Introduction

The aim of params-validator is to allow an easy way to validate the parameters in a method call.

Install

gem install params-validator

Requirements

v0.2.0 changes

• FEATURE: definition of validation rulesets inside the method, so it improves the code style including the validation as the first step in a method execution (suggested by osuka)

• FIXED: If a method has a ruleset that defines all the parameters as optional, a nil argument is allowed. On previous versions an ArgumentError exception was thrown

• FIXED: inheritance allowed. A method can define a more restrictive ruleset in a inherited method.

• FIXED: a method validation can be redefined, the first definition will not be used.

• MOVED: specs to folder ./spec

Usage

• There are four ways of use:

  • Include validation rules inside the object:

    require 'params-validator' class MockObject include ParamsValidator::ValidParams # define two useless methods [:method1, :method2].each{|m| define_method(m) do |*args, &block| puts {:foo => "bar"} true end } # method1 arguments ruleset validate_method(:method1) do level(Fixnum, :optional) end # method2 arguments ruleset validate_method(:method2) do data(String) { |data| !data.nil? and data.length > 0} level(Fixnum, :optional) {|level| level <= 3} end end

When calling a specific method, an ArgumentError exception will be raised if at least one parameter is invalid

    obj = MockObject.new
    obj.method1({:level => "1"})  # This will raise an ArgumentError exception because :level parameter type is invalid
    obj.method1({:level => 1})  # This will execute successfully the method call
    obj.method2({:level => 1})  # This will raise an ArgumentError exception because :data parameter is missing

• Include validation rules outside the object:

  class MockObject
    include ParamsValidator::ValidParams
    # define two useless methods 
    [:method1, :method2].each{|m|
      define_method(m) do |*args, &block|
        true
      end
    }
    # method1 and method2 should be validated, but no ruleset is defined
    validate_method [:method1, :method2]
  end
  

Then in a separate file, rulesets must be loaded:

    require 'params-validator'
    include ParamsValidator::ValidParams
    # define rulesets
    rules = <<EOF
      validation_rule("MockObject::method1") do
        level(Fixnum, :optional)
      end
      validation_rule("MockObject::method2") do
        data(String) { |data| !data.nil? and data.length > 0}
        level(Fixnum, :optional) {|level| level <= 3}
      end
    EOF
    # load rulesets in validation framework
    load_rules(rules)
    obj = MockObject.new
    obj.method1({:level => "1"})  # This will raise an ArgumentError exception because :level parameter type is invalid 
    obj.method1({:level => 1})  # This will execute successfully the method call
    obj.method2({:level => 1})  # This will raise an ArgumentError exception because :data parameter is missing

• Implicit validation: ruleset defined inside the method, kudos to osuka

  require 'params-validator'
  class MockObject
    include ParamsValidator::ValidParams
  
    def method1(args)
      validate_method(args) do
          level(Fixnum, :optional)
      end
    end
  end
  

• Client side validation, kudos to drslump

  obj = ParamsValidator::Request.new
  obj[:data] = "this is a log"
  obj[:level] = 1
  ruleset = MockObject.get_rule(:method2)
  obj.valid?(ruleset) # false
  begin
    obj.validate(ruleset)
  rescue ArgumentError => ae
    p ae.message  # array with validation errors
  end
  

More examples can be found in test folder.