complete jwt authentication with user identity in csharp

To complete JWT authentication with user identity in C#, you can follow the steps outlined below:

Install the required packages: You need to install the following packages in your C# project using the Package Manager Console:

Microsoft.AspNetCore.Authentication.JwtBearer
Microsoft.AspNetCore.Identity.EntityFrameworkCore
Microsoft.EntityFrameworkCore

Configure the JWT authentication: You can configure the JWT authentication by adding the following code to your Startup.cs file:


main.cs
services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
}).AddJwtBearer(options =>
{
    options.RequireHttpsMetadata = false;
    options.SaveToken = true;
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(Configuration.GetSection("AppSettings:Token").Value)),
        ValidateIssuer = false,
        ValidateAudience = false
    };
});
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This code configures the JWT authentication by specifying the authentication scheme as JwtBearerDefaults.AuthenticationScheme and setting the token validation parameters.

Add Identity to the project: You can add Identity to your project by creating a class that derives from IdentityUser, as shown in the code below:


main.cs
public class ApplicationUser : IdentityUser
{
}
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Configure Identity: To configure Identity, you need to add the following code to the ConfigureServices method of the Startup.cs file:


main.cs
services.AddDbContext<DataContext>(options =>
    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

services.AddDefaultIdentity<ApplicationUser>()
    .AddEntityFrameworkStores<DataContext>();
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This code configures the database context and adds the default Identity schema to the project.

Generate the JWT token: To generate the JWT token, you can use the following code in your authentication controller:


main.cs
var claims = new[]
{
    new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
    new Claim(ClaimTypes.Name, user.UserName)
};

var key = new SymmetricSecurityKey(Encoding.UTF8
    .GetBytes(_config.GetSection("AppSettings:Token").Value));

var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha512Signature);

var tokenDescriptor = new SecurityTokenDescriptor
{
    Subject = new ClaimsIdentity(claims),
    Expires = DateTime.Now.AddDays(1),
    SigningCredentials = creds
};

var tokenHandler = new JwtSecurityTokenHandler();

var token = tokenHandler.CreateToken(tokenDescriptor);

return Ok(new
{
    token = tokenHandler.WriteToken(token)
});
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