feat: helper functions for checking roles and a demo endpoint

Controllers/GeneralUseHelperFunctions.cs

@@ -14,6 +14,78 @@ public class GeneralUseHelpers(ApplicationDbContext db, IConfiguration appsettin
     private readonly ApplicationDbContext _db          = db;
     private readonly IConfiguration       _appsettings = appsettings;
 
+    // Allows to check whether the user is of role present in roles.
+    // Example:
+    // For user with role 0,
+    // - IsUser(["Manager"],          req) yields false
+    // - IsUser(["Admin"],            req) yields true
+    // - IsUser(["Admin", "Manager"], req) yields true because the user is an admin
+    public bool IsUser(string[] roles, HttpRequest req)
+    {
+
+        // Get the user to read its roles
+        User? user = GetUserFromToken(req.Headers.Authorization!);
+        if (user == null) {
+            return false;
+        }
+        foreach (var role in roles)
+        {
+            if (string.IsNullOrEmpty(role))
+            {
+                continue;
+            }
+            switch (role)
+            {
+                case "Admin":
+                    if (user.Role == 0)
+                        return true;
+                    break;
+                case "Manager":
+                    if (user.Role == 1)
+                        return true;
+                    break;
+                case "Pracownik":
+                    if (user.Role == 2)
+                        return true;
+                    break;
+                default:
+                    continue;
+            }
+        }
+
+        return false;
+    }
+
+    public string UserRoleAsStr(User user)
+    {
+        switch (user.Role)
+        {
+            case 0:
+                return "Admin";
+            case 1:
+                return "Manager";
+            case 2:
+                return "Pracownik";
+            default:
+                return "Unknown role";
+        }
+    }
+
+    public User? GetUserFromToken(string token)
+    {
+        if (token.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase))
+        {
+            token = token.Substring("Bearer ".Length).Trim();
+        }
+        var handler = new JwtSecurityTokenHandler();
+        var jwtSecurityToken = handler.ReadJwtToken(token);
+        if (int.TryParse(jwtSecurityToken.Subject, out int userId))
+        {
+            return _db.Users.FirstOrDefault(u => u.Id == userId);
+        }
+        return null;
+    }
+
     async public Task<User?> GetUserFromEmail(string email)
     {
         return await _db.Users.FirstOrDefaultAsync(e => e.Email == email);
@@ -37,7 +109,6 @@ public class GeneralUseHelpers(ApplicationDbContext db, IConfiguration appsettin
         var claims = new[]
         {
             new Claim(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
-            // new Claim(ClaimTypes.Role, )
             new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString())
         };