Gets users and group based role assignment

UserAndGroupRoles.cs

// Get user role assignments
var oid = context.Principal.FindFirstValue("http://schemas.microsoft.com/identity/claims/objectidentifier");
var userRoles = dbContext.RoleMaps.Where(w => w.ObjectId == oid).Join(dbContext.Roles, map => map.RoleId,
    role => role.Id, (map, role) => new {RoleName = role.Name}).ToList();
    
// Get group role assignments
var groupClaims = context.Principal.Claims.Where(w => w.Type == "groups").Select(s => s.Value).ToList();
var groupRoles = dbContext.RoleMaps.Where(w => groupClaims.Contains(w.ObjectId)).Join(dbContext.Roles, map => map.RoleId,
  role => role.Id, (map, role) => new { RoleName = role.Name }).ToList();
  
// Merge lists
var roleData = userRoles.Concat(groupRoles).ToList();

// Assign roles to claims, loop for multiple roles
if (roleData.Count != 0)
{
    List<Claim> claims = new List<Claim>();
    foreach (var role in roleData)
    {
        claims.Add(new Claim(ClaimTypes.Role, role.RoleName));
    }

    // Assign claim to the identity object
    var appRoles = new ClaimsIdentity(claims);
    context.Principal.AddIdentity(appRoles);
}