C#

This is a walkthrough showing you how to connect Live Link 365's SMS-sending API to a flight booking app. This sample creates the model of a flight's booking information and sends an SMS notification to a phone number.

This is not a production-ready application. Please take your time to enhance it for production so that it meets your specific business requirements.

Steps

Pre-Requisites: For this project, external NuGet Packages are required (they are already included within the project):

  • Newtonsoft.Json: for JSON object handling
  • RestSharp: to send the requests to the API
You are free to use whatever method you feel will accomplish these functions within your own project

  1. Create the class for Flight details using id, from, to, departureTime, arriveTime, numberofSeats, availableSeats and messageHandler:
    • id: String
    • from: String
    • to: String
    • departureTime: String
    • arriveTime: String
    • numberofSeats: Integer
    • availableSeats: Integer
    • messageHandler: MessageHandler. Create a reference to the MessageHandler class to send the SMS
  2. Create the getter/setter methods to access the attributes of the Flight class.
  3. Add getAvailableSeatsAndAssign() function to return available seats with FlightID using numberofSeats and availableSeats variables, books the flight using bookFlight() function
  4. Add bookFlight() function to book a seat on the desired flight, receives the customer info and sends a message to notify the user that the booking was completed
  5. Add checkIfFlightIsDelayed() function, it receives a time and a customer's information, checks if the time is different and sends a message to the customer in case flight is delayed

Before you can use the API for sending SMS, we need to provide the basic configuration variables:

  • App Key
  • App Secret
  • Default Origin (number to be used to send the messages)
  • Proxy (optional)
See this site's Authentication section for more information

Define the class for Customer details using userName, firstName, lastName and phoneNumber:

  • userName: String
  • firstName: String
  • lastName: String
  • phoneNumber: String
Create the getter/setter methods to access the attributes of the Customer class

The flights.json file acts as a temporary storage for the flights information.

The JSON file can be replaced by a database, which holds the Flight and Customer information

MessageHandler works as a container for the functionalities required to send SMS through the API. For this step we have created two methods:

  • GetAccessToken(): This method will take the app key and secret and combine them into a Base64 string, which will then be sent to the /api/oauth/token endpoint to generate and return the authentication token
  • sendMessage(): This method makes the POST request to the API to send the SMS; it receives a message to be sent, a recipient number, and optionally we can define a number from which we want to send the message

Execute the main program. Create a Customer and read the flights file, book a seat for the customer, and finally check if the flight is delayed to notify the customer

Code

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using System;
using System.Net;
using System.Text;

// _Step_1
using Newtonsoft.Json;
using RestSharp;

namespace flightBooking.Class
{

    public class MessageHandler
    {

        private String baseUrl = "http://livelink.sapdigitalinterconnect.com/api";
        private String appKey;
        private String appSecret;
        private String defaultOrigin;
        private WebProxy globalProxy;

        public MessageHandler()
        {
        }

        public MessageHandler(String appKey, String appSecret, String defaultOrigin = "", WebProxy proxy = null)
        {
            this.appKey = appKey;
            this.appSecret = appSecret;
            this.defaultOrigin = defaultOrigin;
            this.globalProxy = proxy;
        }

        // _Step_6
        public String GetAccessToken()
        {
            String oAuthUrl = this.baseUrl + "/oauth/token";
            String bearer = Convert.ToBase64String(Encoding.UTF8.GetBytes(this.appKey + ":" + this.appSecret));
            RestClient client = new RestClient(oAuthUrl);
            if (this.globalProxy != null) {
                client.Proxy = this.globalProxy;
                client.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;
            }
            RestRequest request = new RestRequest(Method.POST);
            request.AddHeader("content-type", "application/x-www-form-urlencoded");
            request.AddHeader("authorization", "Basic " + bearer);
            request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials", ParameterType.RequestBody);

            IRestResponse<oAuthToken> response = client.Execute<oAuthToken>(request);

            if (response.StatusCode != HttpStatusCode.OK) {
                Console.WriteLine("..... Error: " + response.StatusDescription);
                return "";
            }

            String accessToken = response.Data.access_token;
            return accessToken;
        }

        public void sendMessage(String message, String destination, String origin = "") //Phone numbers have to be in E.164 format.
        {
            String messageUrl = this.baseUrl + "/v2/sms";
            Object messagePayload = new {
                message = message,
                origin =  origin == "" ? this.defaultOrigin : origin,
                destination = destination
            };
            String messageData = JsonConvert.SerializeObject(messagePayload);
            String bearer = GetAccessToken();
            if (String.IsNullOrEmpty(bearer)) {
                return;
            }
            RestClient client = new RestClient(messageUrl);
            if (this.globalProxy != null) {
                client.Proxy = this.globalProxy;
                client.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;
            }

            RestRequest request = new RestRequest(Method.POST);
            request.AddHeader("authorization", "Bearer " + bearer);
            request.AddHeader("content-type", "application/json");
            request.AddParameter("application/json", messageData, ParameterType.RequestBody);

            IRestResponse response = client.Execute(request);

            if (response.StatusCode != HttpStatusCode.OK) {
                Console.WriteLine("..... failed to send message.");
                Console.WriteLine("..... Error: " + response.ErrorMessage);
            }
        }
    }
}

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using System;
namespace flightBooking.Class
{

    // _Step_2
    public class Flight
    {

        private String id;
        private String from;
        private String to;
        private String departureTime;
        private String arriveTime;
        private Int32 numberOfSeats;
        private Int32 availableSeats;

        // _Step_3
        private MessageHandler messageHandler = new MessageHandler("", "", "");// Insert here your appkey, appSecret and default origin respectively.

        public String Id { get => id; set => id = value; }
        public String From { get => from; set => from = value; }
        public String To { get => to; set => to = value; }
        public String DepartureTime { get => departureTime; set => departureTime = value; }
        public String ArriveTime { get => arriveTime; set => arriveTime = value; }
        public Int32 NumberOfSeats { get => numberOfSeats; set => numberOfSeats = value; }
        public Int32 AvailableSeats { get => availableSeats; set => availableSeats = value; }



        public Flight()
        {
        }

        public Flight(String id, String from, String to, String departureTime, String arriveTime, Int32 numberOfSeats = 10)
        {
            this.id = id;
            this.from = from;
            this.to = to;
            this.departureTime = departureTime;
            this.arriveTime = arriveTime;
            this.numberOfSeats = numberOfSeats;
            this.availableSeats = numberOfSeats;
        }

        public String getAvailableSeatsAndAssign(Int32 numberOfSeatsToBook)
        {
            if (numberOfSeatsToBook > this.availableSeats) {
                return "Seats amount to book is higher than the seats avalaible for flight " + this.id;
            }
            this.availableSeats -= numberOfSeatsToBook;
            return this.id + "-" + this.availableSeats;

        }

        public void bookFlight(Customer customer)
        {
            String message = "Hi " + customer.FirstName + " your flight has been booked with seat number " + getAvailableSeatsAndAssign(1) +
                                             ", from: " + this.from + ", to: " + this.to + ", departuring at " + this.departureTime;
            messageHandler.sendMessage(message, customer.PhoneNumber);
        }

        public void checkIfFlightIsDelayed(String newDepartureTime, Customer customer)
        {
            if (this.DepartureTime != newDepartureTime) {
                String message = "Flight " + this.id + " from: " + this.from + " to: " + this.to + " is delayed, the new departure time will be at " + newDepartureTime;
                messageHandler.sendMessage(message, customer.PhoneNumber);
            }
        }
    }
}

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using System;
namespace flightBooking.Class
{

    // _Step_4
    public class Flight
    {

        private String id;
        private String from;
        private String to;
        private String departureTime;
        private String arriveTime;
        private Int32 numberOfSeats;
        private Int32 availableSeats;
        private MessageHandler messageHandler = new MessageHandler("", "", "");// Insert here your appkey, appSecret and default origin respectively

        public String Id { get => id; set => id = value; }
        public String From { get => from; set => from = value; }
        public String To { get => to; set => to = value; }
        public String DepartureTime { get => departureTime; set => departureTime = value; }
        public String ArriveTime { get => arriveTime; set => arriveTime = value; }
        public Int32 NumberOfSeats { get => numberOfSeats; set => numberOfSeats = value; }
        public Int32 AvailableSeats { get => availableSeats; set => availableSeats = value; }



        public Flight()
        {
        }

        public Flight(String id, String from, String to, String departureTime, String arriveTime, Int32 numberOfSeats = 10)
        {
            this.id = id;
            this.from = from;
            this.to = to;
            this.departureTime = departureTime;
            this.arriveTime = arriveTime;
            this.numberOfSeats = numberOfSeats;
            this.availableSeats = numberOfSeats;
        }

        public String getAvailableSeatsAndAssign(Int32 numberOfSeatsToBook)
        {
            if (numberOfSeatsToBook > this.availableSeats) {
                return "Seats amount to book is higher than the seats avalaible for flight " + this.id;
            }
            this.availableSeats -= numberOfSeatsToBook;
            return this.id + "-" + this.availableSeats;

        }

        public void bookFlight(Customer customer)
        {
            String message = "Hi " + customer.FirstName + " your flight has been booked with seat number " + getAvailableSeatsAndAssign(1) +
                                             ", from: " + this.from + ", to: " + this.to + ", departuring at " + this.departureTime;
            messageHandler.sendMessage(message, customer.PhoneNumber);
        }

        public void checkIfFlightIsDelayed(String newDepartureTime, Customer customer)
        {
            if (this.DepartureTime != newDepartureTime) {
                String message = "Flight " + this.id + " from: " + this.from + " to: " + this.to + " is delayed, the new departure time will be at " + newDepartureTime;
                messageHandler.sendMessage(message, customer.PhoneNumber);
            }
        }
    }
}

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// _Step_5
[
    {
        "id": "UNI101",
        "from": "New York",
        "to": "Chicago",
        "departureTime": "11:30AM",
        "arriveTime": "01:00PM",
        "numberOfSeats": 50,
        "availableSeats": 3
    },
    {
        "id": "AUX201",
        "from": "Boston",
        "to": "Miami",
        "departureTime": "11:10AM",
        "arriveTime": "02:00PM",
        "numberOfSeats": 12,
        "availableSeats": 8
    }
]

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using System;
using Newtonsoft.Json;
using System.IO;
using System.Collections.Generic;
using flightBooking.Class;

namespace flightBooking
{
    class MainClass
    {
        // _Step_7
        public static void Main(string[] args)
        {
            List<Flight> flights;
            Customer customer = new Customer("SAMS", "Sam", "Smith", "+132948392423");//Create a customer, asign an id, first name, last name and the phone number to send the message
            using (StreamReader info = File.OpenText(@"../../Resources/flights.json")) { //Retrieve the flight information
                JsonSerializer serializer = new JsonSerializer();
                flights = (List<Flight>)serializer.Deserialize(info, typeof(List<Flight>));
            }

            flights[0].bookFlight(customer);//Book a seat for the customer
            flights[1].checkIfFlightIsDelayed("11:50AM", customer);//Check if customer flight is delayed
        }
    }
}