Cleaning User Input

Question

I am not sure if I am approaching this task the correct way. I have a view model with multiple string properties. I pass the model through an interface to a service class that contains a void to repopulate the user input with my desired format.

using System.Globalization;
using System.Text.RegularExpressions;
using System.Threading;
using System.Web.Helpers;
public class RegisterViewModel
{
    public string UserId { get; set; }
    public string Password { get; set; }
    public string RecoveryAnswer { get; set; }
    public int? EmpId { get; set; }
    public string EId { get; set; }
    public string UId { get; set; }
    public string PeopleSafeId { get; set; }
    public string StarsId { get; set; }
    public string NamePrefix { get; set; }
    public string NameFirst { get; set; }
    public string NameMiddle { get; set; }
    public string NameLast { get; set; }
    public string NameSuffix { get; set; }
    public string Email { get; set; }
    public string PhoneNumber { get; set; }
    public string PhoneExtension { get; set; }
    public int? DepartmentId { get; set; }
    public int? TitleId { get; set; }
    public int DomainId { get; set; }
    public int? LocationId { get; set; }
}

public interface IRegisterService
{
    RegisterViewModel CleanUserInput(RegisterViewModel model);
    //...
}

public class RegisterService : IRegisterService
{
    public RegisterViewModel CleanUserInput(RegisterViewModel model)
    {
        CultureInfo cultureInfo = Thread.CurrentThread.CurrentCulture;
        TextInfo textInfo = cultureInfo.TextInfo;
        model.UserId = model.UserId.ToUpper();
        model.Password = Crypto.HashPassword(model.Password);
        model.RecoveryAnswer = Crypto.HashPassword(model.RecoveryAnswer);
        model.EId = model.EId.ToUpper();
        model.UId = model.UId.ToUpper();
        model.PeopleSafeId = model.PeopleSafeId.ToUpper();
        model.StarsId = model.StarsId.ToUpper();
        model.NamePrefix = textInfo.ToTitleCase(model.NamePrefix);
        model.NameFirst = textInfo.ToTitleCase(model.NameFirst);
        model.NameMiddle = textInfo.ToTitleCase(model.NameMiddle);
        model.NameLast = textInfo.ToTitleCase(model.NameLast);
        model.NameSuffix = textInfo.ToTitleCase(model.NameSuffix);
        model.Email = model.Email.ToLower();
        model.PhoneNumber = Regex.Replace(model.PhoneNumber, "[^0-9]", "");
        model.PhoneExtension = Regex.Replace(model.PhoneNumber, "[^0-9]", "");
        return model;
    }
    //...
}

Is there a better way to approach cleaning up this much input?

Answer 1

This seems pretty clean to me. It's very testable, which is a definite must-have. It also decouples the reformatting of user input from the view-model. Looser coupling between layers is a positive thing. The downside is that you'd need to create a service for each view model. I'm going back and forth in my head whether this approach is best, or if defining some custom class and property attributes might be more worth while, and then use the service to process any object in a generic manor by looking at the attributes associated with a view-model property.

Some pseudo code:

RegisterViewModel.cs

public class RegisterViewModel
{
    [CleanUserInput.ToUpperCase]
    public string UserId { get; set; }
    [CleanUserInput.HashValue]
    public string Password { get; set; }
    public string RecoveryAnswer { get; set; }
    public int? EmpId { get; set; }
    [CleanUserInput.ToUpperCase]
    public string EId { get; set; }
    [CleanUserInput.ToUpperCase]
    public string UId { get; set; }
    [CleanUserInput.ToUpperCase]
    public string PeopleSafeId { get; set; }
    public string StarsId { get; set; }
    public string NamePrefix { get; set; }
    public string NameFirst { get; set; }
    public string NameMiddle { get; set; }
    public string NameLast { get; set; }
    public string NameSuffix { get; set; }
    [CleanUserInput.ToLowerCase]
    public string Email { get; set; }
    [CleanUserInput.StripNonDigits]
    public string PhoneNumber { get; set; }
    public string PhoneExtension { get; set; }
    public int? DepartmentId { get; set; }
    public int? TitleId { get; set; }
    public int DomainId { get; set; }
    public int? LocationId { get; set; }
}

Then the definitions for the property attributes:

namespace CleanUserInput
{
    public class ToUpperCaseAttribute : System.Attribute
    {
        // ...
    }

    public class HasValueAttribute : System.Attribute
    {
        // ...
    }

    public class StripNonDigitsAttribute : System.Attribute
    {
        // ...
    }
}

Your service could get the System.Type object for the view model, and then inspect the Attributes using class reflection. This could make processing multiple view models easily repeatable with little additional code.