Revamp array validator

[mourad-ifeelgoods]

Introduce a new ApiPie Array validator for more flexible validations
The following validation are currently supported

• Validates all items of an array has the specified type

• Validates all items are in a set of values

  example 1
  Assert hits must be an array of integer value

    param :hits, Array, of: Integer

  example 2
  Assert each items of colors to be in the enumeration

    param :colors, Array, in: [ "red", "green", "blue"] 

  example 3
  The load of enum can be deferred until needed. this useful when the enum may changes

    param :colors, Array, in: ->  { Color.all.pluck(:name) }

  example 4
  Assert things is an array of any type

     param :things, Array

Notes

This is a first try for a more consistent validator dsl. I want a uniform way to express constraints on parameters. The validators are build around a set of core types String, Number, Boolean, Array and Hash

param :id, :integer
param :title, :string
param :draft :boolean
param :tags: :array
param :author, :hash do
  param :name, :string
end

it would would simple to extend our validations by adding additional constraints

param :id, :integer, min_value: 1
param :title, :string
param :status, :string, enum: %w(draft proposed published)
param :tags: :array, of: :string, max_term: 10, unique: true
param :author, :hash do
  param :name, :string
  param :email, :string, pattern: /\A\S+@.+\.\S+\z/
end

or by defining custom validators.

param :address, :email

The validator class would be found by naming convention

class EmailValidator < Apipie::Validator
  def validate(param, value)
     value ~=  /\A\S+@.+\.\S+\z/
  end
end

[mtparet]

Nice PR!

[mtparet]

should be better to only allow lambda for code safety ?

[mourad-ifeelgoods]

block is eventually a block of nested param. it is not a lambda.
currently this validator does not support nested object we just skip this param. it will be handle by NestedValidator

[mtparet]

@iNecas any thoughts on this PR ?

[iNecas]

Nice one! Could you add some notes to the readme for the documentation purposes?

[dali-ifg]

@iNecas do the readme updates match your expectation?

[iNecas]

They do, thanks for the notification: would be nice if github notified about new commits in the PR,merging now.

[iNecas]

The changes were released as part of the 0.2.3 release. Thanks for your contribution! Let the code be with you!