Using Windows Authentication on Intranet app, can we get current user name at startup, available then for any CRUD service?

[Antony]

Currently I have nine service classes in this, my first Blazor app (.Net 6). Each service contains the usual async Tasks required for CRUD, eg GetStudyFees, CreateStudyFee, UpdateStudyFee. So, since this is a data intensive intranet app, which is I believe considered just the thing Blazor Server is good for, in each service I need a connection string ( I'm using Dapper), and I need the current user name, since we want to save CreatedBy and ModifiedBy.

This is how I've set this up for one service:

        
private readonly string _conn;
        private readonly AuthenticationStateProvider _auth;

        public StudyFeeService(IConfiguration config, AuthenticationStateProvider auth)
        {
            _conn = config.GetConnectionString("PharmCTConn");
            _auth = auth;
        }

        public async Task<string> GetUser()
        {
            var authState = await _auth.GetAuthenticationStateAsync();
            var user = authState.User;
            return user.Identity.Name;
        }
        public async Task<bool> CreateStudyFee(StudyFeeViewModel studyFee)
        {
            var parameters = new DynamicParameters();
            studyFee.CreatedBy = await GetUser();

            parameters.AddDynamicParams(new
            {
                studyFee.HREC,
                studyFee.Fee,
                studyFee.CreatedBy
            });  

            using (var conn = new SqlConnection(_conn))
            {
                string query = @"insert into dbo.StudyFee (HREC, Fee, CreatedBy) 
                                 values (@HREC, @Fee, @CreatedBy)";

                await conn.ExecuteAsync(query, parameters, commandType: CommandType.Text);
            }
            return true;
        }

I could duplicate this code at the top of each of my service classes, but instead is there a way that the GetUser Task could be run in Program.cs perhaps, making the username then available by injection for all services to access? I have read quite a bit around this, including StackOverflow, but being inexperienced both with Blazor and .Net Core, I haven't been able to work it out. The app will only open once the user has logged in using Windows Authentication - there is no anonymous user.

[Antony]

Actually, yes, I'm repeating that GetUser() method in each service, but it's simple and short - and often the alternative is not so simple and short - so I'm happy. But if you do know a neat and elegant alternative, it might be useful to a lot of people.

[Deasun]

Might be reading wrong, but cant you build a global class to keep the userid in.

Just fill that in with your userId from getuser() in the index page.

Then on the others read from the Globalstuff.userid ?