Add length predicates for string length search

lib/ransack/constants.rb

@@ -155,6 +155,31 @@ module Constants
         type: :boolean,
         validator: proc { |v| BOOLEAN_VALUES.include?(v) },
         formatter: proc { |v| nil } }
+      ],
+      ['length_eq'.freeze, {
+        arel_predicate: 'eq'.freeze,
+        type: :integer
+        }
+      ],
+      ['length_lt'.freeze, {
+        arel_predicate: 'lt'.freeze,
+        type: :integer
+        }
+      ],
+      ['length_lteq'.freeze, {
+        arel_predicate: 'lteq'.freeze,
+        type: :integer
+        }
+      ],
+      ['length_gt'.freeze, {
+        arel_predicate: 'gt'.freeze,
+        type: :integer
+        }
+      ],
+      ['length_gteq'.freeze, {
+        arel_predicate: 'gteq'.freeze,
+        type: :integer
+        }
       ]
     ].freeze
 

lib/ransack/nodes/condition.rb

@@ -343,14 +343,20 @@ def combinator_method
       def format_predicate(attribute)
         arel_pred = arel_predicate_for_attribute(attribute)
         arel_values = formatted_values_for_attribute(attribute)
-        
+
         # For LIKE predicates, wrap the value in Arel::Nodes.build_quoted to prevent
         # ActiveRecord normalization from affecting wildcard patterns
         if like_predicate?(arel_pred)
           arel_values = Arel::Nodes.build_quoted(arel_values)
         end
-
-        predicate = attr_value_for_attribute(attribute).public_send(arel_pred, arel_values)
+
+        attr_value = if length_predicate?
+          length_function_for_attribute(attribute)
+        else
+          attr_value_for_attribute(attribute)
+        end
+
+        predicate = attr_value.public_send(arel_pred, arel_values)
 
         if in_predicate?(predicate)
           predicate.right = predicate.right.map do |pr|
@@ -391,6 +397,27 @@ def replace_right_node?(predicate)
         attribute_type == :integer && arel_node.value.is_a?(Integer)
       end
 
+      def length_predicate?
+        predicate_name.to_s.start_with?('length_')
+      end
+
+      def length_function_for_attribute(attribute)
+        adapter_name = ActiveRecord::Base.connection.adapter_name
+        function_name = case adapter_name
+        when "PostGIS".freeze, "PostgreSQL".freeze
+          "CHAR_LENGTH".freeze
+        when "Mysql2".freeze
+          "CHAR_LENGTH".freeze
+        else
+          "LENGTH".freeze
+        end
+
+        Arel::Nodes::NamedFunction.new(
+          function_name,
+          [attr_value_for_attribute(attribute)]
+        )
+      end
+
       def valid_combinator?
         attributes.size < 2 || Constants::AND_OR.include?(combinator)
       end

spec/ransack/predicate_spec.rb

@@ -461,6 +461,91 @@ module Ransack
       end
     end
 
+    describe 'length_eq' do
+      it 'generates a LENGTH(column) = value condition' do
+        @s.name_length_eq = 4
+        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) = 4/
+      end
+
+      it 'does not generate a condition for nil' do
+        @s.name_length_eq = nil
+        expect(@s.result.to_sql).not_to match /WHERE/
+      end
+
+      it "works with attribute names containing 'length'" do
+        @s.length_field_length_eq = 8
+        field = "#{quote_table_name("people")}.#{quote_column_name("length_field")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) = 8/
+      end
+    end
+
+    describe 'length_lt' do
+      it 'generates a LENGTH(column) < value condition' do
+        @s.name_length_lt = 5
+        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) < 5/
+      end
+
+      it 'does not generate a condition for nil' do
+        @s.name_length_lt = nil
+        expect(@s.result.to_sql).not_to match /WHERE/
+      end
+    end
+
+    describe 'length_lteq' do
+      it 'generates a LENGTH(column) <= value condition' do
+        @s.name_length_lteq = 4
+        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) <= 4/
+      end
+
+      it 'does not generate a condition for nil' do
+        @s.name_length_lteq = nil
+        expect(@s.result.to_sql).not_to match /WHERE/
+      end
+
+      it "works with attribute names containing 'length'" do
+        @s.length_field_length_lteq = 10
+        field = "#{quote_table_name("people")}.#{quote_column_name("length_field")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) <= 10/
+      end
+
+      it "works with attribute names starting with 'length'" do
+        @s.length_of_name_length_lteq = 5
+        field = "#{quote_table_name("people")}.#{quote_column_name("length_of_name")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) <= 5/
+      end
+    end
+
+    describe 'length_gt' do
+      it 'generates a LENGTH(column) > value condition' do
+        # Use email instead of name to avoid conflict with name_length column
+        @s.email_length_gt = 10
+        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) > 10/
+      end
+
+      it 'does not generate a condition for nil' do
+        @s.email_length_gt = nil
+        expect(@s.result.to_sql).not_to match /WHERE/
+      end
+    end
+
+    describe 'length_gteq' do
+      it 'generates a LENGTH(column) >= value condition' do
+        # Use email instead of name to avoid conflict with name_length column
+        @s.email_length_gteq = 10
+        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
+        expect(@s.result.to_sql).to match /(CHAR_LENGTH|LENGTH)\(#{field}\) >= 10/
+      end
+
+      it 'does not generate a condition for nil' do
+        @s.email_length_gteq = nil
+        expect(@s.result.to_sql).not_to match /WHERE/
+      end
+    end
+
     context "defining custom predicates" do
       describe "with 'not_in' arel predicate" do
         before do