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

Mikael Arguedas ros.discourse at gmail.com
Tue Sep 26 16:17:51 UTC 2017



The quotes are present because the provided sample is using left quotes instead of "regular" single or double quotes. As a result they show up on both the ROS 1 or ROS 2 side of the bridge:
```
$ rostopic echo /joint_states 
header: 
  seq: 1
  stamp: 
    secs: 1506418567
    nsecs: 818417360
  frame_id: ''
name: ['\xe2\x80\x98shoulder_pan_joint\xe2\x80\x99', '\xe2\x80\x98shoulder_lift_joint\xe2\x80\x99', '\xe2\x80\x98elbow_joint\xe2\x80\x99', '\xe2\x80\x98wrist_1_joint\xe2\x80\x99', '\xe2\x80\x98wrist_2_joint\xe2\x80\x99', '\xe2\x80\x98wrist_3_joint\xe2\x80\x99']
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]
```

If using a sample with "regular quotes" if work fine on both sides:
```
$ 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]"
```

```
$ ros2 topic echo /joint_states sensor_msgs/JointState
header:
  stamp:
    sec: 1506418567
    nanosec: 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]

```





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