How do I set up JWT authentication in ASP.NET Core?

How do I set up JWT authentication in ASP.NET Core?

To set up JWT authentication in ASP.NET Core, you need to configure the authentication services in the Startup.cs file.

What packages do I need to install for JWT?

You need to install the Microsoft.AspNetCore.Authentication.JwtBearer package.

Can you show me a code example for the configuration?

Sure! In your ConfigureServices method, add:

services.AddAuthentication(options => {
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options => {
    options.TokenValidationParameters = new TokenValidationParameters {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true,
        ValidIssuer = "yourIssuer",
        ValidAudience = "yourAudience",
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("yourSecretKey"))
    };
});

How do I generate a JWT token?

You can generate a JWT token using the JwtSecurityTokenHandler class. Here's a simple example:

var tokenHandler = new JwtSecurityTokenHandler();
var tokenDescriptor = new SecurityTokenDescriptor {
    Subject = new ClaimsIdentity(new Claim[] {
        new Claim(ClaimTypes.Name, userName)
    }),
    Expires = DateTime.UtcNow.AddHours(1),
    SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(Encoding.UTF8.GetBytes("yourSecretKey")), SecurityAlgorithms.HmacSha256Signature)
};
var token = tokenHandler.CreateToken(tokenDescriptor);
return tokenHandler.WriteToken(token);