Added an http proxy for gps

Fixed example syntax in comments

Added GPLv3 acknowledgement

Removed fstrings for 3.5 requirements

Removed f-string mistake for 3.5

examples/gps_web.py

@@ -0,0 +1,242 @@
+#!/usr/bin/python3
+
+"""
+A webserver for GPS updates.
+
+This code may be useful in situations where a companion computer is connected
+to the ArduPilot board and is able to run mavproxy with an output on the IP and
+port as defined in the runtime arguments.  The expected use is that the output
+of an external GPS is transmitted over http to the companion as a proxy for the
+ArduPilot connection.
+
+A typical set of ArduPilot parameters for using this code:
+    EK3_SRC1_POSXY == 3  (GPS)
+    EK3_SRC1_POSZ  == 3  (GPS)
+    EK3_SRC1_VELXY == 3  (GPS)
+    EK3_SRC1_VELZ  == 3  (GPS)
+    EK3_SRC1_YAW   == 3  (GPS with compass fallback)
+    GPS_TYPE       == 14 (MAV)
+
+Example syntax for running this code:
+    python3 ./gps_web.py -m 127.0.0.1 -s 127.0.0.1 -d
+
+Example SITL syntax:
+    python3 ./sim_vehicle.py -v ArduCopter --console --map --out 127.0.0.1:9898
+
+An example of the expected type of input to the webserver:
+    'GPS_ms':'236755470'                                                        ## integer
+    'GPS_week':'2272'                                                           ## integer
+    'Fix':'5'                                                                   ## integer
+    'Lat':'45.60451248'                                                         ## float
+    'Lon':'-122.63580536'                                                       ## float
+    'Alt':'0.0000'                                                              ## float
+    'HDOP':'0.10'                                                               ## float
+    'VDOP':'0.10'                                                               ## float
+    'SpeedNorth':'0.25'                                                         ## float
+    'SpeedEast':'-1.91'                                                         ## float
+    'Heading':'92.806'                                                          ## float
+
+Message testing with curl:
+    ** Linux
+    curl -X POST http://127.0.0.1:10000 -H 'Content-Type: application/json' -i -d '{"GPS_ms":"236755470","GPS_week":"2272","Fix":"5","Lat":"-35.36609329","Lon":"149.17195595","Alt":"0.0000","HDOP":"0.10","VDOP":"0.10","SpeedNorth":"0.25","SpeedEast":"-1.91","Heading":"92.806"}'
+
+    ** Windows
+    curl -X POST http://127.0.0.1:10000 -H 'Content-Type: application/json' -i -d {'GPS_ms':'236755470','GPS_week':'2272','Fix':'5','Lat':'45.60451248','Lon':'-122.63580536','Alt':'0.0000','HDOP':'0.10','VDOP':'0.10','SpeedNorth':'0.25','SpeedEast':'-1.91','Heading':'92.806'}
+
+Released under the GNU GPL version 3 by stryngs
+"""
+
+import argparse
+import ast
+import psutil
+import threading
+import time
+from http.server import ThreadingHTTPServer, BaseHTTPRequestHandler
+from io import BytesIO
+from pymavlink import mavutil, mavwp
+from queue import Queue
+
+class Heartbeat():
+    """Setup and hold the heartbeat"""
+    __slots__ = ('heartBeat')
+    def __init__(self, parent):
+        self.heartBeat = threading.Thread(target = parent.heartBeat)
+        self.heartBeat.daemon = True
+        self.heartBeat.start()
+
+
+class Webapp():
+    """Provide an input"""
+    __slots__ = ('webApp')
+    def __init__(self, parent):
+        self.webApp = threading.Thread(target = parent.webApp)
+        self.webApp.daemon = True
+        self.webApp.start()
+
+
+class Gpsloop():
+    """Launch GPS"""
+    __slots__ = ('gpsLoop')
+    def __init__(self, parent):
+        self.gpsLoop = threading.Thread(target = parent.gpsLoop)
+        self.gpsLoop.daemon = True
+        self.gpsLoop.start()
+        print('[~] Waiting for GPS')
+
+
+class httpHandler(BaseHTTPRequestHandler):
+    """A threaded handler for web requests"""
+
+    def do_POST(self):
+        content_length = int(self.headers['Content-Length'])
+        body = self.rfile.read(content_length)
+        global gList_
+
+        try:
+            coord = ast.literal_eval(body.decode())
+
+            ## gps
+            try:
+                lt = coord.get('Lat').split('.')
+                theLat = int(lt[0] + lt[1][:7].ljust(7, '0'))
+                ln = coord.get('Lon').split('.')
+                theLon = int(ln[0] + ln[1][:7].ljust(7, '0'))
+                hd = coord.get('Heading').split('.')
+                theHdg = int(hd[0] + hd[1][:2].ljust(2, '0'))
+
+                ## Update the gps list
+                gList_.append((int(psutil.boot_time()),                         # Timestamp (micros since boot or Unix epoch)
+                               0,                                               # ID of the GPS for multiple GPS inputs
+                               0,                                               # (mavutil.mavlink.GPS_INPUT_IGNORE_FLAG_VEL_HORIZ | mavutil.mavlink.GPS_INPUT_IGNORE_FLAG_VEL_VERT | mavutil.mavlink.GPS_INPUT_IGNORE_FLAG_SPEED_ACCURACY),
+                               int(coord.get('GPS_ms')),                        # GPS time (milliseconds from start of GPS week)
+                               int(coord.get('GPS_week')),                      # GPS week number
+                               int(coord.get('Fix')),                           # 0-1: no fix, 2: 2D fix, 3: 3D fix. 4: 3D with DGPS. 5: 3D with RTK
+                               theLat,                                          # Latitude (WGS84), in degrees * 1E7
+                               theLon,                                          # Longitude (WGS84), in degrees * 1E7
+                               float(coord.get('Alt')),                         # Altitude (AMSL, not WGS84), in m (positive for up)
+                               float(coord.get('HDOP')),                        # GPS HDOP horizontal dilution of position in m
+                               float(coord.get('VDOP')),                        # GPS VDOP vertical dilution of position in m
+                               float(coord.get('SpeedNorth')),                  # GPS velocity in m/s in NORTH direction in earth-fixed NED frame
+                               float(coord.get('SpeedEast')),                   # GPS velocity in m/s in EAST direction in earth-fixed NED frame
+                               0,                                               # GPS velocity in m/s in DOWN direction in earth-fixed NED frame
+                               .1,                                              # GPS speed accuracy in m/s
+                               .1,                                              # GPS horizontal accuracy in m
+                               .1,                                              # GPS vertical accuracy in m
+                               10,                                              # Number of satellites visible.
+                               theHdg))                                         # Yaw of vehicle relative to Earth's North, zero means not available, use 36000 for north
+                self.send_response(200)
+                self.end_headers()
+                response = BytesIO()
+                response.write(body)
+                response.write(b'\n')
+                self.wfile.write(response.getvalue())
+            except Exception as E:
+                print('Responding with a 500 - inner try')
+                self.send_response(500)
+                self.end_headers()
+                response = BytesIO()
+                self.wfile.write(response.getvalue())
+                print(E)
+        except Exception as E:
+            print('Responding with a 500 - outer try')
+            self.send_response(500)
+            self.end_headers()
+            response = BytesIO()
+            self.wfile.write(response.getvalue())
+            print(E)
+
+
+class Parent(object):
+    """Parent class responsible for user interactions and backgrounding"""
+
+    def __init__(self, args):
+        self.args = args
+        self.gList = []
+        if self.args.mport is None:
+            mport = 9898
+        else:
+            mport = self.args.mport
+        print('[~] Waiting on MAVLink')
+        self.m = mavutil.mavlink_connection('udpin:%s:%s' % (self.args.m, mport))
+        self.m.wait_heartbeat(blocking = True)
+        print('[~] MAVLink established')
+
+    def gpsLoop(self):
+        """
+        Loops on self.gList and looks for a new object.  pop(0) approach.
+        If no object, sleep @ .001
+        """
+        print('[~] Creating GPS input loop')
+        while True:
+            try:
+                if len(self.gList) > 0:
+
+                    ## Values from POST
+                    gpsT = self.gList.pop(0)
+                    self.m.mav.gps_input_send(gpsT[0],
+                                              gpsT[1],
+                                              gpsT[2],
+                                              gpsT[3],
+                                              gpsT[4],
+                                              gpsT[5],
+                                              gpsT[6],
+                                              gpsT[7],
+                                              gpsT[8],
+                                              gpsT[9],
+                                              gpsT[10],
+                                              gpsT[11],
+                                              gpsT[12],
+                                              gpsT[13],
+                                              gpsT[14],
+                                              gpsT[15],
+                                              gpsT[16],
+                                              gpsT[17],
+                                              gpsT[18])
+            except Exception as E:
+                print(E)
+            time.sleep(.001)
+
+    def heartBeat(self):
+        """Drains the queue for accuracy"""
+        while True:
+            self.m.recv_msg()
+            time.sleep(.001)
+
+    def webApp(self):
+        """Run a webapp to handle simple post requests"""
+        print('[~] Launching webapp')
+        if self.args.wport is None:
+            wport = 10000
+        else:
+            wport = int(self.args.wport)
+        self.server = ThreadingHTTPServer((self.args.s, wport), httpHandler)
+        self.server.serve_forever()
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-d', action = 'store_true', help = 'Do not background')
+    parser.add_argument('-m', help = 'Mavlink IP', required = True)
+    parser.add_argument('-s', help = 'Webserver IP', required = True)
+    parser.add_argument('--mport', help = 'Mavlink port [Default is 9898]')
+    parser.add_argument('--wport', help = 'Webserver port [Default is 10000]')
+
+    args = parser.parse_args()
+
+    ## Grab parent obj
+    f = Parent(args)
+    gList_ = f.gList
+    Heartbeat(f)
+    Webapp(f)
+    Gpsloop(f)
+
+    ## Acquire current GPS location and set as home
+    homeLoc = f.m.location()
+    f.homeLat = homeLoc.lat
+    f.homeLon = homeLoc.lng
+    print('[~] GPS acquired')
+
+    ## Server mode
+    if args.d is True:
+        print('[~] Server mode launched')
+        while True:
+            time.sleep(1000)