Implementation of the 'ping' command. Probably better suited for the 'active?' method.

lib/mongo/connection.rb

@@ -329,13 +329,22 @@ module Mongo
       self["admin"].command(oh)
     end
 
-        # Get the build information for the current connection.
+    # Checks if a server is alive. This command will return immediately 
+    # even if the server is in a lock.
+    #
+    # @return [Hash]
+    def ping
+      self["admin"].command({:ping => 1})
+    end
+
+    # Get the build information for the current connection.
     #
     # @return [Hash]
     def server_info
       self["admin"].command({:buildinfo => 1})
     end
 
+
     # Get the build version of the current server.
     #
     # @return [Mongo::ServerVersion]
@@ -491,7 +500,7 @@ module Mongo
     def active?
       return false unless connected?
 
-      server_info
+      ping
       true
 
       rescue ConnectionFailure

test/connection_test.rb

@@ -28,6 +28,11 @@ class TestConnection < Test::Unit::TestCase
     assert Mongo::Support.ok?(server_info)
   end
 
+  def test_ping
+    ping = @conn.ping
+    assert ping['ok']
+  end
+
   def test_connection_uri
     con = Connection.from_uri("mongodb://#{host_port}")
     assert_equal mongo_host, con.primary_pool.host