Allows to set a global ParamBuilder

CHANGELOG.md

@@ -3,6 +3,7 @@
 #### Features
 
 * Your contribution here.
+* [#1833](https://github.com/ruby-grape/grape/pull/1833): Allows to set the `ParamBuilder` globally - [@myxoh](https://github.com/myxoh).
 * [#1832](https://github.com/ruby-grape/grape/pull/1832): Support `body_name` in `desc` block - [@fotos](https://github.com/fotos).
 * [#1831](https://github.com/ruby-grape/grape/pull/1831): Support `security` in `desc` block - [@fotos](https://github.com/fotos).
 

README.md

@@ -22,13 +22,14 @@
   - [Rails](#rails)
   - [Modules](#modules)
 - [Remounting](#remounting)
-  - [Configuration](#configuration)
+  - [Mount Configuration](#mount-configuration)
 - [Versioning](#versioning)
   - [Path](#path)
   - [Header](#header)
   - [Accept-Version Header](#accept-version-header)
   - [Param](#param)
 - [Describing Methods](#describing-methods)
+- [Configuration](#configuration)
 - [Parameters](#parameters)
   - [Params Class](#params-class)
   - [Declared](#declared)
@@ -395,7 +396,7 @@ end
 
 Assuming that the post and comment endpoints are mounted in `/posts` and `/comments`, you should now be able to do `get /posts/votes`, `post /posts/votes`, `get /comments/votes`.
 
-### Configuration
+### Mount Configuration
 
 You can configure remountable endpoints for small details changing according to where they are mounted.
 
@@ -541,6 +542,29 @@ end
 
 [grape-swagger]: https://github.com/ruby-grape/grape-swagger
 
+## Configuration
+
+Grape counts with a module `Grape::Config` for some basic configuration at load time.
+Currently the configurable settings are:
+
+* `param_builder`: Sets the default [Parameter Builder](#parameters), by default: `Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder`
+
+To change a setting value make sure that at some point on load time the code the following code runs
+
+```ruby
+Grape::Config.configure do |config|
+  config.setting = value
+end
+```
+
+For example, for the `param_builder`, the following code could run in an initializers:
+
+```ruby
+Grape::Config.configure do |config|
+  config.param_builder = Grape::Extensions::Hashie::Mash::ParamBuilder
+end
+```
+
 ## Parameters
 
 Request parameters are available through the `params` hash object. This includes `GET`, `POST`
@@ -618,6 +642,8 @@ params do
 end
 ```
 
+Or globally with the [Configuration](#configuration) `Grape::Config.param_builder`
+
 In the example above, `params["color"]` will return `nil` since `params` is a plain `Hash`.
 
 Available parameter builders are `Grape::Extensions::Hash::ParamBuilder`, `Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder` and `Grape::Extensions::Hashie::Mash::ParamBuilder`.

lib/grape.rb

@@ -34,6 +34,7 @@ module Grape
     autoload :Namespace
 
     autoload :Path
+    autoload :Config
 
     autoload :Cookies
     autoload :Validations

lib/grape/config.rb

@@ -0,0 +1,27 @@
+module Grape
+  module Config
+    module SettingStore
+      ATTRIBUTES = %i[
+        param_builder
+      ].freeze
+
+      attr_accessor(*SettingStore::ATTRIBUTES)
+
+      def reset
+        self.param_builder = Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder
+      end
+
+      def configure
+        block_given? ? yield(self) : self
+      end
+
+      def config
+        self
+      end
+    end
+
+    Grape::Config.extend SettingStore
+  end
+end
+
+Grape::Config.reset

lib/grape/request.rb

@@ -5,7 +5,7 @@ class Request < Rack::Request
     alias rack_params params
 
     def initialize(env, options = {})
-      extend options[:build_params_with] || Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder
+      extend options[:build_params_with] || Grape::Config.param_builder
       super(env)
     end
 

spec/grape/config_spec.rb

@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+module Grape
+  describe Config do
+    let(:config_double) { Module.new { extend Config::SettingStore } }
+
+    context 'when configured' do
+      subject(:configure) do
+        config_double.configure do |config|
+          config.param_builder = 42
+        end
+      end
+
+      it 'changes the value' do
+        expect { configure }.to change { config_double.param_builder }.to(42)
+      end
+    end
+  end
+end

spec/grape/request_spec.rb

@@ -62,6 +62,24 @@ module Grape
       end
     end
 
+    describe 'when the param_builder is set to Hashie' do
+      before do
+        allow(Grape::Config).to receive(:param_builder) { Grape::Extensions::Hashie::Mash::ParamBuilder }
+      end
+
+      subject(:request_params) { Grape::Request.new(env, opts).params }
+
+      context 'when the API does not include a specific param builder' do
+        let(:opts) { {} }
+        it { is_expected.to be_a(Hashie::Mash) }
+      end
+
+      context 'when the API includes a specific param builder' do
+        let(:opts) { { build_params_with: Grape::Extensions::Hash::ParamBuilder } }
+        it { is_expected.to be_a(Hash) }
+      end
+    end
+
     describe '#headers' do
       let(:options) do
         default_options.merge(request_headers)