Merge pull request #1048 from fatkodima/copy-command

[Redis 6.2] Add COPY command

lib/redis.rb

@@ -656,6 +656,41 @@ def move(key, db)
     end
   end
 
+  # Copy a value from one key to another.
+  #
+  # @example Copy a value to another key
+  #   redis.set "foo", "value"
+  #     # => "OK"
+  #   redis.copy "foo", "bar"
+  #     # => true
+  #   redis.get "bar"
+  #     # => "value"
+  #
+  # @example Copy a value to a key in another database
+  #   redis.set "foo", "value"
+  #     # => "OK"
+  #   redis.copy "foo", "bar", db: 2
+  #     # => true
+  #   redis.select 2
+  #     # => "OK"
+  #   redis.get "bar"
+  #     # => "value"
+  #
+  # @param [String] source
+  # @param [String] destination
+  # @param [Integer] db
+  # @param [Boolean] replace removes the `destination` key before copying value to it
+  # @return [Boolean] whether the key was copied or not
+  def copy(source, destination, db: nil, replace: false)
+    command = [:copy, source, destination]
+    command << "DB" << db if db
+    command << "REPLACE" if replace
+
+    synchronize do |client|
+      client.call(command, &Boolify)
+    end
+  end
+
   def object(*args)
     synchronize do |client|
       client.call([:object] + args)

lib/redis/distributed.rb

@@ -215,6 +215,13 @@ def move(key, db)
       node_for(key).move(key, db)
     end
 
+    # Copy a value from one key to another.
+    def copy(source, destination, **options)
+      ensure_same_node(:copy, [source, destination]) do |node|
+        node.copy(source, destination, **options)
+      end
+    end
+
     # Return a random key from the keyspace.
     def randomkey
       raise CannotDistribute, :randomkey

test/cluster_commands_on_value_types_test.rb

@@ -11,4 +11,8 @@ class TestClusterCommandsOnValueTypes < Minitest::Test
   def test_move
     assert_raises(Redis::CommandError) { super }
   end
+
+  def test_copy
+    assert_raises(Redis::CommandError) { super }
+  end
 end

test/distributed_commands_on_value_types_test.rb

@@ -127,4 +127,12 @@ def test_migrate
       r.migrate("foo", {})
     end
   end
+
+  def test_copy
+    r.set("foo", "s1")
+
+    assert_raises Redis::Distributed::CannotDistribute do
+      r.copy("foo", "bar")
+    end
+  end
 end

test/helper.rb

@@ -158,6 +158,11 @@ def target_version(target)
       end
     end
 
+    def with_db(index)
+      r.select(index)
+      yield
+    end
+
     def omit_version(min_ver)
       skip("Requires Redis > #{min_ver}") if version < min_ver
     end

test/lint/value_types.rb

@@ -162,5 +162,41 @@ def test_move
       assert_equal "s1", r.get("foo")
       assert_equal "s3", r.get("bar")
     end
+
+    def test_copy
+      target_version("6.2") do
+        with_db(14) do
+          r.flushdb
+
+          r.set "foo", "s1"
+          r.set "bar", "s2"
+
+          assert r.copy("foo", "baz")
+          assert_equal "s1", r.get("baz")
+
+          assert !r.copy("foo", "bar")
+          assert r.copy("foo", "bar", replace: true)
+          assert_equal "s1", r.get("bar")
+        end
+
+        with_db(15) do
+          r.set "foo", "s3"
+          r.set "bar", "s4"
+        end
+
+        with_db(14) do
+          assert r.copy("foo", "baz", db: 15)
+          assert_equal "s1", r.get("foo")
+
+          assert !r.copy("foo", "bar", db: 15)
+          assert r.copy("foo", "bar", db: 15, replace: true)
+        end
+
+        with_db(15) do
+          assert_equal "s1", r.get("baz")
+          assert_equal "s1", r.get("bar")
+        end
+      end
+    end
   end
 end