Python 3: define basestring, use bytes.decode() (#705)

* Run flake8 tests against both Python 2 and 3

* Python 3: from past.builtins import basestring

* Python 3: from __future__ import print_function

* Update simple_goto.py

* flake8 --max-line-length=127

* Python 3: from __future__ import print_function

* Separate flak8 run just for syntax errors

Author: cclauss

.travis.yml

@@ -1,3 +1,5 @@
+language: python
+
 env:
   global:
     - SITL_SPEEDUP=10
@@ -7,18 +9,26 @@ python:
   - 2.7.13
   - 3.6
 
+before_install:
+  - pip install --upgrade pip
+  
 install:
-  - 'pip install -r requirements.txt'
+  - pip install -r requirements.txt
+  - pip install flake8
+
+before_script:
+  # --exit-zero means that flake8 will not stop the build
+  # 127 characters is the width of a GitHub editor
+  - flake8 . --count --exit-zero  --max-line-length=127 --select=E999 --statistics  # syntax errors
+  - flake8 . --count --exit-zero  --max-line-length=127 --statistics
 
 script:
-  - 'nosetests --debug=nose,nose.importer --debug-log=nose_debug -svx dronekit.test.unit'
-  - 'nosetests --debug=nose,nose.importer --debug-log=nose_debug -svx dronekit.test.sitl'
+  - nosetests --debug=nose,nose.importer --debug-log=nose_debug -svx dronekit.test.unit
+  - nosetests --debug=nose,nose.importer --debug-log=nose_debug -svx dronekit.test.sitl
 
 git:
   depth: 10
 
-language: python
-
 notifications:
   email: false
   webhooks:

dronekit/__init__.py

@@ -31,23 +31,26 @@
 """
 
 from __future__ import print_function
-import monotonic
-import time
-import socket
-import sys
+import collections
+import copy
+import math
 import os
+import struct
 import platform
-import re
-from dronekit.util import errprinter
-from pymavlink import mavutil, mavwp
 from queue import Queue, Empty
+import re
+import socket
+import sys
+import threading
 from threading import Thread
+import time
 import types
-import threading
-import math
-import struct
-import copy
-import collections
+
+import monotonic
+from past.builtins import basestring
+from dronekit.util import errprinter
+
+from pymavlink import mavutil, mavwp
 from pymavlink.dialects.v10 import ardupilotmega
 
 
@@ -88,7 +91,8 @@ def __init__(self, pitch, yaw, roll):
         self.roll = roll
 
     def __str__(self):
-        return "Attitude:pitch=%s,yaw=%s,roll=%s" % (self.pitch, self.yaw, self.roll)
+        fmt = '{}:pitch={pitch},yaw={yaw},roll={roll}'
+        return fmt.format(self.__class__.__name__, **vars(self))
 
 
 class LocationGlobal(object):
@@ -2747,7 +2751,7 @@ def __len__(self):
 
     def __getitem__(self, index):
         if isinstance(index, slice):
-            return [self[ii] for ii in xrange(*index.indices(len(self)))]
+            return [self[ii] for ii in range(*index.indices(len(self)))]
         elif isinstance(index, int):
             item = self._vehicle._wploader.wp(index + 1)
             if not item:
@@ -2835,7 +2839,7 @@ def connect(ip,
 
         @vehicle.on_message('STATUSTEXT')
         def listener(self, name, m):
-            status_printer(re.sub(r'(^|\n)', '>>> ', m.text.rstrip()))
+            status_printer(re.sub(r'(^|\n)', '>>> ', m.text.decode('utf-8').rstrip()))
 
     if _initialize:
         vehicle.initialize(rate=rate, heartbeat_timeout=heartbeat_timeout)

examples/drone_delivery/drone_delivery.py

@@ -3,39 +3,39 @@
 
 """
 © Copyright 2015-2016, 3D Robotics.
-drone_delivery.py: 
+drone_delivery.py:
 
 A CherryPy based web application that displays a mapbox map to let you view the current vehicle position and send the vehicle commands to fly to a particular latitude and longitude.
 
 Full documentation is provided at http://python.dronekit.io/examples/drone_delivery.html
 """
 
+from __future__ import print_function
 import os
 import simplejson
 import time
-from pymavlink import mavutil
+
 from dronekit import connect, VehicleMode, LocationGlobal, LocationGlobalRelative
 import cherrypy
-from cherrypy.process import wspbus, plugins
 from jinja2 import Environment, FileSystemLoader
 
-#Set up option parsing to get connection string
-import argparse  
+# Set up option parsing to get connection string
+import argparse
 parser = argparse.ArgumentParser(description='Creates a CherryPy based web application that displays a mapbox map to let you view the current vehicle position and send the vehicle commands to fly to a particular latitude and longitude. Will start and connect to SITL if no connection string specified.')
-parser.add_argument('--connect', 
-                   help="vehicle connection target string. If not specified, SITL is automatically started and used.")
+parser.add_argument('--connect',
+                    help="vehicle connection target string. If not specified, SITL is automatically started and used.")
 args = parser.parse_args()
 
-connection_string=args.connect
+connection_string = args.connect
 
-#Start SITL if no connection string specified
+# Start SITL if no connection string specified
 if not connection_string:
     import dronekit_sitl
     sitl = dronekit_sitl.start_default()
     connection_string = sitl.connection_string()
 
-local_path=os.path.dirname(os.path.abspath(__file__))
-print "local path: %s" % local_path
+local_path = os.path.dirname(os.path.abspath(__file__))
+print("local path: %s" % local_path)
 
 
 cherrypy_conf = {
@@ -89,11 +89,10 @@ def takeoff(self):
         self._log("Taking off")
         self.vehicle.simple_takeoff(30.0)
 
-        
     def arm(self, value=True):
         if value:
             self._log('Waiting for arming...')
-            self.vehicle.armed = True    
+            self.vehicle.armed = True
             while not self.vehicle.armed:
                 time.sleep(.1)
         else:
@@ -104,11 +103,9 @@ def _run_server(self):
         # Start web server if enabled
         cherrypy.tree.mount(DroneDelivery(self), '/', config=cherrypy_conf)
 
-        cherrypy.config.update({
-            'server.socket_port': 8080,
-            'server.socket_host': '0.0.0.0',
-            'log.screen': None
-         })
+        cherrypy.config.update({'server.socket_port': 8080,
+                                'server.socket_host': '0.0.0.0',
+                                'log.screen': None})
 
         print('''Server is bound on all addresses, port 8080
 You may connect to it using your web broser using a URL looking like this:
@@ -153,28 +150,26 @@ def location_callback(self, vehicle, name, location):
         self.current_location = location.global_relative_frame
 
     def _log(self, message):
-        print "[DEBUG]: {0}".format(message)
+        print("[DEBUG]: {0}".format(message))
+
 
 class Templates:
     def __init__(self, home_coords):
         self.home_coords = home_coords
         self.options = self.get_options()
-        self.environment = Environment(loader=FileSystemLoader( local_path + '/html'))
+        self.environment = Environment(loader=FileSystemLoader(local_path + '/html'))
 
     def get_options(self):
-        return {
-                'width': 670,
+        return {'width': 670,
                 'height': 470,
                 'zoom': 13,
                 'format': 'png',
                 'access_token': 'pk.eyJ1Ijoia2V2aW4zZHIiLCJhIjoiY2lrOGoxN2s2MDJzYnR6a3drbTYwdGxmMiJ9.bv5u7QgmcJd6dZfLDGoykw',
                 'mapid': 'kevin3dr.n56ffjoo',
                 'home_coords': self.home_coords,
-                'menu': [
-                    {'name': 'Home', 'location': '/'},
-                    {'name': 'Track', 'location': '/track'},
-                    {'name': 'Command', 'location': '/command'}
-                    ],
+                'menu': [{'name': 'Home', 'location': '/'},
+                         {'name': 'Track', 'location': '/track'},
+                         {'name': 'Command', 'location': '/command'}],
                 'current_url': '/',
                 'json': ''
                 }
@@ -198,9 +193,10 @@ def command(self, current_coords):
         return self.get_template('command')
 
     def get_template(self, file_name):
-        template = self.environment.get_template( file_name + '.html')
+        template = self.environment.get_template(file_name + '.html')
         return template.render(options=self.options)
 
+
 class DroneDelivery(object):
     def __init__(self, drone):
         self.drone = drone
@@ -230,13 +226,13 @@ def track(self, lat=None, lon=None):
 
 
 # Connect to the Vehicle
-print 'Connecting to vehicle on: %s' % connection_string
+print('Connecting to vehicle on: %s' % connection_string)
 vehicle = connect(connection_string, wait_ready=True)
 
-print 'Launching Drone...'
+print('Launching Drone...')
 Drone().launch()
 
-print 'Waiting for cherrypy engine...'
+print('Waiting for cherrypy engine...')
 cherrypy.engine.block()
 
 if not args.connect:

examples/simple_goto/simple_goto.py

@@ -10,30 +10,31 @@
 Full documentation is provided at http://python.dronekit.io/examples/simple_goto.html
 """
 
-from dronekit import connect, VehicleMode, LocationGlobalRelative
+from __future__ import print_function
 import time
+from dronekit import connect, VehicleMode, LocationGlobalRelative
 
 
-#Set up option parsing to get connection string
-import argparse  
+# Set up option parsing to get connection string
+import argparse
 parser = argparse.ArgumentParser(description='Commands vehicle using vehicle.simple_goto.')
-parser.add_argument('--connect', 
-                   help="Vehicle connection target string. If not specified, SITL automatically started and used.")
+parser.add_argument('--connect',
+                    help="Vehicle connection target string. If not specified, SITL automatically started and used.")
 args = parser.parse_args()
 
 connection_string = args.connect
 sitl = None
 
 
-#Start SITL if no connection string specified
+# Start SITL if no connection string specified
 if not connection_string:
     import dronekit_sitl
     sitl = dronekit_sitl.start_default()
     connection_string = sitl.connection_string()
 
 
 # Connect to the Vehicle
-print 'Connecting to vehicle on: %s' % connection_string
+print('Connecting to vehicle on: %s' % connection_string)
 vehicle = connect(connection_string, wait_ready=True)
 
 
@@ -42,62 +43,63 @@ def arm_and_takeoff(aTargetAltitude):
     Arms vehicle and fly to aTargetAltitude.
     """
 
-    print "Basic pre-arm checks"
+    print("Basic pre-arm checks")
     # Don't try to arm until autopilot is ready
     while not vehicle.is_armable:
-        print " Waiting for vehicle to initialise..."
+        print(" Waiting for vehicle to initialise...")
         time.sleep(1)
 
-        
-    print "Arming motors"
+    print("Arming motors")
     # Copter should arm in GUIDED mode
     vehicle.mode = VehicleMode("GUIDED")
-    vehicle.armed = True    
+    vehicle.armed = True
 
     # Confirm vehicle armed before attempting to take off
-    while not vehicle.armed:      
-        print " Waiting for arming..."
+    while not vehicle.armed:
+        print(" Waiting for arming...")
         time.sleep(1)
 
-    print "Taking off!"
-    vehicle.simple_takeoff(aTargetAltitude) # Take off to target altitude
+    print("Taking off!")
+    vehicle.simple_takeoff(aTargetAltitude)  # Take off to target altitude
 
-    # Wait until the vehicle reaches a safe height before processing the goto (otherwise the command 
-    #  after Vehicle.simple_takeoff will execute immediately).
+    # Wait until the vehicle reaches a safe height before processing the goto
+    #  (otherwise the command after Vehicle.simple_takeoff will execute
+    #   immediately).
     while True:
-        print " Altitude: ", vehicle.location.global_relative_frame.alt 
-        #Break and return from function just below target altitude.        
-        if vehicle.location.global_relative_frame.alt>=aTargetAltitude*0.95: 
-            print "Reached target altitude"
+        print(" Altitude: ", vehicle.location.global_relative_frame.alt)
+        # Break and return from function just below target altitude.
+        if vehicle.location.global_relative_frame.alt >= aTargetAltitude * 0.95:
+            print("Reached target altitude")
             break
         time.sleep(1)
 
+
 arm_and_takeoff(10)
 
-print "Set default/target airspeed to 3"
+print("Set default/target airspeed to 3")
 vehicle.airspeed = 3
 
-print "Going towards first point for 30 seconds ..."
+print("Going towards first point for 30 seconds ...")
 point1 = LocationGlobalRelative(-35.361354, 149.165218, 20)
 vehicle.simple_goto(point1)
 
 # sleep so we can see the change in map
 time.sleep(30)
 
-print "Going towards second point for 30 seconds (groundspeed set to 10 m/s) ..."
+print("Going towards second point for 30 seconds (groundspeed set to 10 m/s) ...")
 point2 = LocationGlobalRelative(-35.363244, 149.168801, 20)
 vehicle.simple_goto(point2, groundspeed=10)
 
 # sleep so we can see the change in map
 time.sleep(30)
 
-print "Returning to Launch"
+print("Returning to Launch")
 vehicle.mode = VehicleMode("RTL")
 
-#Close vehicle object before exiting script
-print "Close vehicle object"
+# Close vehicle object before exiting script
+print("Close vehicle object")
 vehicle.close()
 
 # Shut down simulator if it was started.
-if sitl is not None:
+if sitl:
     sitl.stop()