Rails Validation API

Enhanced parameter validation system for Rails APIs with automatic controller integration.

Rails Validation API provides a powerful DSL for validating request parameters in Rails applications. Features include automatic validator loading based on controller/action names, nested parameter validation, custom error handling, and seamless integration with Rails controllers through concerns. Perfect for API applications requiring robust parameter validation with minimal boilerplate code.

Add this line to your application's Gemfile:

gem 'rails_validation_api'

And then execute:

bundle install

Or install it yourself as:

gem install rails_validation_api

After installing the gem, run the install command to set up the necessary files:

This will generate the required application validator structure in your Rails application.

The gem provides automatic parameter validation through Rails controller concerns. It automatically loads validators based on controller and action names.

class API::UsersController < ApplicationController
  require "auto_load_rails_validation_api"
  include AutoLoadRailsValidation

  def create
    # Parameters are automatically validated using API::ValidateParameters::UsersValidator
    # and API::UsersValidator (if they exist)
    
    # Your controller logic here
    render json: { message: "User created successfully" }
  end
end

# app/validators/api/validate_parameters/users_validator.rb
class API::ValidateParameters::UsersValidator
  FIELDS_VALIDATES = {
    name: { required: true, type: String },
    email: { required: true, type: String, format: /@/ },
    age: { required: false, type: Integer, min: 18 }
  }

  def create
    FIELDS_VALIDATES.slice(:name, :email, :age)
  end

  def update
    FIELDS_VALIDATES.slice(:name, :email)
  end
end

Generate both parameter and business logic validators for a given name:

bundle exec rails_validation_api generate users

This creates:

• app/validators/api/validate_parameters/users_validator.rb - Parameter validation
• app/validators/api/users_validator.rb - Business logic validation

Remove validators for a given name:

bundle exec rails_validation_api destroy users

This removes both parameter and business logic validators.

The gem uses a DSL approach for defining validation rules:

# Using RailsValidation.build
validator = RailsValidation.build do
  param! :name, String, required: true
  param! :email, String, required: true, format: /@/
  param! :profile do
    param! :age, Integer, required: false, min: 18
    param! :city, String, required: true
  end
end

# Validate parameters
begin
  validator.validate(params)
rescue RailsValidation::Error => e
  render json: { errors: e.message }, status: 422
end

• Automatic Loading: Validators are automatically loaded based on controller/action names
• Nested Validation: Support for validating nested Hash/Array parameters
• Custom Error Handling: Detailed error messages with field context
• Rails Integration: Seamless integration through Rails controller concerns
• DSL Support: Flexible DSL for defining validation rules
• Generator Commands: Easy validator generation and management

Run the test example:

ruby runtest.rb

gem build rails_validation_api.gemspec
gem install rails_validation_api-*.gem

• rails_param (~> 0.9.0) - Core parameter validation logic
• activesupport (>= 6.0) - For Rails utilities and concerns
• activemodel (>= 6.0) - For model validation features

Bug reports and pull requests are welcome on GitHub at https://github.com/linhnq-cs/rails_vailidation_api.

The gem is available as open source under the terms of the MIT License.