Feature/action contracts

lib/hanami/action.rb

@@ -39,7 +39,7 @@ def self.gem_loader
         loader.ignore(
           "#{root}/hanami-controller.rb",
           "#{root}/hanami/controller/version.rb",
-          "#{root}/hanami/action/{constants,errors,params,validatable}.rb"
+          "#{root}/hanami/action/{constants,errors,params,contract,validatable}.rb"
         )
         loader.inflector.inflect("csrf_protection" => "CSRFProtection")
       end
@@ -138,6 +138,19 @@ def self.params(_klass = nil)
             "To use `params`, please add 'hanami/validations' gem to your Gemfile"
     end
 
+    # Placeholder implementation for contract class method
+    #
+    # Raises a developer friendly error to include `hanami/validations`.
+    #
+    # @raise [NoMethodError]
+    #
+    # @api public
+    # @since 2.2.0
+    def self.contract
+      raise NoMethodError,
+            "To use `contract`, please add 'hanami/validations' gem to your Gemfile"
+    end
+
     # @overload self.append_before(*callbacks, &block)
     #   Define a callback for an Action.
     #   The callback will be executed **before** the action is called, in the
@@ -305,8 +318,8 @@ def call(env)
       response = nil
 
       halted = catch :halt do
-        params   = self.class.params_class.new(env)
-        request  = build_request(
+        params = self.class.params_class.new(env)
+        request = build_request(
           env: env,
           params: params,
           session_enabled: session_enabled?

lib/hanami/action/base_params.rb

@@ -19,18 +19,13 @@ class Action
     # @api private
     # @since 0.7.0
     class BaseParams
+      include Hanami::Action::RequestParams::Base
       # @attr_reader env [Hash] the Rack env
       #
       # @since 0.7.0
       # @api private
       attr_reader :env
 
-      # @attr_reader raw [Hash] the raw params from the request
-      #
-      # @since 0.7.0
-      # @api private
-      attr_reader :raw
-
       # Returns a new frozen params object for the Rack env.
       #
       # @param env [Hash] a Rack env or an hash of params.
@@ -39,23 +34,11 @@ class BaseParams
       # @api private
       def initialize(env)
         @env    = env
-        @raw    = _extract_params
-        @params = Utils::Hash.deep_symbolize(@raw)
+        @input  = Hanami::Action::ParamsExtraction.new(env).call
+        @params = Utils::Hash.deep_symbolize(@input)
         freeze
       end
 
-      # Returns the value for the given params key.
-      #
-      # @param key [Symbol] the key
-      #
-      # @return [Object,nil] the associated value, if found
-      #
-      # @since 0.7.0
-      # @api public
-      def [](key)
-        @params[key]
-      end
-
       # Returns an value associated with the given params key.
       #
       # You can access nested attributes by listing all the keys in the path. This uses the same key
@@ -86,17 +69,6 @@ def [](key)
       #     end
       #   end
       #
-      # @since 0.7.0
-      # @api public
-      def get(*keys)
-        @params.dig(*keys)
-      end
-
-      # This is for compatibility with Hanami::Helpers::FormHelper::Values
-      #
-      # @api private
-      # @since 0.8.0
-      alias_method :dig, :get
 
       # Returns true at all times, providing a common interface with {Params}.
       #
@@ -110,50 +82,8 @@ def valid?
         true
       end
 
-      # Returns a hash of the parsed request params.
-      #
-      # @return [Hash]
-      #
-      # @since 0.7.0
-      # @api public
-      def to_h
-        @params
-      end
-      alias_method :to_hash, :to_h
-
-      # Iterates over the params.
-      #
-      # Calls the given block with each param key-value pair; returns the full hash of params.
-      #
-      # @yieldparam key [Symbol]
-      # @yieldparam value [Object]
-      #
-      # @return [to_h]
-      #
-      # @since 0.7.1
-      # @api public
-      def each(&blk)
-        to_h.each(&blk)
-      end
-
       private
 
-      # @since 0.7.0
-      # @api private
-      def _extract_params
-        result = {}
-
-        if env.key?(Action::RACK_INPUT)
-          result.merge! ::Rack::Request.new(env).params
-          result.merge! _router_params
-        else
-          result.merge! _router_params(env)
-          env[Action::REQUEST_METHOD] ||= Action::DEFAULT_REQUEST_METHOD
-        end
-
-        result
-      end
-
       # @since 0.7.0
       # @api private
       def _router_params(fallback = {})

lib/hanami/action/contract.rb

@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module Hanami
+  class Action
+    # A wrapper for defining validation rules using Dry::Validation. This class essentially
+    # wraps a Dry::Validation::Contract and acts as a proxy to actually use Dry gem
+    #
+    # Defined via the `contract` block in an action class.
+    # Although more complex domain-specific validations, or validations concerned with things such as uniqueness
+    # are usually better performed at layers deeper than your HTTP actions, Contract still provides helpful features
+    # that you can use without contravening the advice form above.
+    #
+    # @since 2.2.0
+    class Contract
+      include Hanami::Action::RequestParams::ActionValidations
+      include Hanami::Action::RequestParams::Base
+      # A wrapper for the result of a contract validation
+      # @since 2.2.0
+      # @api private
+      class Result < SimpleDelegator
+        # @since 2.0.0
+        # @api private
+        def to_h
+          __getobj__.to_h
+        end
+
+        # This method is called messages not errors to be consistent with the Hanami::Validations::Result
+        #
+        # @return [Hash] the error messages
+        #
+        # @since 2.0.0
+        # @api private
+        def messages
+          __getobj__.errors.to_h
+        end
+      end
+
+      # Define a contract for the given action
+      #
+      # @param blk [Proc] the block to define the contract, including [Params] as a contract schema and connected rules
+      #
+      # @since 2.2.0
+      # @api private
+      #
+      # @example
+      # class Create < Hanami::Action
+      #   contract do
+      #     params do
+      #       required(:birth_date).value(:date)
+      #     end
+      #     rule(:birth_date) do
+      #       key.failure('you must be 18 years or older to register') if value > Date.today - 18.years
+      #     end
+      #   end
+      #
+      #   def handle(req, *)
+      #     halt 400 unless req.contract.call.errors.empty?
+      #     # ...
+      #   end
+      # end
+      def self.contract(&blk)
+        @_validator = Dry::Validation::Contract.build(&blk)
+      end
+
+      # @since 2.2.0
+      # @api private
+      class << self
+        attr_reader :_validator
+      end
+
+      private
+
+      # @since 2.2.0
+      def validate
+        Result.new(
+          self.class._validator.call(@input)
+        )
+      end
+    end
+  end
+end