Add before_validation hooks to resources

Author: Abderrahmane Boudi

lib/graphiti/resource.rb

@@ -112,6 +112,13 @@ def resolve(scope)
       adapter.resolve(scope)
     end
 
+    def before_validation(model, metadata)
+      hooks = self.class.config[:before_validation][metadata[:method]] || []
+      hooks.each do |hook|
+        instance_exec(model, metadata, &hook)
+      end
+    end
+
     def before_commit(model, metadata)
       hooks = self.class.config[:before_commit][metadata[:method]] || []
       hooks.each do |hook|

lib/graphiti/resource/configuration.rb

@@ -186,6 +186,7 @@ def config
               sort_all: nil,
               sorts: {},
               pagination: nil,
+              before_validation: {},
               before_commit: {},
               after_commit: {},
               attributes: {},

lib/graphiti/resource/dsl.rb

@@ -81,6 +81,13 @@ def default_filter(name = nil, &blk)
           }
         end
 
+        def before_validation(only: [:create, :update, :destroy], &blk)
+          Array(only).each do |verb|
+            config[:before_validation][verb] ||= []
+            config[:before_validation][verb] << blk
+          end
+        end
+
         def before_commit(only: [:create, :update, :destroy], &blk)
           Array(only).each do |verb|
             config[:before_commit][verb] ||= []

lib/graphiti/resource_proxy.rb

@@ -124,6 +124,8 @@ def destroy
         validator = ::Graphiti::Util::ValidationResponse.new \
           model, @payload
         validator.validate!
+        # FIXME: I don't know in which scenarios the following line is needed!
+        # @resource.before_validation(model, metadata)
         @resource.before_commit(model, metadata)
 
         {result: validator}

lib/graphiti/util/persistence.rb

@@ -60,6 +60,8 @@ def run
 
     post_process(persisted, parents)
     post_process(persisted, children)
+    before_validation = -> { @resource.before_validation(persisted, metadata) }
+    add_hook(before_validation, :before_validation)
     before_commit = -> { @resource.before_commit(persisted, metadata) }
     add_hook(before_commit, :before_commit)
     after_commit = -> { @resource.after_commit(persisted, metadata) }

lib/graphiti/util/transaction_hooks_recorder.rb

@@ -8,6 +8,7 @@ class TransactionHooksRecorder
       #
       # ```ruby
       # TransactionHooksRecorder.record do
+      #   TransactionHooksRecorder.add(->{ do_some_stuff() }, :before_validation)
       #   TransactionHooksRecorder.add(->{ do_stuff() }, :before_commit)
       #   TransactionHooksRecorder.add(->{ do_more_stuff() }, :after_commit)
       #   {
@@ -27,6 +28,7 @@ def record
 
           begin
             result = yield
+            run(:before_validation)
             run(:before_commit)
 
             unless result.is_a?(::Hash)
@@ -59,6 +61,7 @@ def _hooks
 
         def reset_hooks
           Thread.current[:_graphiti_hooks] = {
+            before_validation: [],
             before_commit: [],
             after_commit: [],
           }

spec/integration/rails/transaction_hooks_spec.rb

@@ -1,7 +1,7 @@
 # rubocop: disable Style/GlobalVars
 
 if ENV["APPRAISAL_INITIALIZED"]
-  RSpec.describe "before_ & after_commit hooks", type: :controller do
+  RSpec.describe "before_validation, before_ & after_commit hooks", type: :controller do
     class Callbacks
       class << self
         attr_accessor :fired, :in_transaction_during, :entities
@@ -27,6 +27,7 @@ def in_transaction?
       Callbacks.fired = {}
       Callbacks.in_transaction_during = {}
       Callbacks.entities = []
+      $raise_on_before_validation = {employee: false}
       $raise_on_before_commit = {employee: true}
     end
 
@@ -63,7 +64,7 @@ class PositionResource < ApplicationResource
         before_commit do |position|
           Callbacks.add(:before_position, position)
           if $raise_on_before_commit[:position]
-            raise "rollitback_book"
+            raise "rollitback_position"
           end
         end
 
@@ -75,6 +76,13 @@ class EmployeeResource < ApplicationResource
 
         attribute :first_name, :string
 
+        before_validation do |employee|
+          Callbacks.add(:before_validation, employee)
+          if $raise_on_before_validation[:employee]
+            raise "rollitback"
+          end
+        end
+
         before_commit only: [:create] do |employee|
           Callbacks.add(:before_create, employee)
           if $raise_on_before_commit[:employee]
@@ -191,7 +199,7 @@ def json
           post :create, params: payload
         }.to raise_error("rollitback")
         expect(Employee.count).to be_zero
-        expect(Callbacks.entities.length).to eq(1)
+        expect(Callbacks.entities.length).to eq(2)
         expect(Callbacks.fired[:before_create]).to be_a(Employee)
       end
 
@@ -230,13 +238,31 @@ def json
         it "fires all before and after_commit hooks" do
           post :create, params: payload
           expect(Callbacks.entities).to eq([
+            :before_validation,
             :before_create,
             :stacked_before_create,
             :employee_after_create,
             :employee_after_create_eval_test,
           ])
         end
       end
+
+      context "when an error is raised before_validation" do
+        before do
+          $raise_on_before_validation = {employee: true}
+        end
+
+        it "does not run before_commit callbacks" do
+          expect_any_instance_of(Graphiti::Util::ValidationResponse)
+            .to receive(:validate!)
+          expect {
+            post :create, params: payload
+          }.to raise_error("rollitback")
+          expect(Employee.count).to be_zero
+          expect(Callbacks.entities.length).to eq(1)
+          expect(Callbacks.fired[:before_validation]).to be_a(Employee)
+        end
+      end
     end
 
     context "nested" do
@@ -281,6 +307,7 @@ def json
         post :create, params: payload
 
         expect(Callbacks.entities).to eq([
+          :before_validation,
           :before_create,
           :stacked_before_create,
           :before_position,
@@ -309,6 +336,12 @@ def json
         expect(Callbacks.in_transaction_during[:employee_after_create]).to eq false
         expect(Callbacks.fired[:employee_after_create_eval_test]).to be_a(IntegrationHooks::EmployeeResource)
       end
+
+      it "can access children resources from before_validation" do
+        post :create, params: payload
+        expect(Callbacks.fired[:employee_after_create].positions.length).to eq(1)
+        expect(Callbacks.fired[:employee_after_create].positions[0]).to be_a(Position)
+      end
     end
 
     context "when yielding meta" do