');
+var account_config = require('../config/account');
+
+const port = new Port(modem_config.com, modem_config.option);
+var ussd_code = "";
+var need_mvola_pwd = false;
+
+const ModemLib = function() {
+
+	const executeUSSD = function(ussd_type, callback) {
+
+		if (ussd_type == 'mvola_balance') {
+			need_mvola_pwd = true;
+			ussd_code = '"#111*1*6*1*' + account_config.pwd + '#"';
+		}
+		else if(ussd_type == 'account_balance') {
+			ussd_code = '"#357#"';
+		}
+		else if(ussd_type == 'forfait_balance') {
+			ussd_code = '"#358#"';
+		}
+
+		if (need_mvola_pwd && checkMvolPwd(account_config.pwd) == false) {
+			console.log("Mvola Password not set");
+			return callback({ 'status': 401, 'error': { 'message': 'Please set your Mvola password' } });
+		}
+
+		port.open()
+		    .then(result => {
+		        console.log("Executing AT Command");
+
+		        port.at('AT+CUSD=1, ' + ussd_code + ', 15')
+		            .then(result => {
+		            	var result	= ModemLib.hexToString(result.split(',')[1].replace(/^"|"$/g, ''));
+		                let payload = {
+							status: 200,
+							success: {
+								message: result
+							}
+						}
+
+						console.log(result);
+						return callback(null, payload);
+		            })
+		            .catch(err => {
+		            	let payload = {
+							status: 500,
+							error: {
+								message: "An error has occured when excuting USSD Command. Please try later"
+							}
+						}
+		            	
+		            	console.log(`.catch(${err})`);
+						return callback(payload);
+		            });
+		    })
+		    .catch(err => {
+
+		    	let payload = {
+					status: 302,
+					error: {
+						message: 'Service permanently unnavaible. Please try later'						
+					}
+				}
+		    	
+		    	console.log(`.catch(${err})`);
+				return callback(payload);
+		    });
+	}
+
+	const hexToString = function(hex) {
+		return Buffer.from(hex, 'hex').toString('utf8');
+	}
+
+	const checkMvolPwd = function(pwd) {
+		if (pwd == 'not_set')
+			return false;
+	}
+
+	return {
+		executeUSSD: executeUSSD,
+		hexToString: hexToString,
+	}
+}()
+
+module.exports = ModemLib