Basic login an authorize in backend

USEntryCoach.Server/Services/TokenService.cs

@@ -0,0 +1,56 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+using Microsoft.IdentityModel.Tokens;
+using USEntryCoach.Server.Data;
+
+namespace USEntryCoach.Server.Services;
+
+public class TokenService
+{
+    private byte[] _secretToken;
+    private double _jwtExpiryMinutes;
+    private const double DefaultJwtExpiryMinutes = 15;
+
+    public TokenService(IConfiguration configuration)
+    {
+        string? secretToken = configuration.GetValue<string>("Authentication:Secret");
+
+        if (secretToken == null)
+        {
+            throw new Exception("No Authentication Secret Token set! Please define a value for \"Authentication:SecretToken\" in appsettings.json.");
+        }
+
+        _secretToken = Encoding.ASCII.GetBytes(secretToken);
+
+        double? jwtExpiryMinutes = configuration.GetValue<double?>("Authentication:JwtExpiryMinutes");
+
+        if (jwtExpiryMinutes == null)
+        {
+            // TODO: Use logger
+            Console.WriteLine($"Warning: No expiry time for jwt session tokens defined. Using {DefaultJwtExpiryMinutes} minutes.");
+        }
+
+        _jwtExpiryMinutes = jwtExpiryMinutes ?? DefaultJwtExpiryMinutes;
+    }
+
+    public string GenerateToken(User user)
+    {
+        JwtSecurityTokenHandler tokenHandler = new();
+
+        SecurityTokenDescriptor tokenDescriptor = new()
+        {
+            Subject = new ClaimsIdentity([
+                new Claim(ClaimTypes.Name, user.Username),
+                //new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
+                new Claim(ClaimTypes.Role, user.Role.ToString())
+            ]),
+            Expires = DateTime.UtcNow.AddMinutes(_jwtExpiryMinutes),
+            SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(_secretToken), SecurityAlgorithms.HmacSha256Signature)
+        };
+
+        SecurityToken token = tokenHandler.CreateToken(tokenDescriptor);
+
+        return tokenHandler.WriteToken(token);
+    }
+}