[google_chat_ros] check whether google_chat_button's parameters inclu…

[mqcmd196]

When google_chat_ros receives NoneType parameters with python dictionaries generated from json, python's .get method returns None and it cannot be serialized with string format and raises

ROSSerializationException: field action.parameters[].key must be of type bytes or an ascii string

This PR fixes it

[k-okada]

nice. can you describe how to reproduce this error ?
https://github.com/jsk-ros-pkg/jsk_3rdparty/tree/master/google_chat_ros#sending-an-interactive-button

[mqcmd196]

Using the fetch1075's credential info and launch the node like

<include file="$(find google_chat_ros)/launch/google_chat.launch">
    <arg name="use_yaml" value="false" />
    <arg name="receiving_mode" value="pubsub" />
    <arg name="project_id" value="fetch-***" />
    <arg name="subscription_id" value="chat-sub" />
    <arg name="google_cloud_credentials_json" value="/home/obinata/Downloads/fetch-***.json" />
    <arg name="respawn" value="false" />
  </include>

then run the euslisp code

(setq *chat-space* "hoge") ;; set your own google chat space name with Fetch1075
(load "package://google_chat_ros/scripts/google-chat.l")
(setq buttons (list (create-google-chat-button "hello1" "hello1") (create-google-chat-button "hello2" "hello2")))
(send-google-chat-buttons *chat-space* buttons)

You may see the button on Google Chat.

On another terminal,

rostopic echo /google_chat_ros/card_activity

then press the button on Google Chat UI and you might encounter the error.

[mqcmd196]

I wasn't sure whether to fix python code or euslisp library

(defun create-google-chat-button
    (button-name button-action-name
     &key (button-action-key) (button-action-value))
  (let ((button (instance google_chat_ros::Button :init))
        (text-button-on-click (instance google_chat_ros::OnClick :init))
        (action (instance google_chat_ros::FormAction :init))
        (parameter (instance google_chat_ros::ActionParameter :init)))
    (send button :text_button_name button-name)
    (send action :action_method_name button-action-name)
    (send parameter :key button-action-key)
    (send parameter :value button-action-value)
    (send action :parameters (list parameter))
    (send text-button-on-click :action action)
    (send button :text_button_on_click text-button-on-click)
    button))

it sets parameter 's key and value even if button-action-key and button-action-value were not given. So the button's parameter.key and parameter.value are empty.

But in any case, the element can be empty, so I modified the python node to handle it anyway.

[mqcmd196]

@k-okada Could you merge this?