Added convenience methods to create empty action goals with BabelFish.

(cherry picked from commit dcf7930)

ros_babel_fish/include/ros_babel_fish/babel_fish.hpp

@@ -143,7 +143,7 @@ class BabelFish : public std::enable_shared_from_this<BabelFish>
 
   /*!
    * Creates an empty message of the given type.
-   * @param type The message type, e.g.: "std_msgs/Header"
+   * @param type The message type, e.g.: "std_msgs/msg/Header"
    * @return An empty message of the given type
    *
    * @throws BabelFishException If the message description was not found
@@ -155,7 +155,7 @@ class BabelFish : public std::enable_shared_from_this<BabelFish>
 
   /*!
    * Creates a service request message for the given service type.
-   * @param type The type of the service, e.g., rosapi/GetParam
+   * @param type The type of the service, e.g., rcl_interfaces/srv/GetParameters
    * @return An empty service request message that can be used to call a service of the given type
    *
    * @throws BabelFishException If the service description was not found
@@ -165,6 +165,16 @@ class BabelFish : public std::enable_shared_from_this<BabelFish>
   //! @copydoc create_service_request
   CompoundMessage::SharedPtr create_service_request_shared( const std::string &type ) const;
 
+  /*!
+   * Creates an empty action goal for the given action type.
+   * @param type The type of the action, e.g., example_interfaces/action/Fibonacci
+   * @return An empty action goal message that can be used to send a goal to an action server.
+   */
+  CompoundMessage create_action_goal( const std::string &type ) const;
+
+  //! @copydoc create_action_goal_request
+  CompoundMessage::SharedPtr create_action_goal_shared( const std::string &type ) const;
+
   MessageTypeSupport::ConstSharedPtr get_message_type_support( const std::string &type ) const;
 
   ServiceTypeSupport::ConstSharedPtr get_service_type_support( const std::string &type ) const;

ros_babel_fish/src/babel_fish.cpp

@@ -235,6 +235,25 @@ CompoundMessage::SharedPtr BabelFish::create_service_request_shared( const std::
   return CompoundMessage::make_shared( type_support->request() );
 }
 
+CompoundMessage BabelFish::create_action_goal( const std::string &type ) const
+{
+  const ActionTypeSupport::ConstSharedPtr &type_support = get_action_type_support( type );
+  if ( type_support == nullptr ) {
+    throw BabelFishException( "BabelFish doesn't know an action of type: " + type );
+  }
+  MessageMembersIntrospection introspection = type_support->goal_service_type_support->request();
+  size_t index =
+      std::find_if( introspection->members_, introspection->members_ + introspection->member_count_,
+                    []( const auto &a ) { return std::strcmp( a.name_, "goal" ) == 0; } ) -
+      introspection->members_;
+  return CompoundMessage( type_support->goal_service_type_support->request().getMember( index ) );
+}
+
+CompoundMessage::SharedPtr BabelFish::create_action_goal_shared( const std::string &type ) const
+{
+  return CompoundMessage::make_shared( create_action_goal( type ) );
+}
+
 MessageTypeSupport::ConstSharedPtr BabelFish::get_message_type_support( const std::string &type ) const
 {
   for ( const auto &provider : type_support_providers_ ) {