The gazebo_state_plugins package - JenniferBuehler/gazebo-pkgs GitHub Wiki
The package gazebo_state_plugins contains a collection of Gazebo "World" plugins which can be used to share information about the World in Gazebo with other ROS nodes.
The package gazebo_world_plugin_loader can be used to to load the world plugins, alternatively to specifying the plugins to be loaded in the Gazebo world file.
The package gazebo_state_plugins offers the "Gazebo object information service". Please refer to the wiki about the object information pipeline for more details about this plugin and how it works together with the "fake object recognizer" which you can find in package gazebo_test_toosl.