Cannot get the message using rosbag2 and rclpy

Question

Good day everyone,

I've been struggling with this for two days now. and I can't seem to find a solution. I have a dictionary with topic names and their types, what is the correct module to read the message using rcl?

while reader.has_next():
    topic, message, timestamp = reader.read_next()
    if topic in topic_names:
        message_type_str = topics_dict.get(topic)
        msg = _rclpy.rclpy_deserialize(message, message_type_str)
        print(msg)
        # msg_type = get_message(msg_type_str)
        # msg = deserialize_message(message, msg_type)
        # print(msg)
        # print(topic)
        # print(message_type)
        # print("===================================")

Answer 1

I found the solution, for anyone that is interested the correct method is as below:

topic_types = reader.get_all_topics_and_types()
type_map = {topic_types[i].name: topic_types[i].type for i in range(len(topic_types))}

storage_filter = rosbag2_py.StorageFilter(topics=topic_names)
reader.set_filter (storage_filter)

while reader.has_next():
    topic, message, timestamp = reader.read_next()
    message_type = get_message(type_map[topic])
    msg = deserialize_message (message, message_type)
    print (msg)