WeakParameters

Validates params in your controller.

Installation

gem "weak_parameters"

Usage

class ApplicationController < ActionController::Base
  protect_from_forgery

  respond_to :json

  rescue_from WeakParameters::ValidationError do
    head 400
  end
end

# WeakParameters provides `validates` class method to define validations.
class RecipesController < ApplicationController
  validates :create do
    string :name, required: true, except: ["charlie", "dave"]
    integer :type, only: 1..3
    string :quantity do |value|
      value =~ /\A\d+(?:\.\d+)g\z/
    end
  end

  def create
    respond_with Recipe.create(params.slice(:name, :type))
  end
end
irb(main):001:0> app.accept = "application/json"
=> "application/json"
irb(main):002:0> app.post "/recipes", name: "alice", type: 1
=> 201
irb(main):003:0> app.post "/recipes", name: "alice"
=> 201
irb(main):004:0> app.post "/recipes", type: 1
=> 400
irb(main):005:0> app.post "/recipes", name: "alice", type: "bob"
=> 400

Available validators

  • any
  • array
  • float
  • hash
  • integer
  • string
  • boolean (= 0, 1, false, true)
  • file
  • object
  • list

Avilable options

  • required
  • only
  • except
  • handler

Tips

WeakParameters.stats returns its validation metadata, and this is useful for auto-generating API documents. With autodoc, you can auto-generate API documents with params information.

https://github.com/r7kamura/autodoc