validation

Validation

Flexible, multi-strategy validation for Go structs with support for struct tags, JSON Schema, and custom interfaces.

📚 Full Documentation: https://rivaas.dev/docs/guides/validation/

Documentation

• Installation - Get started
• User Guide - Learn validation strategies
• API Reference - Complete API docs
• Examples - Real-world patterns
• Troubleshooting - Common issues

Features

• Multiple Validation Strategies - Struct tags, JSON Schema, custom interfaces
• Partial Validation - PATCH request support with presence tracking
• Thread-Safe - Safe for concurrent use
• Security - Built-in redaction, nesting limits, memory protection
• Structured Errors - Field-level errors with codes and metadata
• Extensible - Custom tags, validators, and error messages

Installation

go get rivaas.dev/validation

Requires Go 1.25+

Quick Start

import "rivaas.dev/validation"

type User struct {
    Email string `json:"email" validate:"required,email"`
    Age   int    `json:"age" validate:"min=18"`
}

user := User{Email: "invalid", Age: 15}
if err := validation.Validate(ctx, &user); err != nil {
    var verr *validation.Error
    if errors.As(err, &verr) {
        for _, fieldErr := range verr.Fields {
            fmt.Printf("%s: %s\n", fieldErr.Path, fieldErr.Message)
        }
    }
}

Use errors.Is(err, validation.ErrValidation) and the package's sentinel errors for programmatic checks (see Error Handling).

The package-level Validate and ValidatePartial use DefaultEngine, which is lazily initialized. You can replace it in tests (e.g. validation.DefaultEngine = validation.MustNew(...) and restore in defer). For test isolation or multiple engines, create an Engine with New or MustNew and use engine.Validate instead.

Validation Strategies

1. Struct Tags

type User struct {
    Email string `validate:"required,email"`
    Age   int    `validate:"min=18,max=120"`
}

2. JSON Schema

func (u User) JSONSchema() (id, schema string) {
    return "user-v1", `{
        "type": "object",
        "properties": {
            "email": {"type": "string", "format": "email"},
            "age": {"type": "integer", "minimum": 18}
        },
        "required": ["email"]
    }`
}

3. Custom Interfaces

func (u *User) Validate() error {
    if !strings.Contains(u.Email, "@") {
        return errors.New("email must contain @")
    }
    return nil
}
// When using a pointer receiver, pass a pointer: validation.Validate(ctx, &user)

Learn More

• Basic Usage - Fundamentals
• Struct Tags - go-playground/validator syntax
• JSON Schema - Schema validation
• Custom Interfaces - Custom methods
• Partial Validation - PATCH requests
• Error Handling - Structured errors
• Security - Redaction and limits

Contributing

Contributions are welcome! Please see the main repository for contribution guidelines.

License

Apache License 2.0 - see LICENSE for details.

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Part of the Rivaas web framework ecosystem.