ilya.rudenka/FlatValidatorv2.6.2
.NET 8.0.NET 9.0.NET 10.0
A validation library for .NET that delivers an high-performance and memory prudence by using lambda-based and strongly-typed rules.
Get Started
$ dotnet add package FlatValidatorReadme
The FlatValidator is a validation library for .NET that delivers an high performance and memory prudence by using lambda-based and strongly-typed rules.
Quick examples
In general, there are two simple ways to validate custom data with the FlatValidator.
1. Inline mode
You can define validation rules in your code to validate object locally.
var someModel = new SomeModel(
Email: "email@email.com",
BirthDate: DateTime.Now,
Rate: -100
);
// validate synchronously
var result = FlatValidator.Validate(someModel, v =>
{
// IsEmail() is one of built-in funcs for typical data formats
// like Phone, Url, CreditCard, Password, etc.
v.ValidIf(m => m.Email.IsEmail(), m => $"Invalid email: {m.Email}", m => m.Email);
v.ErrorIf(m => m.Type == "Adult" && m.Age < 18, "Forbidden", m => m.Type, m => m.Age);
v.WarningIf(m => m.BirthDate >= DateTime.Now, "Looks like incorrect", m => m.BirthDate);
});
if (!result)
{
var ret = result.ToDictionary(); // Dictionary<PropertyName, ErrorMessage[]>
return TypedResults.ValidationProblem(ret); // for Minimal API
}
// or validate asynchronously
var result = await FlatValidator.ValidateAsync(model, v =>
{
v.ErrorIf(m => remoteApi.IsEmailBlockedAsync(m.Email),
m => $"Email {m.Email} is in black list.",
m => m.Email);
// the same with `async/await`
v.ErrorIf(async m => await remoteApi.IsEmailBlockedAsync(m.Email),
"Email is in black list.", m => m.Email);
});
// possibility to inspect occured validation failures:
bool success = result.IsValid;
var errors = result.Errors;
var warnings = result.Warnings;
2. Inheritance
Another way is to inherit the
FlatValidatorto define custom rules in the constructor. Also you can pass dependencies into constructor to get additional functionality inside of the validation rules.
public record UserModel(string Forename, string Surname, ....);
public class UserValidator: FlatValidator<UserModel>
{
public UserValidator(ILogger logger, IPostalService postalService)
{
logger.LogInfo("Validating...");
ErrorIf(m => m.Forename.IsEmpty() || m.Surname.IsEmpty(),
"Forename and Surname can not be empty.",
m => m.Forename, m => m.Surname);
// use 'When(...)' to control a validation flow
When(m => m.ShipmentAddress.NotEmpty(), @then: m =>
{
ValidIf(async m => await postalService.AddressExistsAsync(m.Address),
"Postal address not found.", m => m.Address);
WarningIf(m => !m.Phone.IsPhone(), "No contact phone.");
},
@else: m => // @else section is optional
{
ValidIf(m => m.Phone.IsPhone(), "Invalid phone number.", m => m.Phone);
});
}
}