Add `ActionController::ParamsWrapper` to wrap parameters into a nested hash

This will allow us to do a rootless JSON/XML request to server.

1 files changed, 197 insertions, 0 deletions

diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
new file mode 100644
index 0000000000..29ff546139
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -0,0 +1,197 @@
+require 'active_support/core_ext/class/attribute'
+require 'action_dispatch/http/mime_types'
+
+module ActionController
+  # Wraps parameters hash into nested hash. This will allow client to submit
+  # POST request without having to specify a root element in it.
+  #
+  # By default, this functionality won't be enabled by default. You can enable
+  # it globally by setting +ActionController::Base.wrap_parameters+:
+  #
+  #     ActionController::Base.wrap_parameters = [:json]
+  #
+  # You could also turn it on per controller by setting the format array to
+  # non-empty array:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters :format => [:json, :xml]
+  #     end
+  #
+  # If you enable +ParamsWrapper+ for +:json+ format. Instead of having to
+  # send JSON parameters like this:
+  #
+  #     {"user": {"name": "Konata"}}
+  #
+  # You can now just send a parameters like this:
+  #
+  #     {"name": "Konata"}
+  #
+  # And it will be wrapped into a nested hash with the key name matching
+  # controller's name. For example, if you're posting to +UsersController+,
+  # your new +params+ hash will look like this:
+  #
+  #     {"name" => "Konata", "user" => {"name" => "Konata"}}
+  #
+  # You can also specify the key in which the parameters should be wrapped to,
+  # and also the list of attributes it should wrap by using either +:only+ or
+  # +:except+ options like this:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters :person, :only => [:username, :password]
+  #     end
+  #
+  # If you're going to pass the parameters to an +ActiveModel+ object (such as
+  # +User.new(params[:user])+), you might consider passing the model class to
+  # the method instead. The +ParamsWrapper+ will actually try to determine the
+  # list of attribute names from the model and only wrap those attributes:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters Person
+  #     end
+  #
+  # You still could pass +:only+ and +:except+ to set the list of attributes
+  # you want to wrap.
+  #
+  # By default, if you don't specify the key in which the parameters would be
+  # wrapped to, +ParamsWrapper+ will actually try to determine if there's
+  # a model related to it or not. This controller, for example:
+  #
+  #     class Admin::UsersController < ApplicationController
+  #     end
+  #
+  # will try to check if +Admin::User+ or +User+ model exists, and use it to
+  # determine the wrapper key respectively. If both of the model doesn't exists,
+  # it will then fallback to use +user+ as the key.
+  module ParamsWrapper
+    extend ActiveSupport::Concern
+
+    EXCLUDE_PARAMETERS = %w(authenticity_token _method utf8)
+
+    included do
+      class_attribute :_wrapper_options
+      self._wrapper_options = {:format => []}
+    end
+
+    module ClassMethods
+      # Sets the name of the wrapper key, or the model which +ParamsWrapper+
+      # would use to determine the attribute names from.
+      #
+      # ==== Examples
+      #   wrap_parameters :format => :xml
+      #     # enables the parmeter wrappes for XML format
+      #
+      #   wrap_parameters :person
+      #     # wraps parameters into +params[:person]+ hash
+      #
+      #   wrap_parameters Person
+      #     # wraps parameters by determine the wrapper key from Person class
+      #     (+person+, in this case) and the list of attribute names
+      #
+      #   wrap_parameters :only => [:username, :title]
+      #     # wraps only +:username+ and +:title+ attributes from parameters.
+      #
+      #   wrap_parameters false
+      #     # disable parameters wrapping for this controller altogether.
+      #
+      # ==== Options
+      # * <tt>:format</tt> - The list of formats in which the parameters wrapper
+      #   will be enabled.
+      # * <tt>:only</tt> - The list of attribute names which parmeters wrapper
+      #   will wrap into a nested hash.
+      # * <tt>:only</tt> - The list of attribute names which parmeters wrapper
+      #   will exclude from a nested hash.
+      def wrap_parameters(name_or_model_or_options, options = {})
+        if !name_or_model_or_options.is_a? Hash
+          if name_or_model_or_options != false
+            options = options.merge(:name_or_model => name_or_model_or_options)
+          else
+            options = opions.merge(:format => [])
+          end
+        else
+          options = name_or_model_or_options
+        end
+
+        options[:name_or_model] ||= _default_wrap_model
+        self._wrapper_options = self._wrapper_options.merge(options)
+      end
+
+      # Sets the default wrapper key or model which will be used to determine
+      # wrapper key and attribute names. Will be called automatically when the
+      # module is inherited.
+      def inherited(klass)
+        if klass._wrapper_options[:format].present?
+          klass._wrapper_options = klass._wrapper_options.merge(:name_or_model => klass._default_wrap_model)
+        end
+        super
+      end
+
+      # Determine the wrapper model from the controller's name. By convention,
+      # this could be done by trying to find the defined model that has the
+      # same singularize name as the controller. For example, +UsersController+
+      # will try to find if the +User+ model exists.
+      def _default_wrap_model
+        model_name = self.name.sub(/Controller$/, '').singularize
+
+        begin
+          model_klass = model_name.constantize
+        rescue NameError => e
+          unscoped_model_name = model_name.split("::", 2).last
+          break if unscoped_model_name == model_name
+          model_name = unscoped_model_name
+        end until model_klass
+
+        model_klass
+      end
+    end
+
+    # Performs parameters wrapping upon the request. Will be called automatically
+    # by the metal call stack.
+    def process_action(*args)
+      if _wrapper_enabled?
+        wrapped_hash = { _wrapper_key => request.request_parameters.slice(*_wrapped_keys) }
+        wrapped_filtered_hash = { _wrapper_key => request.filtered_parameters.slice(*_wrapped_keys) }
+
+        # This will make the wrapped hash accessible from controller and view
+        request.parameters.merge! wrapped_hash
+        request.request_parameters.merge! wrapped_hash
+
+        # This will make the wrapped hash displayed in the log file
+        request.filtered_parameters.merge! wrapped_filtered_hash
+      end
+      super
+    end
+
+    private
+      # Returns the wrapper key which will use to stored wrapped parameters.
+      def _wrapper_key
+        @_wrapper_key ||= if _wrapper_options[:name_or_model]
+            _wrapper_options[:name_or_model].to_s.demodulize.underscore
+          else
+            self.class.controller_name.singularize
+          end
+      end
+
+      # Returns the list of parameters which will be selected for wrapped.
+      def _wrapped_keys
+        @_wrapped_keys ||= if _wrapper_options[:only]
+            Array(_wrapper_options[:only]).collect(&:to_s)
+          elsif _wrapper_options[:except]
+            request.request_parameters.keys - Array(_wrapper_options[:except]).collect(&:to_s) - EXCLUDE_PARAMETERS
+          elsif _wrapper_options[:name_or_model].respond_to?(:column_names)
+            _wrapper_options[:name_or_model].column_names
+          else
+            request.request_parameters.keys - EXCLUDE_PARAMETERS
+          end
+      end
+
+      # Returns the list of enabled formats.
+      def _wrapper_formats
+        Array(_wrapper_options[:format])
+      end
+
+      # Checks if we should perform parameters wrapping.
+      def _wrapper_enabled?
+        _wrapper_formats.any?{ |format| format == request.content_mime_type.try(:ref) } && request.request_parameters[_wrapper_key].nil?
+      end
+  end
+end