why i got "rospy.ServiceException"? - python-3.x

Question

i am working with ros about 3 month! I work on a robot controller.
i got error in ui about this client:
import sys
import rospy
from database_helper.srv import get_moves, get_movesRequest, get_movesResponse, get_move
def get_data(name: str):
"""This function can extract model names from DB"""
try:
rospy.init_node("get_moves_client")
except:
pass
rospy.wait_for_service('get_moves')
try:
moves = rospy.ServiceProxy('get_moves', get_moves)
except rospy.ServiceException as e:
print(31)
print(e)
return
id = 0
try:
for i in (moves(True).moves):
if i.name == name:
id = i.id
#print(id)
break
except:
print(43)
return
rospy.wait_for_service('get_move')
move = rospy.ServiceProxy('get_move', get_move)
wps = move(id).waypoints
list_of_data = []
try:
for i in range(len(wps)):
print(i)
data = {}
data['x_traj'] = wps[i].x
data['y_traj'] = wps[i].y
data['z_traj'] = wps[i].z
data['time_tarj'] = wps[i].displacement_time_to_next_waypoint
data['order_traj'] = wps[i].order
data['pitch_traj'] = wps[i].pitch
data['roll_traj'] = wps[i].roll
data['yaw_traj'] = wps[i].yaw
data['focus_camer'] = wps[i].camera_focus
data['iris_camera'] = wps[i].camera_iris
data['rail_direction'] = wps[i].rail_direction
data['rail_speed'] = wps[i].rail_speed
data['zoom_camera'] = wps[i].camera_zoom
data['rail_time'] = wps[i].rail_time
data['rail_displacement'] = wps[i].rail_displacement
list_of_data.append(data)
except rospy.ServiceException:
pass
print(list_of_data)
return list_of_data
this client can get data from DB and save with dict and save all dict in a list.
i most write "try/except" and i see 43 number! so i know my except is in for i in range(len(wps)):
the amazing point is, i can run this script and i get answer, but if call this script in my ui, after i using save waypoint and i try to load waypoint, i get ServiceException!
my "add_move.py" code:
from typing import List, Dict
import rospy
from database_helper.srv import add_move
from database_helper.msg import move, waypoint
def _add_move(name: str, wp: List[Dict]):
"""This Function can for send insert query for DB"""
rospy.init_node('add_move_client', anonymous=True)
rospy.wait_for_service('add_move')
_move = move()
_move.name = name
for i in range(len(wp)):
_waypoint = waypoint()
_waypoint.x = wp[i]['x_traj']
_waypoint.y = wp[i]['y_traj']
_waypoint.z = wp[i]['z_traj']
_waypoint.displacement_time_to_next_waypoint = wp[i]['time_tarj']
_waypoint.pitch = wp[i]['pich_traj']
_waypoint.roll = wp[i]['roul_traj']
_waypoint.yaw = wp[i]['ya_traj']
_waypoint.camera_focus = wp[i]['focus_camer']
_waypoint.camera_iris = wp[i]['iris_camera']
_waypoint.camera_zoom = wp[i]['zoom_camera']
_waypoint.rail_speed = wp[i]['speed_rail']
_waypoint.rail_displacement = wp[i]['disp_or_time_rail']
_waypoint.rail_direction = wp[i]['direction_rail']
_move.waypoints.append(_waypoint)
add = rospy.ServiceProxy('add_move', add_move)
return add(_move).id
if __name__ == "__main__":
from random import randint
data = {'x_traj': 12, 'y_traj': 12, 'z_traj': 33, 'time_tarj': 11,
'pich_traj': 13, 'roul_traj': 43, 'ya_traj': 21,
'focus_camer': 11, 'iris_camera': 55, 'zoom_camera': 32,
'disp_or_time_rail': 21, 'speed_rail': 109, 'direction_rail':44,
'joint1_slider': 12, 'joint2_slider': 666, 'joint3_slider': 567,
'joint4_slider': 32, 'joint5_slider': 79, 'joint6_spin': 100
}
wp = []
wp.append(data)
print(_add_move("t1", wp))
my error in terminal without "try/except" is:
Traceback (most recent call last):
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/msg.py", line 223, in deserialize_messages
msg_queue.append(data.deserialize(q))
File "/home/ajax/Documents/iotive/devel/lib/python3/dist-packages/database_helper/srv/_get_moves.py", line 247, in deserialize
val2 = database_helper.msg.waypoint()
File "/home/ajax/Documents/iotive/devel/lib/python3/dist-packages/database_helper/msg/_waypoint.py", line 95, in __init__
self.rail_displacement = 0
AttributeError: 'waypoint' object attribute 'rail_displacement' is read-only
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_base.py", line 735, in receive_once
p.read_messages(b, msg_queue, sock)
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_service.py", line 361, in read_messages
rospy.msg.deserialize_messages(b, msg_queue, self.recv_data_class, queue_size=self.queue_size, max_msgs=1, start=1) #rospy.msg
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/msg.py", line 245, in deserialize_messages
raise genpy.DeserializationError("cannot deserialize: %s"%str(e))
genpy.message.DeserializationError: cannot deserialize: 'waypoint' object attribute 'rail_displacement' is read-only
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_service.py", line 522, in call
responses = transport.receive_once()
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_base.py", line 751, in receive_once
raise TransportException("receive_once[%s]: DeserializationError %s"%(self.name, str(e)))
rospy.exceptions.TransportException: receive_once[/get_moves]: DeserializationError cannot deserialize: 'waypoint' object attribute 'rail_displacement' is read-only
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "./benchmark_new_version_4_1.py", line 730, in get_data_query
self.wp_saver = get_data(response)
File "/home/ajax/Documents/iotive/src/gui/ui/scripts/get_moves_clinet.py", line 36, in get_data
for i in (moves(True).moves):
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_service.py", line 442, in __call__
return self.call(*args, **kwds)
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/impl/tcpros_service.py", line 532, in call
raise ServiceException("transport error completing service call: %s"%(str(e)))
rospy.service.ServiceException: transport error completing service call: receive_once[/get_moves]: DeserializationError cannot deserialize: 'waypoint' object attribute 'rail_displacement' is read-only
what is my wrong?
srv/get_move:
int32 id
---
waypoint[] waypoints
srv/get_moves:
bool add_waypoints
---
move[] moves
msg/move:
int32 id
string name
waypoint[] waypoints
msg/waypoint:
int32 id
int32 order
float64 x
float64 y
float64 z
float64 roll
float64 pitch
float64 yaw
int32 camera_focus
int32 camera_iris
int32 camera_zoom
int32 rail_displacement
int32 rail_time
int32 rail_speed
bool rail_direction
int32 displacement_time_to_next_waypoint

Answer 1

So we need to remove service variables when we do not have anything else.
like this:
rospy.wait_for_service('get_moves')
moves = rospy.ServiceProxy('get_moves', get_moves)
id = 0
for i in (moves(True).moves):
if i.name == name:
id = i.id
#print(id)
break
rospy.wait_for_service('get_move')
move = rospy.ServiceProxy('get_move', get_move)
wps = move(id).waypoints
list_of_data = []
for i in range(len(wps)):
print(i)
data = {}
data['order_traj'] = wps[i].order
data['x_traj'] = wps[i].x
data['y_traj'] = wps[i].y
data['z_traj'] = wps[i].z
data['time_tarj'] = wps[i].displacement_time_to_next_waypoint
data['order_traj'] = wps[i].order
data['pitch_traj'] = wps[i].pitch
data['roll_traj'] = wps[i].roll
data['yaw_traj'] = wps[i].yaw
data['focus_camer'] = wps[i].camera_focus
data['iris_camera'] = wps[i].camera_iris
data['rail_direction'] = wps[i].rail_direction
data['rail_speed'] = wps[i].rail_speed
data['zoom_camera'] = wps[i].camera_zoom
data['rail_time'] = wps[i].rail_time
data['rail_displacement'] = wps[i].rail_displacement
list_of_data.append(data)
del move
del moves
print(list_of_data)
return list_of_data
I discovered this last night!