Lyo.Validation 2.0.0

Lyo.Validation

Fluent rule builders, C# validators, validation attributes, and adapters that return structured Lyo.Result.Result<T> failures. Errors are populated through Lyo.Result.Error so callers can render Problem Details, log structurally, or aggregate into BulkResult.

Schemas are named WhereClause documents (ValidationSchema) that hosts load from an API or Lyo.Validation.Postgres. Evaluation reuses IWhereClauseService.ExplainMatch. Failed nodes become errors via WhereClauseExplainResult.ToErrors.

Features

• Fluent + attributes. PropertyValidatorBuilder<T, TProperty> / ValidatorBuilder<T> and AttributeValidator<T>.
• Schema documents. ValidationSchema keyed by name, optional target type, WhereClause constraints (NotIn, In, Regex, and similar).
• Store. IValidationSchemaStore (in-memory default. Postgres in a sibling package).
• Error mapping. WhereClauseExplainResult.ToErrors in Query.Models (not a Validation-local builder).

Examples

Usual usage

using Lyo.Validation;

var validator = ValidatorBuilder<CreateUserRequest>.Create()
    .RuleFor(x => x.Name)
    .NotWhiteSpace()
    .Length(2, 50)
    .RuleFor(x => x.Email)
    .Email()
    .RuleFor(x => x.Age)
    .InclusiveBetween(18, 120)
    .Build();

var result = validator.Validate(new CreateUserRequest { Name = "Matt", Email = "matt@example.com", Age = 33 });

Validate via attributes

public sealed class CreateUserRequest {
    [NotWhiteSpace]
    [Length(2, 50)]
    public string Name { get; init; } = string.Empty;

    [Email]
    public string Email { get; init; } = string.Empty;

    [Range(18, 120)]
    public int Age { get; init; }
}

Result<CreateUserRequest> result = new CreateUserRequest { /* ... */ }.ValidateWithAttributes();

Load a schema built from WhereClause

services.AddLyoQueryServices();
services.AddValidation();
services.AddQueryValidationEvaluator();
// or services.AddPostgresValidationStoreFromConfiguration(configuration);

var validator = await compiler.GetAsync<CreateUserRequest>("signup.v2", ct);
var result = validator.Validate(request);

Package contents

• Fluent validator composition via PropertyValidatorBuilder<T, TProperty> and ValidatorBuilder<T> (including NotIn / In for scalar allow-lists).
• Attribute-based validation through built-in attributes such as NotEmpty, Required, NotWhiteSpace, Length, Regex, Phone, Email, Uri, and Range (in Lyo.Validation.Attributes).
• Data-driven ValidationSchema documents: a named WhereClause tree (same operators as query filters) compiled to IValidator<T> via IValidationSchemaCompiler.
• AttributeValidator<T> for reflection-driven validation across both Lyo's ValidationAttributeBase and System.ComponentModel.DataAnnotations (including IValidatableObject).
• Structured property metadata via ValidationMetadataKeys (AttemptedValue, PropertyName) attached to each failing Error.Metadata.
• Stable error codes via Lyo.Result.ValidationErrorCodes (e.g. EmptyValue, NullValue, InvalidLength, InvalidEmail, OutOfRange, ValidationFailed).

Validate via attributes

Public instance-readable properties on T are what AttributeValidator<T> validates (compiled getters are cached statically per T). Lyo ValidationAttributeBase attributes run together with System.ComponentModel.DataAnnotations.ValidationAttribute. When T is an IValidatableObject, Validate(ValidationContext) runs as well. The cached singleton is AttributeValidator<T>.Shared; value.ValidateWithAttributes() is the call that uses it.

Lyo.Result.ValidationErrorCodes is where DataAnnotations codes land (RequiredAttribute → RequiredValue, EmailAddressAttribute → InvalidEmail, RangeAttribute → OutOfRange). Unmapped attributes become ValidationFailed.

Schemas backed by a database

ValidationSchema is the wire DTO hosts PUT/GET on their own API. Constraints are a polymorphic WhereClause ($type: group / condition) using ComparisonOperatorEnum (In, Equals, NotIn, Regex, …). An instance is valid iff the query engine reports a match.

Register AddValidation() plus AddQueryValidationEvaluator() (after AddLyoQueryServices()). Persist with Lyo.Validation.Postgres (AddPostgresValidationStoreFromConfiguration). WhereClauseValidator<T> calls ExplainMatch then ToErrors. Do not add a second error mapper in API code.

Dependencies

Generated from ProjectReference / PackageReference (same model as docs/Lyo.ProjectGraph.html).

• Lyo.Common.Core (direct, lyo)
• Lyo.Exceptions (direct, lyo)
• Lyo.Query.Evaluation (direct, lyo)
• Lyo.Query.Models (direct, lyo)
• Lyo.Result (direct, lyo)
• Lyo.Validation.Models (direct, lyo)
• Microsoft.Extensions.DependencyInjection.Abstractions 10.0.5 (direct, microsoft)
• System.ComponentModel.Annotations 5.0.0 (direct, microsoft)
• Lyo.Common.Json (transitive, lyo)
• Lyo.Common.Metadata (transitive, lyo)
• Lyo.Metrics (transitive, lyo)
• Lyo.Parameters (transitive, lyo)
• Microsoft.Bcl.AsyncInterfaces 10.0.5 (transitive, microsoft, netstandard2.0)
• System.Memory 4.6.3 (transitive, microsoft, netstandard2.0)
• System.Text.Json 10.0.5 (transitive, microsoft, netstandard2.0)