api.py 文件源码

def post_topic_message(topic_name):
    """
    POST /api/<version>/topic/<topic_name>

    POST a message to a ROS topic by name.

    Requires a JSON payload of shape: ``[x, y, z]``. The values of the JSON
    array must match the argument types of the topic's type constructor.
    """
    topic_name = "/" + topic_name
    # Get the list of ROS topics in the system.
    # Returns a list of [topic, type_string] pairs.
    topic_list = rostopic_master.getTopicTypes()
    # Find topic in list (this is Python's approach to find).
    try:
        topic_match = next(x for x in topic_list if x[0] == topic_name)
    except StopIteration:
        # If we can't find the topic, return early (400 bad request).
        return error("Topic does not exist")
    json = request.get_json(silent=True)
    args = json if json else []
    try:
        # Get the message type constructor for the topic's type string.
        MsgType = get_message_class(topic_match[1])
        pub = rospy.Publisher(topic_name, MsgType, queue_size=10)
        # Unpack JSON list and pass to publish.
        # pub.publish() will pass the list of arguments to the message
        # type constructor.
        pub.publish(*args)
    except Exception, e:
        return error("Wrong arguments for topic type constructor")
    return success("Posted message to topic")