rclnodejs generate-ros-messages ROS2-Shared memory

[Tombliboo96]

Description
Hi, I am using npx generate-ros-messages to parse the idl files in
https://github.com/ZhenshengLee/ros2_shm_msgs
and run a nodejs project. However, when running the project, there is an error in the generated js file under node_modules/rclnodejs/generated/ due to incorrect field names parsed by
deallocator.freeStructMember(refObject, UInt8Wrapper.refObjectType, 'size');
I found that only the data field is returned in Uint8Wrapper while idl files also contain both data and size fields.

• Library Version: nodejs 18.19.1/20.11.1
• ROS Version: ROS2 humble /rclnodejs 0.26.0
• Platform / OS:

Steps To Reproduce

I use https://github.com/ZhenshengLee/ros2_shm_msgs project to send ImageData to connect with rclnodejs, deploy the msg in the project to the system, and use the generate-ros-messages in rclnodejs for js conversion. Nodejs receives data through rosSubscriber

Expected Behavior
I want to connect to rclnodejs using shared memory in ROS2, not sure if it is feasible

Actual Behavior

[minggangw]

Hi @Tombliboo96 thanks for your feedback, rclnodejs leverages v8::ArrayBuffer to eliminate additional memory copy when receiving messages from rcl, and it only works for the array of type:

['int8', 'uint8', 'int16', 'uint16', 'int32', 'uint32', 'float64', 'float32', 'char', 'byte']

Not sure it's what you called "shared memory", so do you meet any errors, like crashing?

[Tombliboo96]

Hi, @minggangw I got an error when using generate-ros-messages to convert idl file to js file and apply,
The content of the IDL file is as follows:
module shm_msgs {
module msg {
typedef uint8 uint8__256[256];
module String_Constants {
const uint8 MAX_SIZE = 255;
};
struct String {
uint8__256 data;

  @default (value=0)
  uint8 size;
};

};
};
Viewing the generated js file found that the problem in the last uint8 size field cannot be passed through the system's built-in std_Uint8

[minggangw]

Currently, rclnodejs doesn't support .idl files, are you sure the JS files are generated accordingly? Also, please check with #764

[Tombliboo96]

I use the generate-ros-messages tool described in https://github.com/RobotWebTools/rclnodejs to generate the corresponding js file for the IDL file, and found the generated js file in /node_modules/rclnodejs/generated/, but it cannot be used normally;
The content of the IDL file is as follows:
`module shm_msgs {
module msg {
typedef uint8 uint8__256[256];
module String_Constants {
const uint8 MAX_SIZE = 255;
};
struct String {
uint8__256 data;

@default (value=0)
uint8 size;
};
};
};`
The error pointed out occurs when recognizing the size in the above field.

[minggangw]

Would you share your .msg file if you have?

[Tombliboo96]

char[256] data
uint8 size 0
uint8 MAX_SIZE=255

[Tombliboo96]

@minggangw Thank you for your reply, it's my problem, thank you

[minggangw]

So I will close this issue, thanks!