support Array with index

CHANGELOG.md

@@ -11,6 +11,7 @@
 * [#1252](https://github.com/ruby-grape/grape/pull/1252): Allow default to be a subset or equal to allowed values without raising IncompatibleOptionValues - [@jeradphelps](https://github.com/jeradphelps).
 * [#1255](https://github.com/ruby-grape/grape/pull/1255): Allow param type definition in `route_param` - [@namusyaka](https://github.com/namusyaka).
 * [#1257](https://github.com/ruby-grape/grape/pull/1257): Allow Proc, Symbol or String in `rescue_from with: ...` - [@namusyaka](https://github.com/namusyaka).
+* [#1261](https://github.com/ruby-grape/grape/pull/1261): support array with index - [@itoufo](https://github.com/itoufo).
 * Your contribution here.
 
 #### Fixes

README.md

@@ -912,6 +912,31 @@ params do
 end
 ```
 
+If type is Array, It support following kinds of parameter.
+#### Array
+```sh
+#without index
+curl -X POST http://localhost:9292/api/v1/preference.json -d \
+  &preferences[][key]=foo \
+  &preferences[][value]=100 \
+  &preferences[][key]=bar \
+  &preferences[][value]=200
+
+#with index
+curl -X POST http://localhost:9292/api/v1/preference.json -d \
+  &preferences[0][key]=foo \
+  &preferences[1][key]=bar \
+  &preferences[0][value]=100 \
+  &preferences[1][value]=200
+```
+
+#### Hash
+```sh
+curl -X POST http://localhost:9292/api/v1/preference.json -d \
+  &preferences[key]=foo \
+  &preferences[value]=100 \
+````
+
 ### Dependent Parameters
 
 Suppose some of your parameters are only relevant if another parameter is given;

lib/grape.rb

@@ -129,6 +129,7 @@ module Util
     autoload :InheritableSetting
     autoload :StrictHashConfiguration
     autoload :FileResponse
+    autoload :HashParameter
   end
 
   module DSL

lib/grape/dsl/parameters.rb

@@ -8,6 +8,8 @@ module DSL
     module Parameters
       extend ActiveSupport::Concern
 
+      include Grape::Util::HashParameter
+
       # Include reusable params rules among current.
       # You can define reusable params with helpers method.
       #
@@ -188,6 +190,7 @@ def declared_param?(param)
       # @api private
       def params(params)
         params = @parent.params(params) if @parent
+
         if @element
           if params.is_a?(Array)
             params = params.flat_map { |el| el[@element] || {} }
@@ -197,6 +200,9 @@ def params(params)
             params = {}
           end
         end
+
+        params = params.values if params.is_a?(Hash) && deem_hash_array?(params)
+
         params
       end
     end

lib/grape/util/hash_parameter.rb

@@ -0,0 +1,20 @@
+require 'active_support/concern'
+module Grape
+  module Util
+    module HashParameter
+      extend ActiveSupport::Concern
+
+      def deem_hash_array?(hash)
+        return false unless hash.is_a?(Hash) && hash.keys.any? { |key| integer_string?(key) }
+        true
+      end
+
+      def integer_string?(str)
+        Integer(str)
+        true
+      rescue ArgumentError, TypeError
+        false
+      end
+    end
+  end
+end

lib/grape/validations/validators/base.rb

@@ -3,6 +3,8 @@ module Validations
     class Base
       attr_reader :attrs
 
+      include Grape::Util::HashParameter
+
       # Creates a new Validator from options specified
       # by a +requires+ or +optional+ directive during
       # parameter definition.

lib/grape/validations/validators/coerce.rb

@@ -36,8 +36,10 @@ def valid_type?(val)
 
         # Allow nil, to ignore when a parameter is absent
         return true if val.nil?
-
-        converter.value_coerced? val
+        unless !type.is_a?(Types::VariantCollectionCoercer) && type == Array && val.is_a?(Hash) && deem_hash_array?(val)
+          return converter.value_coerced? val
+        end
+        true
       end
 
       def coerce_value(val)

spec/grape/validations/validators/default_spec.rb

@@ -99,6 +99,12 @@ def app
     expect(last_response.body).to eq({ array: [{ name: 'name', with_default: 'default' }, { name: 'name2', with_default: 'bar2' }] }.to_json)
   end
 
+  it 'sets default values for grouped arrays with index' do
+    get('/array?array[0][name]=name&array[1][name]=name2&array[0][with_default]=bar1')
+    expect(last_response.status).to eq(200)
+    expect(last_response.body).to eq({ array: { 0 => { name: 'name', with_default: 'bar1' }, 1 => { name: 'name2', with_default: 'default' } } }.to_json)
+  end
+
   context 'optional group with defaults' do
     subject do
       Class.new(Grape::API) do