[ros-users] [Discourse.ros.org] [Next Generation ROS] Failed to read 'request_type' from a header for /rostopic

[Mikael Arguedas]

Can you specify the version of the code you are using ?
The error messages `Failed to read 'request_type'...` have been removed before the beta3 release: https://github.com/ros2/ros1_bridge/pull/91. So using beta3 or master should fix that problem.

Could you clarify what you had working before and what you are doing now?
My understanding is that:
Before you were sending joint states over `String` messages. Did you do that because it already didnt work with JointState message type ? Or did it also work with snesor_msgs/JointState at that point?

Now you have a UR10 streaming JointState messages (in ROS 1) and you try to convert them over the bridge to use them in ROS 2. Right?

If you can provide a reproducible example using only rostopic/ros2 topic of a modified talker/listener example that would allow us to help you. 

I don't have a UR10 closeby but passing joint states over the bridge seems to work with your sample:
Shell 1 : `roscore`
Shell 2: 
```
source /opt/ros/kinetic/setup.bash
rostopic pub /joint_states sensor_msgs/JointState "header:
  seq: 37197
  stamp:
    secs: 1506418567
    nsecs: 818417360
  frame_id: ''
name: [shoulder_pan_joint, shoulder_lift_joint, elbow_joint, wrist_1_joint, wrist_2_joint, wrist_3_joint]
position: [-1.5191767851458948, -1.6008179823504847, -1.594562832509176, -1.5892565886126917, 1.4281541109085083, -0.3266199270831507]
velocity: [0.0, 0.003975566942244768, -0.0, 0.0, 0.018676215782761574, 0.0]
effort: [-0.0366210974752903, 2.925110101699829, 4.784023761749268, 0.4127197563648224, 0.0269165076315403, 0.01345825381577015]"
```

Shell 3:
```
source /opt/ros/kinetic/setup.bash
source <ROS2_WS_INSTALL_DIR>/setup.bash
ros2 run ros1_bridge dynamic_bridge
```

Shell 4:
```
source <ROS2_WS_INSTALL_DIR>/setup.bash
ros2 topic echo /joint_states sensor_msgs/JointState
```

Shell 4 displays:
```
$ ros2 topic echo /joint_states sensor_msgs/JointState
header:
  stamp:
    sec: 1506418567
    nanosec: 818417360
  frame_id: ''
name: ["\u2018shoulder_pan_joint\u2019", "\u2018shoulder_lift_joint\u2019", "\u2018elbow_joint\u2019", "\u2018wrist_1_joint\u2019", "\u2018wrist_2_joint\u2019", "\u2018wrist_3_joint\u2019"]
position: [-1.5191767851458948, -1.6008179823504847, -1.594562832509176, -1.5892565886126917, 1.4281541109085083, -0.3266199270831507]
velocity: [0.0, 0.003975566942244768, -0.0, 0.0, 0.018676215782761574, 0.0]
effort: [-0.0366210974752903, 2.925110101699829, 4.784023761749268, 0.4127197563648224, 0.0269165076315403, 0.01345825381577015]
```





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