How to validate this configuration value?

Question

I have a .net 8 web application. In the Program.cs I have the following code:

var applicationName = builder.Configuration.GetValue<string>("DataProtection:ApplicationName");
builder.Services.AddDataProtection().SetApplicationName(applicationName);

How can this code be re-written so applicationName becomes validated in a correct way. The only rule is that it should not be null or empty.

I have seen that .net 8 has some new stuff for validating options and configurations. How could that be applied in this scenario?

Answer 1

You can use ValidateDataAnnotations documentation

Example define poco as you needed

public class DataProtectionOptions
{
    [Required(ErrorMessage = "The ApplicationName for data protection is required.")]
    public string ApplicationName { get; set; }
}

Bind and validate configuration

builder.Services.AddOptions<DataProtectionOptions>()
    .Bind(builder.Configuration.GetSection("DataProtection"))
    .ValidateDataAnnotations();