Implemented the (not yet fully working) communication class. Added error handling to move.py and fixed the node list in planettest.py.

src/communication.py

@@ -1,27 +1,153 @@
 #!/usr/bin/env python3
-# Suggestion: Do not import the ev3dev.ev3 module in this file
+
+from planet import Planet, Direction
+from enum import Enum
+
+"""
+Class to hold the MQTT client
+
+Documentation:
+On start do the following (make part of __init__):
+(1) subscribe to explorer/<N>
+(2) publish to explorer/<N>: SYN ready
+
+Next receive the planet name and starting coordinates
+(1) receive from explorer/<N>: ACK <Name> <X>,<Y>
+(2) subscribe to planet/<Name>
+
+on_message:
+Called when a message has been received on a topic that the client subscribes to and the message does not match an existing topic filter callback. Use message_callback_add() to define a callback that will be called for specific topic filters. on_message will serve as fallback when none matched.
+client
+    the client instance for this callback
+userdata
+    the private user data as set in Client() or user_data_set()
+message
+    an instance of MQTTMessage. This is a class with members topic, payload, qos, retain.
+
+
+mqtt message Documentation:
+ |  Members:
+ |
+ |  topic : String. topic that the message was published on.
+ |  payload : String/bytes the message payload.
+ |  qos : Integer. The message Quality of Service 0, 1 or 2.
+ |  retain : Boolean. If true, the message is a retained message and not fresh.
+ |  mid : Integer. The message id.
+"""
+
+
+def str2dir(string):
+    return {
+        'N': Direction.NORTH,
+        'E': Direction.EAST,
+        'S': Direction.SOUTH,
+        'W': Direction.WEST
+    }.get(string)
+
+
+def dir2str(direction):
+    return {
+        Direction.NORTH: 'N',
+        Direction.EAST: 'E',
+        Direction.SOUTH: 'S',
+        Direction.WEST: 'W'
+    }.get(direction)
+
+
+def str2tuple(string_a, string_b):
+    return (eval(string_a), eval(string_b))
+
+
+def tupel2str(int_a, int_b):
+    return str(int_a) + ',' + str(int_b)
+
+
+class Command(str, Enum):
+    SEND = "SYN "     # SYN is short for synchronize
+    RECEIVE = "ACK "  # ACK is short for acknowledge
+    READY = "ready"
+    PATH = "path "
+    TARGET = "target "
+    COMPLETE = "exploration completed!"
+    NOTICE = "notice"
+
 
 class Communication:
-    """
+    """ Initializes communication module, connect to server, subscribe, etc. """
-        Class to hold the MQTT client
+    def __init__(self, mqtt_client):
-
-        Feel free to add functions, change the constructor and the example send_message() to satisfy your requirements and thereby solve the task according to the specifications
-    """
-
-    def __init__(self, mqtt_client, planet):
-        """ Initializes communication module, connect to server, subscribe, etc. """
         # THESE TWO VARIABLES MUST NOT BE CHANGED
+        self.msg_queue = []
+        self.planetname = None
+        self.planet = Planet()
         self.client = mqtt_client
         self.client.on_message = self.on_message
-
+        self.uid = '122'
-        # ADD YOUR VARIABLES HERE
+        passwd = '7KMuWPT2UE'
+        self.client.username_pw_set(self.uid, password=passwd)
+        try:
+            self.client.connect('robolab.inf.tu-dresden.de', port=8883)
+        except OSError:
+            print("ERROR: check your network connection.")
+        self.subscribetochannel("explorer/" + self.uid)
+        self.encode_message(Command.READY, None)
+        self.client.loop_start()
 
     # THIS FUNCTIONS SIGNATURE MUST NOT BE CHANGED
+    """ Handles the callback if any message arrived """
     def on_message(self, client, data, message):
-        """ Handles the callback if any message arrived """
+        self.msg_queue.append(message)
-        pass
 
-    # Example
+    def subscribetochannel(self, channelname):
-    def send_message(self, topic, message):
+        self.client.subscribe(channelname, qos=1)
-        """ Sends given message to specified channel """
+
-        pass
+    def encode_message(self, msgtype, msgdata):
+        if(msgtype == Command.READY):
+            print("ENC: Case 1")
+            self.msg_queue.append(("explorer/" + self.uid, Command.SEND + Command.READY))
+        if(msgtype == Command.TARGET):
+            print("ENC: Case 2")
+            self.msg_queue.append("explorer/" + self.uid, Command.SEND + Command.TARGET + "reached!")
+        if(msgtype == Command.COMPLETE):
+            print("ENC: Case 3")
+            self.msg_queue.append("explorer/" + self.uid, Command.SEND + Command.COMPLETE)
+        if(msgtype == Command.PATH):
+            print("ENC: Case 4")
+            self.msg_queue.append(("planet/" + self.planetname, Command.SEND + Command.PATH + self.pathtostring(msgdata[0], msgdata[1], msgdata[2])))
+
+    def process_messages(self):
+        for messages in self.msg_queue:
+            if(type(messages) == tuple):
+                print("Sending Message:", messages)
+                self.client.publish(messages[0], payload=messages[1], qos=1)
+            elif(messages.payload.decode('utf-8').startswith(Command.RECEIVE)):
+                print("Received Message:", messages.payload.decode('utf-8'))
+                self.comexec(messages.payload.decode('utf-8')[4:])
+            self.msg_queue.pop(0)
+
+    def comexec(self, message):
+        if not any([message.startswith(instruction) for instruction in Command]):  # is planet name and starting position
+            print("EXEC: Case 1")
+            [self.planetname, startnode] = message.rsplit(' ')
+            self.subscribetochannel(self.planetname)
+            self.planet.setcurnode(str2tuple(*startnode.rsplit(',')))
+        elif message.startswith(Command.PATH):
+            print("EXEC: Case 2")
+            self.stringtopath(*message[5:].rsplit(' '))
+        elif message.startswith(Command.TARGET):
+            print("EXEC: Case 3")
+            self.navto = self.planet.shortest_path(self.planet.getcurnode(), str2tuple(*message[7:].rsplit(',')))
+        elif message.startswith(Command.NOTICE):
+            print("EXEC: Case 4")
+            print(message)
+
+    def stringtopath(self, start, target, block, weight):
+        snode = (str2tuple(*start[:-2].rsplit(',')), str2dir(start[-1:]))
+        tnode = (str2tuple(*target[:-2].rsplit(',')), str2dir(target[-1:]))
+        self.planet.add_path(snode, tnode, int(weight))
+
+    def pathtostring(self, start, target, blocked):
+        if(blocked):
+            path = "blocked"
+        else:
+            path = "free"
+        return tupel2str(*start[0]) + ',' + dir2str(start[1]) + ' ' + tupel2str(*target[0]) + ',' + dir2str(target[1]) + ' ' + path

src/main.py

@@ -19,10 +19,6 @@ def run():
                          clean_session=False,
                          protocol=mqtt.MQTTv31)
 
-    # the execution of all code shall be started from within this function
-    # ADD YOUR OWN IMPLEMENTATION HEREAFTER
-    print("Hello World!")
-
 
 # DO NOT EDIT
 if __name__ == '__main__':

src/move.py

@@ -7,10 +7,13 @@ from sensor import Sensor
 
 class Move:
     def __init__(self, planet):
-        self._wheel_l = Wheel('outB')
+        try:
-        self._wheel_r = Wheel('outC')
+            self._wheel_l = Wheel('outB')
-        self._sensor = Sensor()
+            self._wheel_r = Wheel('outC')
-        self._bumper = ev3.TouchSensor()
+            self._sensor = Sensor()
+            self._bumper = ev3.TouchSensor()
+        except:
+            print("ERROR: Cannot find Motor/Sensor")
 
     '''
     determine maximum and minimum brightness of lines/white space
@@ -42,11 +45,8 @@ class Move:
         self._wheel_l.run()
         self._wheel_r.run()
         while(self._bumper.value() == False):
-#            this does not work... why?
+            self._wheel_l.speed_set(48 - self._sensor.getbrightness())
-#            self._wheel_l.speed_set(ne)
+            self._wheel_r.speed_set(self._sensor.getbrightness())
-#            self._wheel_r.speed_set(newspeed)
-            self._wheel_l._motor.duty_cycle_sp = 48 - self._sensor.getbrightness()
-            self._wheel_r._motor.duty_cycle_sp = self._sensor.getbrightness()
             if(isknownstation == False):
                 pass #run odometry stuff here
         self._wheel_l.stop()

src/planet.py

@@ -45,11 +45,12 @@ formatting example of bidirectional map:
 }
 '''
 
-#Contains the representation of the map and provides certain functions to manipulate it according to the specifications
+# Contains the representation of the map and provides certain functions to manipulate it according to the specifications
 class Planet:
     def __init__(self):
         """ Initializes the data structure """
         self._planetmap = {}
+        self._curnode = None
         self.target = None
 
     # Adds a bidirectional path defined between the start and end coordinates to the map and assigns the weight to it.
@@ -66,6 +67,12 @@ class Planet:
     def get_paths(self) -> Dict[Tuple[int, int], Dict[Direction, Tuple[Tuple[int, int], Direction, Weight]]]:
         return self._planetmap
 
+    def setcurnode(self, node):
+        self._curnode = node
+
+    def getcurnode(self):
+        return self._curnode
+
     '''
     Returns a shortest path between two nodes.
     Used Algorithm: Dijkstra's Algorithm

src/planettest.py

@@ -71,6 +71,7 @@ class YourFirstTestPlanet(unittest.TestCase):
         self.planet.add_path(((1, 0), Direction.NORTH), ((2, 2), Direction.SOUTH), 2)
         self.planet.add_path(((1, 0), Direction.EAST), ((3, 0), Direction.WEST), 1)
         self.planet.add_path(((2, 2), Direction.NORTH), ((2, 3), Direction.SOUTH), 3)
+        self.planet.add_path(((2, 2), Direction.NORTH), ((3, 2), Direction.SOUTH), 1)
         self.planet.add_path(((3, 0), Direction.EAST), ((4, 0), Direction.WEST), -1)
         self.planet.add_path(((3, 2), Direction.NORTH), ((3, 2), Direction.SOUTH), 1)