Configuration Validator

A small side project for validating the items loaded into your .NET Core application's global configuration.

Currently supported validation rules:

• required: Checks to see if the value for a specific key is set, and is not null.
  • Valid values: true, false

Future planned rules:

• format: Checks to see if the value matches a specific format, such as an int, bool, or base64/byte[] type
• regex: Checks to see if the value matches some supplied regex mask
• maxlength: Checks to see that the string for this value does not exceed some specified length
• minlength: Checks to see that the string for this value is not smaller than some specified length
• minbytes: Checks to see the value is at least a minimum length of bytes (requires base64 format check)
• matches: Checks to see the value matches one of a specified list of values
• uniquepassword: Checks to see the value is not on a known list of compromised passwords (requires outbound internet connection to talk to https://haveibeenpwned.com/Passwords)
  • This will throw a warning but not an exception, since this will leak the presence of secrets if a new password is added to Pwned Passwords that is used by the application. It is up to the developer to rectify this.

How do I get this in my awesome project?

Add the InFurSecDen.Utils.ConfigutationValidator NuGet package using the usual NuGet methods:

Powershell:

Install-Package InFurSecDen.Utils.ConfigutationValidator -IncludePrerelease

dotnet CLI:

dotnet add package InFurSecDen.Utils.ConfigurationValidator -prerelease

.csproj:

<PackageReference Include="InFurSecDen.Utils.ConfigutationValidator" Version="x.x.x"/>

How do I use it?

configurationschema.json

Create a file (usually configurationschema.json) in the following format:

{
	"Key1": {
		"required": true
	},
	"Key2:SubKey1": {
		"required": true
	},
	"Key2:SubKey2": {
		"required": true
	}
}

Configuration Builder

In your IConfigurationBuilder builder methods (usually in Program.cs as of ASP.NET Core 2.1), after all of the configuration sources are defined, add the following line (assuming config is the name of your IConfigurationBuilder object):

var errors = config.Validate(File.ReadAllText("configurationschema.json"));

If errors.Count returns zero, the schema was successfully validated.

Optionally, you can throw an AggregateException with the following line:

config.Validate(File.ReadAllText("configurationschema.json"), throwOnError: true);

All this talk about NuGet is making me hungry for chicken nuggets! 🦊

Me too. If you're based in New Zealand, I recommend the BP Connect chicken nuggets, they're by far the biggest and have the tastiest seasonings. No, seriously.

Don't go to K-Fry. I don't know how but they somehow manage to totally fuck up cooking chicken, and this offends me mightily.