implemented except in values validator (#1486)

Author: jonmchan

CHANGELOG.md

@@ -2,6 +2,7 @@
 ==================
 
 * [#1480](https://github.com/ruby-grape/grape/pull/1480): Use the ruby-grape-danger gem for PR linting - [@dblock](https://github.com/dblock).
+* [#1486](https://github.com/ruby-grape/grape/pull/1486): Implemented except in values validator - [@jonmchan](https://github.com/jonmchan).
 * Your contribution here.
 
 #### Fixes

README.md

@@ -1065,6 +1065,26 @@ params do
 end
 ```
 
+The values validator can also validate that the value is explicitly not within a specific
+set of values by passing ```except```. ```except``` accepts the same types of parameters as
+values (Procs, ranges, etc.).
+
+```ruby
+params do
+  requires :browsers, values: { except: [ 'ie6', 'ie7', 'ie8' ] }
+end
+```
+
+Values and except can be combined to define a range of accepted values while not allowing
+certain values within the set. Custom error messages can be defined for both when the parameter 
+passed falls within the ```except``` list or when it falls entirely outside the ```value``` list. 
+
+```ruby
+params do
+  requires :number, type: Integer, values: { value: 1..20 except: [4,13], except_message: 'includes unsafe numbers', message: 'is outside the range of numbers allowed' }
+end
+```
+
 #### `regexp`
 
 Parameters can be restricted to match a specific regular expression with the `:regexp` option. If the value

lib/grape/locale/en.yml

@@ -8,6 +8,7 @@ en:
         regexp: 'is invalid'
         blank: 'is empty'
         values: 'does not have a valid value'
+        except: 'has a value not allowed'
         missing_vendor_option:
           problem: 'missing :vendor option.'
           summary: 'when version using header, you must specify :vendor option. '

lib/grape/validations/validators/values.rb

@@ -2,7 +2,10 @@ module Grape
   module Validations
     class ValuesValidator < Base
       def initialize(attrs, options, required, scope)
-        @values = (options_key?(:value, options) ? options[:value] : options)
+        @excepts = (options_key?(:except, options) ? options[:except] : [])
+        @values = (options_key?(:value, options) ? options[:value] : [])
+
+        @values = options if @excepts == [] && @values == []
         super
       end
 
@@ -11,13 +14,24 @@ def validate_param!(attr_name, params)
         return unless params[attr_name] || required_for_root_scope?
 
         values = @values.is_a?(Proc) ? @values.call : @values
+        excepts = @excepts.is_a?(Proc) ? @excepts.call : @excepts
         param_array = params[attr_name].nil? ? [nil] : Array.wrap(params[attr_name])
-        return if param_array.all? { |param| values.include?(param) }
+
+        if param_array.all? { |param| excepts.include?(param) }
+          raise Grape::Exceptions::Validation, params: [@scope.full_name(attr_name)], message: except_message
+        end
+
+        return if (values.is_a?(Array) && values.empty?) || param_array.all? { |param| values.include?(param) }
         raise Grape::Exceptions::Validation, params: [@scope.full_name(attr_name)], message: message(:values)
       end
 
       private
 
+      def except_message
+        options = instance_variable_get(:@option)
+        options_key?(:except_message) ? options[:except_message] : message(:except)
+      end
+
       def required_for_root_scope?
         @required && @scope.root?
       end

spec/grape/validations/validators/values_spec.rb

@@ -4,6 +4,7 @@
   module ValidationsSpec
     class ValuesModel
       DEFAULT_VALUES = ['valid-type1', 'valid-type2', 'valid-type3'].freeze
+      DEFAULT_EXCEPTS = ['invalid-type1', 'invalid-type2', 'invalid-type3'].freeze
       class << self
         def values
           @values ||= []
@@ -14,6 +15,16 @@ def add_value(value)
           @values ||= []
           @values << value
         end
+
+        def excepts
+          @excepts ||= []
+          [DEFAULT_EXCEPTS + @excepts].flatten.uniq
+        end
+
+        def add_except(except)
+          @excepts ||= []
+          @excepts << except
+        end
       end
     end
 
@@ -35,6 +46,20 @@ class API < Grape::API
           get '/lambda' do
             { type: params[:type] }
           end
+
+          params do
+            requires :type, values: { except: ValuesModel.excepts, except_message: 'value is on exclusions list', message: 'default exclude message' }
+          end
+          get '/exclude/exclude_message' do
+            { type: params[:type] }
+          end
+
+          params do
+            requires :type, values: { except: ValuesModel.excepts, message: 'default exclude message' }
+          end
+          get '/exclude/fallback_message' do
+            { type: params[:type] }
+          end
         end
 
         params do
@@ -99,6 +124,20 @@ class API < Grape::API
           end
         end
         get '/optional_with_required_values'
+
+        params do
+          requires :type, values: { except: ValuesModel.excepts }
+        end
+        get '/except/exclusive' do
+          { type: params[:type] }
+        end
+
+        params do
+          requires :type, type: Integer, values: { value: 1..5, except: [3] }
+        end
+        get '/mixed/value/except' do
+          { type: params[:type] }
+        end
       end
     end
   end
@@ -135,6 +174,22 @@ def app
     end
   end
 
+  context 'with a custom exclude validation message' do
+    it 'does not allow an invalid value for a parameter' do
+      get('/custom_message/exclude/exclude_message', type: 'invalid-type1')
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type value is on exclusions list' }.to_json)
+    end
+  end
+
+  context 'exclude with a standard custom validation message' do
+    it 'does not allow an invalid value for a parameter' do
+      get('/custom_message/exclude/fallback_message', type: 'invalid-type1')
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type default exclude message' }.to_json)
+    end
+  end
+
   it 'allows a valid value for a parameter' do
     get('/', type: 'valid-type1')
     expect(last_response.status).to eq 200
@@ -321,4 +376,38 @@ def app
       expect(last_response.body).to eq('values does not have a valid value')
     end
   end
+
+  context 'exclusive excepts' do
+    it 'allows any other value outside excepts' do
+      get '/except/exclusive', type: 'value'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq({ type: 'value' }.to_json)
+    end
+
+    it 'rejects values that matches except' do
+      get '/except/exclusive', type: 'invalid-type1'
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type has a value not allowed' }.to_json)
+    end
+  end
+
+  context 'with mixed values and excepts' do
+    it 'allows value, but not in except' do
+      get '/mixed/value/except', type: 2
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq({ type: 2 }.to_json)
+    end
+
+    it 'rejects except' do
+      get '/mixed/value/except', type: 3
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type has a value not allowed' }.to_json)
+    end
+
+    it 'rejects outside except and outside value' do
+      get '/mixed/value/except', type: 10
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type does not have a valid value' }.to_json)
+    end
+  end
 end