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Fast and customizable validation library
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Phema.Validation.sln 3.1.1 Improve caching performance Aug 24, 2019
README.md

README.md

Phema.Validation

Build Status Nuget Nuget

A simple, lightweight, fluent and extensible validation library for .NET Core

Installation

$> dotnet add package Phema.Validation

Core concepts

  • IValidationContext - Scoped service to store all validation details
  • IValidationCondition - Contains a validation checks (e.g. Is(() => ...))
  • IValidationDetail - When IValidationCondition is not valid adds to IValidationContext.ValidationDetails
  • ValidationSeverity - Validation error level, used in IValidationContext.ValidationSeverity and IValidationDetail.ValidationSeverity
  • IValidationScope - Is a nested validation context with validation path and severity override

Usage (ASP.NET Core, HostedService examples)

// Add `IValidationContext` as scoped service
services.AddValidation(options => ...);

// Get or inject
var validationContext = serviceProvider.GetRequiredService<IValidationContext>();

// Validation key will be `Name` using default validation part provider
validationContext.When(person, p => p.Name)
  .Is(name => name == null)
  .AddValidationDetail("Name must be set");

// Validation key will be `Address.Locations[0].Latitude` using default validation part provider
validationContext.When(person, p => p.Address.Locations[0].Latitude)
  .Is(latitude => ...custom check...)
  .AddValidationDetail("Some custom check failed");

Validation conditions

  • Monads are not composable, so Is and IsNot, IsNull and IsNotNull... duplication
// Check for Phema.Validation.Conditions namespace
validationContext.When(person, p => p.Name)
  .IsNullOrWhitespace()
  .AddValidationDetail("Name must be set");

// Use multiple conditions (joined with AND)
validationContext.When(person, p => p.Name)
  .IsNotNull()
  // AND
  .HasLengthGreater(20)
  // .IsNull()
  // .IsEqual()
  // .IsNotUrl()
  // .IsNotEmail()
  // .IsMatch(regex)
  .AddValidationDetail("Name should be less than 20");

// DateTime conditions
validationContext.When(task, t => t.DueDate)
  .IsNotUtc()
  .AddValidationDetail("Due date must be in Utc");

// Type checks
validationContext.When(person, p => p.Car)
  .IsType<Ferrari>(typed => typed.Is(ferarriCar => ...Some Ferrari specific checks...))
  .AddValidationDetail("You have Ferrari car, but ...");

Validation details

var validationDetails = validationContext
  .When(person, p => p.Age)
  // Validation check is failed, validation condition is valid
  .Is(() => false)
  .AddValidationDetail("Age must be set");

// Use deconstruction
var (key, message) = validationContext
  .When(person, p => p.Age)
  .IsNull()
  .AddValidationDetail("Age must be set");

// More deconstruction
var (key, message, isValid) = validationContext
  .When(person, p => p.Age)
  .IsNull()
  .AddValidationDetail("Age must be set");

// Even more deconstruction!
var (key, message, isValid, severity) = validationContext
  .When(person, p => p.Age)
  .IsNull()
  .AddValidationDetail("Age must be set");

Check validation

// Throw exception when details severity greater than ValidationContext.ValidationSeverity
validationContext.When(person, p => p.Address)
  .IsNull()
  .AddValidationFatal("Address is not presented!!!"); // If invalid throw ValidationConditionException

// Check if context is valid
validationContext.IsValid();
validationContext.EnsureIsValid(); // If invalid throw ValidationContextException

// Check concrete validation details
validationContext.IsValid(person, p => p.Age);
validationContext.IsNotValid(person, p => p.Age);
validationContext.EnsureIsValid(person, p => p.Age);

Compose and reuse validation rules with extensions

  • Call is allocation free
  • Static checks
// Extensions
public static void ValidateCustomer(this IValidationContext validationContext, Customer customer)
{
  // Some checks
}

validationContext.ValidateCustomer(customer);
  • Write your own middleware or validation components/validators on top of IValidationContext

Validation part resolvers

  • ValidationPartResolver is a delegate, trying to get string valdiation part from MemberInfo
  • Use built in resolvers with ValidationPartResolvers static class: Default, DataMember, PascalCase, CamelCase
// Configure DataMember validation part resolver
services.AddValidation(options =>
  options.WithValidationPartResolver(ValidationPartResolvers.DataMember));

// Override validation parts with `DataMemberAttribute`
[DataMember(Name = "name")]
public string Name { get; set; }

Validation scopes

  • Use scopes when you need to have:
    • Same nested validation path multiple times
    • Empty validation details collection (syncing with parent context/scope)
    • ValidationSeverity override
// Validation key will be `Child.*ValidationPart*`
ValidateChild(validationContext.CreateScope(parent, p => p.Child))

// Validation key will be `Address.Locations[0].*ValidationPart*`
ValidateLocation(validationContext.CreateScope(person, p => p.Address.Locations[0]))

// Override local scope ValidationSeverity
using (var scope = validationContext.CreateScope(person, p => p.Address, ValidationSeverity.Warning))
{
  // Some scope validation checks syncing with validationContext
}

High performance with non-expression constructions

validationContext.When("key", value)
  .IsNull()
  .AddValidationDetail("Value is null");

validationContext.CreateScope("key", ValidationSeverity.Warning);

validationContext.IsValid("key");
validationContext.IsNotValid("key");
validationContext.EnsureIsValid("key");

Benchmarks (i7 9700k 3.60 GHz, 16Gb 3400 MHz)

  • Simpler expression = less costs
  • Try to use non-expression extensions in hot paths
  • Use CreateScope to not to repeat chained member calls (x => x.Property1.Property2[0].Property3)
  • Expression-based When with Is(value => ...) extensions use lazy expression compilation to get value (Invoke)

ValidationPartResolvers

Method Mean Error StdDev Median Allocated
Default 1.307 us 0.0031 us 0.0903 us 1.309 us 936 B
DataMember_WithAttribute 6.904 us 0.0105 us 0.2985 us 6.909 us 2398 B
DataMember_WithoutAttribute 1.983 us 0.0050 us 0.1465 us 1.991 us 1430 B
PascalCase_Lower 1.604 us 0.0046 us 0.1333 us 1.572 us 1048 B
PascalCase 1.365 us 0.0038 us 0.1132 us 1.366 us 936 B
CamelCase_Upper 1.549 us 0.0035 us 0.0986 us 1.569 us 1040 B
CamelCase 1.432 us 0.0037 us 0.1092 us 1.434 us 936 B

Non-expression validation

Method Mean Error StdDev Median Allocated
Simple 215.7 ns 0.9524 ns 27.52 ns 225.0 ns 266 B
CreateScope 119.7 ns 0.5997 ns 17.87 ns 128.1 ns 112 B
IsValid 219.3 ns 0.6558 ns 19.38 ns 228.1 ns 424 B
EnsureIsValid 218.2 ns 0.6113 ns 17.72 ns 225.0 ns 424 B

Expression validation

Method Mean Error StdDev Median Allocated
SimpleExpression 1,216.5 ns 2.0927 ns 60.78 ns 1,231.2 ns 914 B
SimpleExpression_CompiledValue 1,437.8 ns 2.2016 ns 62.72 ns 1,456.2 ns 1010 B
ChainedExpression 1,680.5 ns 3.0921 ns 90.31 ns 1,712.5 ns 1258 B
ChainedExpression_CompiledValue 1,908.5 ns 3.4080 ns 99.13 ns 1,940.6 ns 1354 B
ArrayAccessExpression 1,766.2 ns 3.5956 ns 103.22 ns 1,803.1 ns 1410 B
ArrayAccessExpression_CompiledValue 2,002.5 ns 4.0274 ns 117.76 ns 2,056.2 ns 1506 B
ChainedArrayAccessExpression 2,312.1 ns 4.5806 ns 133.17 ns 2,368.8 ns 1770 B
ChainedArrayAccessExpression_CompiledValue 2,542.6 ns 5.6628 ns 164.75 ns 2,593.8 ns 1866 B
ChainedArrayAccess 3,998.3 ns 9.4951 ns 275.09 ns 4,078.1 ns 2715 B
ChainedArrayAccess_CompiledValue 4,669.4 ns 9.7369 ns 283.27 ns 4,790.6 ns 2802 B
CreateScope_SimpleExpression 1,050.5 ns 1.2892 ns 37.55 ns 1,053.1 ns 736 B
CreateScope_ChainedExpression 1,375.0 ns 1.3573 ns 39.32 ns 1,375.0 ns 1080 B
IsValid_Empty 113.1 ns 0.6117 ns 17.99 ns 121.9 ns 184 B
IsValid_Expression 1,155.1 ns 1.0107 ns 28.99 ns 1,150.0 ns 1048 B
EnsureIsValid_Expression 1,098.0 ns 1.1002 ns 31.19 ns 1,095.3 ns 1048 B
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