API data validation

Scenario:

Create a Sign on service to allow creation of users in our app. Add validation for max/min length for UserName mode

Solution:

1. 
   

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[MaxLength(100, ErrorMessage = "Invalidparam*maximum length of 100*userName")]
[MinLength(10)]
public string UserName { get; set; }



2. 
   

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var errors = modelState.Where(ms => ms.Value.Errors != null && ms.Value.Errors.Count > 0)
                .SelectMany(ms => ms.Value.Errors)
                .Select(e =>
                {
                    if (e.message.Contains("*"))
                    {
                        var details = e.message.Split('*');
                        return new Error
                        {
                            Code = details[0],
                            Description = details[1],
                            Parameter = details[2]
                        };
                    }

                    return new Error
                    { Code = "InvalidRequest", Details = e.message };
                }).ToList();