Allow to specify custom scoping for included associations

CHANGELOG.md

@@ -37,6 +37,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
  - Print reason of association exclusion or inclusion in verbose mode. [@Envek]
 
+ - Allow to apply custom scoping to included associations. [@Envek]
+
+   ```ruby
+   config.root('Forum', featured: true) do |forum|
+     forum.include('questions.answers') do
+       order(created_at: :desc)
+     end
+   end
+   ```
+
 ### Fixed
 
  - Bug with null foreign key to back to auxiliary `has_one` association with not matching names. E.g. user has many profiles and has one default profile, profile belongs to user.

README.md

@@ -48,6 +48,11 @@ EvilSeed.configure do |config|
   # First, you should specify +root models+ and their +constraints+ to limit the number of dumped records:
   # This is like Forum.where(featured: true).all
   config.root('Forum', featured: true) do |root|
+    # You can limit number of records to be dumped
+    root.limit(100)
+    # Specify order for records to be selected for dump
+    root.order(created_at: :desc)
+
     # It's possible to remove some associations from dumping with pattern of association path to exclude
     #
     # Association path is a dot-delimited string of association chain starting from model itself:
@@ -59,6 +64,11 @@ EvilSeed.configure do |config|
     # which is the same as
     root.include(/\Aforum(\.parent(\.questions(\.(answers|votes))?)?)?\z/)
 
+    # You can also specify custom scoping for associations
+    root.include(questions: { answers: :reactions }) do
+      order(created_at: :desc) # Any ActiveRecord query method is allowed
+    end
+
     # It's possible to limit the number of included into dump has_many and has_one records for every association
     # Note that belongs_to records for all not excluded associations are always dumped to keep referential integrity.
     root.limit_associations_size(100)

lib/evil_seed/configuration/root.rb

@@ -4,7 +4,7 @@ module EvilSeed
   class Configuration
     # Configuration for dumping some root model and its associations
     class Root
-      attr_reader :model, :constraints
+      attr_reader :model, :constraints, :limit, :order
       attr_reader :total_limit, :association_limits, :deep_limit, :dont_nullify
       attr_reader :exclusions, :inclusions
 
@@ -14,7 +14,7 @@ def initialize(model, dont_nullify, *constraints)
         @model = model
         @constraints = constraints
         @exclusions = []
-        @inclusions = []
+        @inclusions = {}
         @association_limits = {}
         @deep_limit = nil
         @dont_nullify = dont_nullify
@@ -36,14 +36,16 @@ def exclude(*association_patterns)
 
       # Include some excluded associations back to the dump
       # @param association_patterns Array<String, Regex> Patterns to exclude associated models from dump
-      def include(*association_patterns)
+      def include(*association_patterns, &block)
         association_patterns.each do |pattern|
           case pattern
           when String, Regexp
-            @inclusions << pattern
+            @inclusions[pattern] = block
           else
             path_prefix = model.constantize.model_name.singular
-            @inclusions += compile_patterns(pattern, prefix: path_prefix).map { |p| Regexp.new(/\A#{p}\z/) }
+            compile_patterns(pattern, prefix: path_prefix).map do |p|
+              @inclusions[Regexp.new(/\A#{p}\z/)] = block
+            end
           end
         end
       end
@@ -56,6 +58,18 @@ def exclude_optional_belongs_to
         @excluded_optional_belongs_to = :exclude_optional_belongs_to
       end
 
+      def limit(limit = nil)
+        return @limit if limit.nil?
+
+        @limit = limit
+      end
+
+      def order(order = nil)
+        return @order if order.nil?
+
+        @order = order
+      end
+
       # Limit number of records in all (if pattern is not provided) or given  associations to include into dump
       # @param limit               [Integer]       Maximum number of records in associations to include into dump
       # @param association_pattern [String, Regex] Pattern to limit number of records for certain associated models
@@ -82,7 +96,7 @@ def excluded?(association_path)
       end
 
       def included?(association_path)
-        inclusions.find { |inclusion| association_path.match(inclusion) } #.match(association_path) }
+        inclusions.find { |inclusion, _block| association_path.match(inclusion) }
       end
 
       def excluded_has_relations?

lib/evil_seed/relation_dumper.rb

@@ -26,7 +26,7 @@ class RelationDumper
     attr_reader :relation, :root_dumper, :model_class, :association_path, :search_key, :identifiers, :nullify_columns,
                 :belongs_to_reflections, :has_many_reflections, :foreign_keys, :loaded_ids, :to_load_map,
                 :record_dumper, :inverse_reflection, :table_names, :options,
-                :current_deep, :verbose
+                :current_deep, :verbose, :custom_scope
 
     delegate :root, :configuration, :dont_nullify, :total_limit, :deep_limit, :loaded_map, to: :root_dumper
 
@@ -52,6 +52,7 @@ def initialize(relation, root_dumper, association_path, **options)
       @options                = options
       @current_deep           = association_path.split('.').size
       @dont_nullify           = dont_nullify
+      @custom_scope           = options[:custom_scope]
     end
 
     # Generate dump and write it into +io+
@@ -73,7 +74,15 @@ def dump!
       original_ignored_columns = model_class.ignored_columns
       model_class.ignored_columns += Array(configuration.ignored_columns_for(model_class.sti_name))
       model_class.send(:reload_schema_from_cache) if ActiveRecord.version < Gem::Version.new("6.1.0.rc1") # See https://github.com/rails/rails/pull/37581
-      if identifiers.present?
+      if custom_scope
+        puts("  # #{search_key} (with scope)") if verbose
+        attrs = fetch_attributes(relation)
+        puts(" -- dumped #{attrs.size}") if verbose
+        attrs.each do |attributes|
+          next unless check_limits!
+          dump_record!(attributes)
+        end
+      elsif identifiers.present?
         puts("  # #{search_key} => #{identifiers}") if verbose
         # Don't use AR::Base#find_each as we will get error on Oracle if we will have more than 1000 ids in IN statement
         identifiers.in_groups_of(MAX_IDENTIFIERS_IN_IN_STMT).each do |ids|
@@ -129,16 +138,17 @@ def dump_belongs_to_associations!
     end
 
     def dump_has_many_associations!
-      has_many_reflections.map do |reflection|
+      has_many_reflections.map do |reflection, custom_scope|
         next if loaded_ids.empty? || total_limit.try(:zero?)
         RelationDumper.new(
-          build_relation(reflection),
+          build_relation(reflection, custom_scope),
           root_dumper,
           "#{association_path}.#{reflection.name}",
           search_key:       reflection.foreign_key,
           identifiers:      loaded_ids,
           inverse_of:       reflection.inverse_of.try(:name),
           limitable:        true,
+          custom_scope:     custom_scope,
         ).call
       end
     end
@@ -157,13 +167,14 @@ def check_limits!
       root_dumper.check_limits!(association_path)
     end
 
-    def build_relation(reflection)
+    def build_relation(reflection, custom_scope = nil)
       if configuration.unscoped
         relation = reflection.klass.unscoped
       else
         relation = reflection.klass.all
       end
       relation = relation.instance_eval(&reflection.scope) if reflection.scope
+      relation = relation.instance_eval(&custom_scope) if custom_scope
       relation = relation.where(reflection.type => model_class.to_s) if reflection.options[:as] # polymorphic
       relation
     end
@@ -205,7 +216,9 @@ def setup_has_many_reflections
         excluded ||= root.excluded?("#{association_path}.#{reflection.name}")
         puts " -- #{reflection.macro} #{reflection.name} #{"excluded by #{excluded}" if excluded} #{"re-included by #{included}" if included}" if verbose
         !(excluded and not included)
-      end.map(&:second)
+      end.map do |_reflection_name, reflection|
+        [reflection, root.included?("#{association_path}.#{reflection.name}")&.last]
+      end
     end
   end
 end

lib/evil_seed/root_dumper.rb

@@ -28,6 +28,8 @@ def call
       relation = model_class.all
       relation = relation.unscoped if configuration.unscoped
       relation = relation.where(*root.constraints) if root.constraints.any? # without arguments returns not a relation
+      relation = relation.limit(root.limit) if root.limit
+      relation = relation.order(root.order) if root.order
       RelationDumper.new(relation, self, association_path).call
     end
 

test/db/models.rb

@@ -8,6 +8,7 @@ class User < ActiveRecord::Base
   has_many :questions, foreign_key: :author_id
   has_many :answers,   foreign_key: :author_id
   has_many :votes
+  has_many :reactions
 
   has_and_belongs_to_many :roles, join_table: :user_roles
 end
@@ -38,6 +39,7 @@ class Question < ActiveRecord::Base
 
   has_many :answers
   has_many :votes, as: :votable
+  has_many :reactions, as: :reactable
 
   has_many :voters, through: :votes, source: :user
 
@@ -48,6 +50,7 @@ class Answer < ActiveRecord::Base
   belongs_to :author, class_name: 'User'
 
   has_many :votes, as: :votable
+  has_many :reactions, as: :reactable
 
   has_many :voters, through: :votes, source: :user
 
@@ -62,3 +65,8 @@ class Vote < ActiveRecord::Base
   belongs_to :votable, polymorphic: true
   belongs_to :user
 end
+
+class Reaction < ActiveRecord::Base
+  belongs_to :votable, polymorphic: true
+  belongs_to :user
+end

test/db/schema.rb

@@ -55,6 +55,13 @@ def create_schema!
       t.references :user, foreign_key: { on_delete: :nullify }
     end
 
+    create_table :reactions do |t|
+      t.references :reactable, polymorphic: true
+      t.references :user, foreign_key: { on_delete: :nullify }
+      t.string :reaction
+      t.timestamps null: false
+    end
+
     create_table :roles do |t|
       t.string :name
       t.string :permissions, **(ENV["DB"] == "postgresql" ? { array: true } : {})

test/db/seeds.rb

@@ -32,12 +32,16 @@
 
 question.votes.create!(user: User.find_by!(login: 'alice'))
 
-question.answers.create!(
+answer = question.answers.create!(
   text:   'Oh please go on hack it, ROFL)))',
   best:   true,
   author: User.find_by!(login: 'alice'),
 )
 
+answer.reactions.create!(users.map.with_index do |user, i|
+  { user: user, reaction: ':+1:', created_at: Time.current - 1.hour + i.minutes }
+end)
+
 answer = question.answers.create!(
   text:   'Please, stop',
   author: User.find_by!(login: 'bob'),

test/evil_seed/dumper_test.rb

@@ -11,6 +11,7 @@ def test_it_dumps_tree_structures_with_foreign_keys
         root.exclude('forum.users')
         root.exclude(/parent\.users/)
         root.exclude(/role\..+/)
+        root.exclude(/\.reactions\b/)
       end
       configuration.customize('User') do |attributes|
         attributes['password'] = '12345678'
@@ -77,5 +78,24 @@ def test_it_applies_unscoping_and_inclusions
       assert_match(/'Descendant forum'/, result)
       assert_match(/'Oops, I was wrong'/, result)
     end
+
+    def test_it_applies_custom_scopes
+      configuration = EvilSeed::Configuration.new
+      configuration.root('Forum', name: 'Descendant forum') do |root|
+        root.include(parent: {questions: :answers })
+        root.include("forum.parent.questions.answers.reactions") do
+          order(created_at: :desc).limit(2)
+        end
+        root.exclude(/.\..+/)
+      end
+
+      io = StringIO.new
+      EvilSeed::Dumper.new(configuration).call(io)
+      result = io.string
+      File.write(File.join('tmp', "#{__method__}.sql"), result)
+      assert io.closed?
+      assert_match("':+1:'", result)
+      assert_equal(2, result.scan("':+1:'").size)
+    end
   end
 end

test/evil_seed_test.rb

@@ -11,6 +11,7 @@ def setup
         root.exclude(/parent\.users/)
         root.exclude(/role\..+/)
         root.exclude(/\.profiles/)
+        root.exclude(/\.reactions\b/)
       end
       config.root('Question') do |root|
         root.exclude(/.*/)