Strategy to inject dependencies via class- and instance-methods

lib/dry/auto_inject/strategies.rb

@@ -19,3 +19,4 @@ def self.register_default(name, strategy)
 require 'dry/auto_inject/strategies/args'
 require 'dry/auto_inject/strategies/hash'
 require 'dry/auto_inject/strategies/kwargs'
+require 'dry/auto_inject/strategies/methods'

lib/dry/auto_inject/strategies/base.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Dry
+  module AutoInject
+    class Strategies
+      # @api private
+      class Base < Module
+        ClassMethods = Class.new(Module)
+        InstanceMethods = Class.new(Module)
+
+        attr_reader :container
+        attr_reader :dependency_map
+        attr_reader :instance_mod
+        attr_reader :class_mod
+
+        def initialize(container, *dependency_names)
+          @container = container
+          @dependency_map = DependencyMap.new(*dependency_names)
+          @instance_mod = InstanceMethods.new
+          @class_mod = ClassMethods.new
+        end
+
+        # @api private
+        def included(klass)
+          klass.send(:include, instance_mod)
+          klass.extend(class_mod)
+
+          super
+        end
+      end
+    end
+  end
+end

lib/dry/auto_inject/strategies/constructor.rb

@@ -1,36 +1,19 @@
 # frozen_string_literal: true
 
+require 'dry/auto_inject/strategies/base'
 require 'dry/auto_inject/dependency_map'
 
 module Dry
   module AutoInject
     class Strategies
-      class Constructor < Module
-        ClassMethods = Class.new(Module)
-        InstanceMethods = Class.new(Module)
-
-        attr_reader :container
-        attr_reader :dependency_map
-        attr_reader :instance_mod
-        attr_reader :class_mod
-
-        def initialize(container, *dependency_names)
-          @container = container
-          @dependency_map = DependencyMap.new(*dependency_names)
-          @instance_mod = InstanceMethods.new
-          @class_mod = ClassMethods.new
-        end
-
+      class Constructor < Base
         # @api private
         def included(klass)
           define_readers
 
           define_new
           define_initialize(klass)
 
-          klass.send(:include, instance_mod)
-          klass.extend(class_mod)
-
           super
         end
 

lib/dry/auto_inject/strategies/methods.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require 'dry/auto_inject/strategies/base'
+require 'dry/auto_inject/method_parameters'
+
+module Dry
+  module AutoInject
+    class Strategies
+      # @api private
+      class Methods < Base
+        # @api private
+        def included(klass)
+          define_class_methods
+          define_instance_methods
+
+          super
+        end
+
+        private
+
+        def define_class_methods
+          class_mod.class_exec(container, dependency_map) do |container, dependency_map|
+            dependency_map.to_h.each do |name, identifier|
+              define_method name do
+                container[identifier]
+              end
+            end
+
+            def with_deps(**deps)
+              Class.new(self) do |klass|
+                deps.each do |name, value|
+                  singleton_class.define_method name do
+                    value
+                  end
+                end
+              end
+            end
+          end
+
+          self
+        end
+
+        def define_instance_methods
+          instance_mod.class_exec(container, dependency_map) do |container, dependency_map|
+            dependency_map.to_h.each do |name, identifier|
+              define_method name do
+                self.class.send(name)
+              end
+            end
+          end
+
+          self
+        end
+      end
+
+      register :methods, Methods
+    end
+  end
+end

spec/integration/methods_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+RSpec.describe 'methods' do
+  it 'defines methods returning dependencies' do
+    module Test
+      AutoInject = Dry::AutoInject(one: 'dep 1', two: 'dep 2').methods
+    end
+
+    obj = Class.new do
+      include Test::AutoInject[:one, :two]
+    end
+
+    expect(obj.one).to eq 'dep 1'
+    expect(obj.new.one).to eq 'dep 1'
+    expect(obj.two).to eq 'dep 2'
+    expect(obj.new.two).to eq 'dep 2'
+
+    other_obj = obj.with_deps(one: 'other dep 1')
+    expect(other_obj.one).to eq 'other dep 1'
+    expect(other_obj.new.one).to eq 'other dep 1'
+    expect(other_obj.two).to eq 'dep 2'
+    expect(other_obj.new.two).to eq 'dep 2'
+  end
+end