Implement basic authentication in web api c#

First, create an empty web API project . Then follow the below steps:

Here I want to validate the user if the user exists then display the employee details based on username.

1. Create a User model class and Employee model.

User Model Class	Employee Model Class
public class User     {         public int ID { get; set; }         public string UserName { get; set; }         public string Password { get; set; }     }	public class Employee     {         public int ID { get; set; }         public string Name { get; set; }         public string Gender { get; set; }         public string Dept { get; set; }         public int Salary { get; set; }     }

 

2. Creating a class that returns the list of employees and users.

User List

Employee List

public class UsersBL     {         public List GetUsers()         {                       List userList = new List();             userList.Add(new User()             {                 ID = 101,                 UserName = "MaleUser",                 Password = "123456"             });             userList.Add(new User()             {                 ID = 101,                 UserName = "FemaleUser",                 Password = "abcdef"             });             return userList;         }     }

public class EmployeeBL     {         public List GetEmployees()         {             List empList = new List();             for (int i = 0; i < 10; i++)             {                 if (i > 5)                 {                     empList.Add(new Employee()                     {                         ID = i,                         Name = "Name" + i,                         Dept = "IT",                         Salary = 1000 + i,                         Gender = "Male"                     });                 }                 else                 {                     empList.Add(new Employee()                     {                         ID = i,                         Name = "Name" + i,                         Dept = "HR",                         Salary = 1000 + i,                         Gender = "Female"                     });                 }             }             return empList;         }

 
3. Creating UserValidate class to validate the user

       public class UserValidate
        {
            //This method is used to check the user credentials
            public static bool Login(string username, string password)
            {
                UsersBL userBL = new UsersBL();
                var UserLists = userBL.GetUsers();
                return UserLists.Any(user =>
                    user.UserName.Equals(username, StringComparison.OrdinalIgnoreCase)
                    && user.Password == password);
            }
        }

4. Creating BasicAuthenticationAttribute class to implement basic authentication

      public override void OnAuthorization(HttpActionContext actionContext)
        {
            //If the Authorization header is empty or null
            //then return Unauthorized
            if (actionContext.Request.Headers.Authorization == null)
            {
                actionContext.Response = actionContext.Request
                    .CreateResponse(HttpStatusCode.Unauthorized);

                // If the request was unauthorized, add the WWW-Authenticate header
                // to the response which indicates that it require basic authentication
                if (actionContext.Response.StatusCode == HttpStatusCode.Unauthorized)
                {
                    //Code
                }
            }
            else
            {
                //Get the authentication token from the request header
                string authenticationToken = actionContext.Request.Headers
                    .Authorization.Parameter;

                //Decode the string
                string decodedAuthenticationToken = Encoding.UTF8.GetString(
                    Convert.FromBase64String(authenticationToken));

                //Convert the string into an string array
                string[] usernamePasswordArray = decodedAuthenticationToken.Split(':');

                //First element of the array is the username
                string username = usernamePasswordArray[0];

                //Second element of the array is the password
                string password = usernamePasswordArray[1];

                //call the login method to check the username and password
                if (UserValidate.Login(username, password))
                {
                    var identity = new GenericIdentity(username);

                    IPrincipal principal = new GenericPrincipal(identity, null);
                    Thread.CurrentPrincipal = principal;

                    if (HttpContext.Current != null)
                    {
                        HttpContext.Current.User = principal;
                    }
                }
                else
                {
                    actionContext.Response = actionContext.Request
                        .CreateResponse(HttpStatusCode.Unauthorized);
                }
            }
        }

5. Add the below code in webApiConfig.cs file

            config.Filters.Add(new BasicAuthenticationAttribute());

6. Finally, create a controller and add [BasicAuthentication] filter for which you want to authenticate

    [BasicAuthentication]
    public class DefaultController : ApiController
    {
 
        public HttpResponseMessage GetEmployees()
        {
            string username = Thread.CurrentPrincipal.Identity.Name;
            var EmpList = new EmployeeBL().GetEmployees();
            switch (username.ToLower())
            {
                case "maleuser":
                    return Request.CreateResponse(HttpStatusCode.OK,
                        EmpList.Where(e => e.Gender.ToLower() == "male").ToList());
                case "femaleuser":
                    return Request.CreateResponse(HttpStatusCode.OK,
                        EmpList.Where(e => e.Gender.ToLower() == "female").ToList());
                default:
                    return Request.CreateResponse(HttpStatusCode.BadRequest);
            }
        }

    }