Merge pull request #412 from avit/shared-context

Support merging searches using shared context

Author: jonatack

lib/ransack/adapters/active_record/3.0/context.rb

@@ -68,6 +68,22 @@ def type_for(attr)
           .type
         end
 
+        # All dependent JoinAssociation items used in the search query
+        #
+        def join_associations
+          @join_dependency.join_associations
+        end
+
+        def join_sources
+          raise NotImplementedError,
+          "ActiveRecord 3.0 does not use join_sources or support joining relations with Arel::Join nodes. Use join_associations."
+        end
+
+        def alias_tracker
+          raise NotImplementedError,
+          "ActiveRecord 3.0 does not have an alias tracker"
+        end
+
         private
 
         def get_parent_and_attribute_name(str, parent = @base)

lib/ransack/adapters/active_record/3.1/context.rb

@@ -73,6 +73,30 @@ def type_for(attr)
           @engine.connection_pool.columns_hash[table][name].type
         end
 
+        def join_associations
+          @join_dependency.join_associations
+        end
+
+        # All dependent Arel::Join nodes used in the search query
+        #
+        # This could otherwise be done as `@object.arel.join_sources`, except
+        # that ActiveRecord's build_joins sets up its own JoinDependency.
+        # This extracts what we need to access the joins using our existing
+        # JoinDependency to track table aliases.
+        #
+        def join_sources
+          base = Arel::SelectManager.new(@object.engine, @object.table)
+          joins = @object.joins_values
+          joins.each do |assoc|
+            assoc.join_to(base)
+          end
+          base.join_sources
+        end
+
+        def alias_tracker
+          @join_dependency.alias_tracker
+        end
+
         private
 
         def get_parent_and_attribute_name(str, parent = @base)

lib/ransack/adapters/active_record/context.rb

@@ -78,7 +78,55 @@ def klassify(obj)
           end
         end
 
-      private
+        if ::ActiveRecord::VERSION::STRING >= '4.1'
+
+          def join_associations
+            raise NotImplementedError,
+            "ActiveRecord 4.1 and later does not use join_associations. Use join_sources."
+          end
+
+          # All dependent Arel::Join nodes used in the search query
+          #
+          # This could otherwise be done as `@object.arel.join_sources`, except
+          # that ActiveRecord's build_joins sets up its own JoinDependency.
+          # This extracts what we need to access the joins using our existing
+          # JoinDependency to track table aliases.
+          #
+          def join_sources
+            base = Arel::SelectManager.new(@object.engine, @object.table)
+            joins = @join_dependency.join_constraints(@object.joins_values)
+            joins.each do |aliased_join|
+              base.from(aliased_join)
+            end
+            base.join_sources
+          end
+
+        else
+
+          # All dependent JoinAssociation items used in the search query
+          #
+          # Deprecated: this goes away in ActiveRecord 4.1. Use join_sources.
+          #
+          def join_associations
+            @join_dependency.join_associations
+          end
+
+          def join_sources
+            base = Arel::SelectManager.new(@object.engine, @object.table)
+            joins = @object.joins_values
+            joins.each do |assoc|
+              assoc.join_to(base)
+            end
+            base.join_sources
+          end
+
+        end
+
+        def alias_tracker
+          @join_dependency.alias_tracker
+        end
+
+        private
 
         def get_parent_and_attribute_name(str, parent = @base)
           attr_name = nil

lib/ransack/search.rb

@@ -17,7 +17,7 @@ def initialize(object, params = {}, options = {})
       params = {} unless params.is_a?(Hash)
       (params ||= {})
       .delete_if { |k, v| [*v].all? { |i| i.blank? && i != false } }
-      @context = Context.for(object, options)
+      @context = options[:context] || Context.for(object, options)
       @context.auth_object = options[:auth_object]
       @base = Nodes::Grouping.new(@context, options[:grouping] || 'and')
       @scope_args = {}

spec/ransack/adapters/active_record/context_spec.rb

@@ -6,6 +6,10 @@ module ActiveRecord
       describe Context do
         subject { Context.new(Person) }
 
+        if ::ActiveRecord::VERSION::STRING >= "3.1"
+          its(:alias_tracker) { should be_a ::ActiveRecord::Associations::AliasTracker }
+        end
+
         describe '#relation_for' do
           it 'returns relation for given object' do
             expect(subject.object).to be_an ::ActiveRecord::Relation
@@ -30,6 +34,45 @@ module ActiveRecord
           end
         end
 
+        describe "sharing context across searches" do
+          let(:shared_context) { Context.for(Person) }
+
+          before do
+            Search.new(Person, {:parent_name_eq => 'A'}, context: shared_context)
+            Search.new(Person, {:children_name_eq => 'B'}, context: shared_context)
+          end
+
+          describe '#join_associations', :if => ::ActiveRecord::VERSION::STRING <= '4.0' do
+            it 'returns dependent join associations for all searches run against the context' do
+              parents, children = shared_context.join_associations
+
+              expect(children.aliased_table_name).to eq "children_people"
+              expect(parents.aliased_table_name).to eq "parents_people"
+            end
+
+            it 'can be rejoined to execute a valid query' do
+              parents, children = shared_context.join_associations
+
+              expect { Person.joins(parents).joins(children).to_a }.to_not raise_error
+            end
+          end
+
+          describe '#join_sources', :if => ::ActiveRecord::VERSION::STRING >= '3.1' do
+            it 'returns dependent arel join nodes for all searches run against the context' do
+              parents, children = shared_context.join_sources
+
+              expect(children.left.name).to eq "children_people"
+              expect(parents.left.name).to eq "parents_people"
+            end
+
+            it 'can be rejoined to execute a valid query' do
+              parents, children = shared_context.join_sources
+
+              expect { Person.joins(parents).joins(children).to_a }.to_not raise_error
+            end
+          end
+        end
+
         it 'contextualizes strings to attributes' do
           attribute = subject.contextualize 'children_children_parent_name'
           expect(attribute).to be_a Arel::Attributes::Attribute

spec/ransack/search_spec.rb

@@ -40,6 +40,13 @@ module Ransack
       it 'does not raise exception for string :params argument' do
         expect { Search.new(Person, '') }.not_to raise_error
       end
+
+      it 'accepts a context option' do
+        shared_context = Context.for(Person)
+        search1 = Search.new(Person, {"name_eq" => "A"}, context: shared_context)
+        search2 = Search.new(Person, {"name_eq" => "B"}, context: shared_context)
+        expect(search1.context).to be search2.context
+      end
     end
 
     describe '#build' do