Added param validator for an allowed list of values.

CHANGELOG.md

@@ -4,6 +4,7 @@ Next Release
 #### Features
 
 * [#475](https://github.com/intridea/grape/pull/475): Added support for the `:jsonapi`, `application/vnd.api+json` media type registered at http://jsonapi.org - [@bcm](https://github.com/bcm).
+* [#471](https://github.com/intridea/grape/issues/471): Added parameter validator for a list of allowed values - [@vickychijwani](https://github.com/vickychijwani).
 * Your contribution here.
 
 0.6.0 (9/16/2013)

README.md

@@ -335,7 +335,7 @@ params do
     requires :url
   end
   optional :audio do
-    requires :mp3
+    requires :format, type: Symbol, values: [:mp3, :wav, :aac, :ogg], default: :mp3
   end
 end
 put ':id' do
@@ -354,6 +354,14 @@ params do
 end
 ```
 
+Parameters can be restricted to a specific set of values with the `:values` option.
+
+```ruby
+params do
+  requires :status, type: Symbol, values: [:not_started, :processing, :done]
+end
+```
+
 Parameters can be nested using `group` or by calling `requires` or `optional` with a block.
 In the above example, this means `params[:media][:url]` is required along with `params[:id]`,
 and `params[:audio][:mp3]` is required only if `params[:audio]` is present.

lib/grape.rb

@@ -44,6 +44,7 @@ module Exceptions
     autoload :UnknownValidator,               'grape/exceptions/unknown_validator'
     autoload :UnknownOptions,                 'grape/exceptions/unknown_options'
     autoload :InvalidWithOptionForRepresent,  'grape/exceptions/invalid_with_option_for_represent'
+    autoload :IncompatibleOptionValues,       'grape/exceptions/incompatible_option_values'
   end
 
   module ErrorFormatter

lib/grape/exceptions/incompatible_option_values.rb

@@ -0,0 +1,13 @@
+# encoding: utf-8
+module Grape
+  module Exceptions
+    class IncompatibleOptionValues < Base
+
+      def initialize(option1, value1, option2, value2)
+        super(message: compose_message("incompatible_option_values", option1: option1, value1: value1, option2: option2, value2: value2))
+      end
+
+    end
+
+  end
+end

lib/grape/locale/en.yml

@@ -6,6 +6,7 @@ en:
         coerce: 'is invalid'
         presence: 'is missing'
         regexp: 'is invalid'
+        values: 'does not have a valid value'
         missing_vendor_option:
           problem: 'missing :vendor option.'
           summary: 'when version using header, you must specify :vendor option. '
@@ -26,3 +27,4 @@ en:
           resolution: 'available strategy for :using is :path, :header, :param'
         unknown_validator: 'unknown validator: %{validator_type}'
         unknown_options: 'unknown options: %{options}'
+        incompatible_option_values: '%{option1}: %{value1} is incompatible with %{option2}: %{value2}'

lib/grape/validations.rb

@@ -189,6 +189,20 @@ def validates(attrs, validations)
           doc_attrs[:default] = default
         end
 
+        if values = validations[:values]
+          doc_attrs[:values] = values
+        end
+
+        # default value should be present in values array, if both exist
+        if default && values && (! values.include? default)
+          raise Grape::Exceptions::IncompatibleOptionValues.new(:default, default, :values, values)
+        end
+
+        # type should be compatible with values array, if both exist
+        if coerce_type && values && values.any? { |v| not v.instance_of? coerce_type }
+          raise Grape::Exceptions::IncompatibleOptionValues.new(:type, coerce_type, :values, values)
+        end
+
         full_attrs = attrs.collect{ |name| { :name => name, :full_name => full_name(name)} }
         @api.document_attribute(full_attrs, doc_attrs)
 

lib/grape/validations/values.rb

@@ -0,0 +1,16 @@
+module Grape
+  module Validations
+    class ValuesValidator < Validator
+      def initialize(attrs, options, required, scope)
+        @values = options
+        super
+      end
+
+      def validate_param!(attr_name, params)
+        if params[attr_name] && (! @values.include? params[attr_name])
+          raise Grape::Exceptions::Validation, param: @scope.full_name(attr_name), message_key: :values
+        end
+      end
+    end
+  end
+end

spec/grape/validations/values_spec.rb

@@ -0,0 +1,64 @@
+require 'spec_helper'
+
+describe Grape::Validations::ValuesValidator do
+
+  module ValidationsSpec
+    module ValuesValidatorSpec
+      class API < Grape::API
+        default_format :json
+
+        params do
+          requires :type, values: ['valid-type1', 'valid-type2', 'valid-type3']
+        end
+        get '/' do
+          { type: params[:type] }
+        end
+
+        params do
+          optional :type, values: ['valid-type1', 'valid-type2', 'valid-type3'], default: 'valid-type2'
+        end
+        get '/default/valid' do
+          { type: params[:type] }
+        end
+
+      end
+    end
+  end
+
+  def app
+    ValidationsSpec::ValuesValidatorSpec::API
+  end
+
+  it 'allows a valid value for a parameter' do
+    get("/", type: 'valid-type1')
+    last_response.status.should eq 200
+    last_response.body.should eq({ type: "valid-type1" }.to_json)
+  end
+
+  it 'does not allow an invalid value for a parameter' do
+    get("/", type: 'invalid-type')
+    last_response.status.should eq 400
+    last_response.body.should eq({ error: "type does not have a valid value" }.to_json)
+  end
+
+  it 'allows a valid default value' do
+    get("/default/valid")
+    last_response.status.should eq 200
+    last_response.body.should eq({ type: "valid-type2" }.to_json)
+  end
+
+  it 'raises IncompatibleOptionValues on an invalid default value' do
+    subject = Class.new(Grape::API)
+    expect {
+      subject.params { optional :type, values: ['valid-type1', 'valid-type2', 'valid-type3'], default: 'invalid-type' }
+    }.to raise_error Grape::Exceptions::IncompatibleOptionValues
+  end
+
+  it 'raises IncompatibleOptionValues when type is incompatible with values array' do
+    subject = Class.new(Grape::API)
+    expect {
+      subject.params { optional :type, values: ['valid-type1', 'valid-type2', 'valid-type3'], type: Symbol }
+    }.to raise_error Grape::Exceptions::IncompatibleOptionValues
+  end
+
+end