Top 5 Nuget Packages

Using these nuget projects consistently in most projects I'm building. See the examples in the details for usage.

FluentValidation

Install-Package FluentValidation

Doing user input validation can be tedious. This makes it less so.

public class CustomerValidator: AbstractValidator<Customer> {
    public CustomerValidator() {
        RuleFor(x => x.Surname).NotEmpty();
        RuleFor(x => x.Forename).NotEmpty().WithMessage("Please specify a first name");
        RuleFor(x => x.Discount).NotEqual(0).When(x => x.HasDiscount);
        RuleFor(x => x.Address).Length(20, 250);
        RuleFor(x => x.Postcode).Must(BeAValidPostcode).WithMessage("Please specify a valid postcode");
    }

    private bool BeAValidPostcode(string postcode) {
        // custom postcode validating logic goes here
    }
}

// Usage
var customer = new Customer();
var validator = new CustomerValidator();
ValidationResult results = validator.Validate(customer);

bool success = results.IsValid;
IList<ValidationFailure> failures = results.Errors;

GitHub reference

Microsoft.Extensions.DependencyInjection

Install-Package Microsoft.Extensions.DependencyInjection

Dependency injection aka inversion of control is a popular pattern. Lately I've stuck with the Microsoft version as it integrates nicely with ASP.net and fairly simple. Unit testing becomes easier since the interfaces can be mocked.

In this example, a service collection is created using interfaces with corresponding concrete implementation. Then one service is used within a scope.

var services = new ServiceCollection();
services.AddSingleton<IFoo>(new Foo());
services.AddScoped<IBar, Bar>();
var provider = services.BuildServiceProvider();

// usage
using var scope = _provider.CreateScope();
var instance = scope.ServiceProvider.GetService<IBar>();

Usage reference

Easy.Common

Install-Package Easy.Common

Have you ever tried counting lines of a very large file? If not, it can get complicated quick.

var file = new FileInfo("veryLargerFile.csv");
using var stream = file.OpenRead(); 
var lines = stream.CountLines();

There are other useful extensions. GitHub reference

Xunit, Moq, AutoMoq

Install-Package xunit
Install-Package Moq 
Install-Package AutoFixture.AutoMoq

Example of mocking

    [Fact]
    public async Task Can_get_message_from_cache() {

        // Arrange
        var expected = _fixture.Create<uint>();
        _mock.Setup(x => x.Get(expected))
            .Returns(_fixture
                .Build<Message>()
                .Do(x => x.Headers.Add("UID", expected.ToString()))
                .Create());

        // Act
        var message = await _provider.GetMessageAsync(expected);

        // Assert
        Assert.Equal(expected, uint.Parse(message.Headers["UID"]));
    }

Xunit getting started https://www.developerhandbook.com/unit-testing/writing-unit-tests-with-nunit-and-moq/#:~:text=Moq%20provides%20you%20methods%20to%20confirm%20that%20particular,was%20called%20a%20particular%20number%20of%20times.%20

Polly

Install-Package Polly

Need retry logic? Exponential back off? This project solves the problems easily with tons of of extensions!

var retryPolicy = Policy.Handle<TransientException>()
.WaitAndRetry(retryCount: 3, sleepDurationProvider: _ => TimeSpan.FromSeconds(1));

var attempt = 0;
retryPolicy.Execute(() =>
{
    Log($"Attempt {++attempt}");
    throw new TransientException();
});