Allow validation of nested parameters.

Passing the scope to the validators, so they can take the relevant parameters.

Using the group syntax which allows for:

group :user do
  group :admin do
    requires :first_name, :last_name
  end
end

lib/grape/validations.rb

@@ -8,16 +8,19 @@ module Validations
     # All validators must inherit from this class.
     # 
     class Validator
-      def initialize(attrs, options, required)
+      def initialize(attrs, options, required, scope)
         @attrs = Array(attrs)
         @required = required
+        @scope = scope
 
         if options.is_a?(Hash) && !options.empty?
           raise "unknown options: #{options.keys}"
         end
       end
 
       def validate!(params)
+        params = @scope.params(params)
+
         @attrs.each do |attr_name|
           if @required || params.has_key?(attr_name)
             validate_param!(attr_name, params)
@@ -40,7 +43,7 @@ def self.convert_to_short_name(klass)
     ##
     # Base class for all validators taking only one param.
     class SingleOptionValidator < Validator
-      def initialize(attrs, options, required)
+      def initialize(attrs, options, required, scope)
         @option = options
         super
       end
@@ -67,7 +70,11 @@ def self.register_validator(short_name, klass)
     end
 
     class ParamsScope
-      def initialize(api, &block)
+      attr_accessor :element, :parent
+
+      def initialize(api, element, parent, &block)
+        @element = element
+        @parent = parent
         @api = api
         instance_eval(&block)
       end
@@ -89,7 +96,17 @@ def optional(*attrs)
 
         validates(attrs, validations)
       end
-
+
+      def group(element, &block)
+        scope = ParamsScope.new(@api, element, self, &block)
+      end
+
+      def params(params)
+        params = @parent.params(params) if @parent
+        params = params[@element] || {} if @element
+        params
+      end
+
     private
       def validates(attrs, validations)
         doc_attrs = { :required => validations.keys.include?(:presence) }
@@ -130,7 +147,7 @@ def validates(attrs, validations)
       def validate(type, options, attrs, doc_attrs)
         validator_class = Validations::validators[type.to_s]
         if validator_class
-          @api.settings[:validations] << validator_class.new(attrs, options, doc_attrs[:required])
+          @api.settings[:validations] << validator_class.new(attrs, options, doc_attrs[:required], self)
         else
           raise "unknown validator: #{type}"
         end
@@ -145,7 +162,7 @@ def reset_validations!
       end
 
       def params(&block)
-        ParamsScope.new(self, &block)
+        ParamsScope.new(self, nil, nil, &block)
       end
 
       def document_attribute(names, opts)

spec/grape/validations/coerce_spec.rb

@@ -111,6 +111,19 @@ class User
         last_response.status.should == 201
         last_response.body.should == File.basename(__FILE__).to_s
       end
+
+      it 'Nests integers' do
+        subject.params do
+          group :integers do
+            requires :int, :coerce => Integer
+          end
+        end
+        subject.get '/int' do params[:integers][:int].class; end
+
+        get '/int', { :integers => { :int => "45" } }
+        last_response.status.should == 200
+        last_response.body.should == 'Fixnum'
+      end
     end
   end
 end

spec/grape/validations/presence_spec.rb

@@ -26,6 +26,29 @@ class API < Grape::API
         get do
           "Hello"
         end
+
+        params do
+          group :user do
+            requires :first_name, :last_name
+          end
+        end
+        get '/nested' do
+          "Nested"
+        end
+
+        params do
+          group :admin do
+            requires :admin_name
+            group :super do
+              group :user do
+                requires :first_name, :last_name
+              end
+            end
+          end
+        end
+        get '/nested_triple' do
+          "Nested triple"
+        end
       end
     end
   end
@@ -67,5 +90,49 @@ def app
     last_response.status.should == 200
     last_response.body.should == "Hello"
   end
-
+
+  it 'validates nested parameters' do
+    get('/nested')
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: first_name"
+
+    get('/nested', :user => {:first_name => "Billy"})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: last_name"
+
+    get('/nested', :user => {:first_name => "Billy", :last_name => "Bob"})
+    last_response.status.should == 200
+    last_response.body.should == "Nested"
+  end
+
+  it 'validates triple nested parameters' do
+    get('/nested_triple')
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: admin_name"
+
+    get('/nested_triple', :user => {:first_name => "Billy"})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: admin_name"
+
+    get('/nested_triple', :admin => {:super => {:first_name => "Billy"}})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: admin_name"
+
+    get('/nested_triple', :super => {:user => {:first_name => "Billy", :last_name => "Bob"}})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: admin_name"
+
+    get('/nested_triple', :admin => {:super => {:user => {:first_name => "Billy"}}})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: admin_name"
+
+    get('/nested_triple', :admin => { :admin_name => 'admin', :super => {:user => {:first_name => "Billy"}}})
+    last_response.status.should == 400
+    last_response.body.should == "missing parameter: last_name"
+
+    get('/nested_triple', :admin => { :admin_name => 'admin', :super => {:user => {:first_name => "Billy", :last_name => "Bob"}}})
+    last_response.status.should == 200
+    last_response.body.should == "Nested triple"
+  end
+
 end