nodes now broadcast a timestamp of their last change

main.py

@@ -3,23 +3,23 @@
 import socket, os, time, select, urllib, sys, threading 
 
 class Meshenger:
-  devices = [] #the list of all the nodes this this node has seen
+  devices = {} #the dictionary of all the nodes this this node has seen
   serve_port = 13338
   announce_port = 13337
   #own_ip = "0.0.0.0"
   msg_dir = os.path.relpath('msg/')
   exitapp = False #to kill all threads on
+  index_last_update = ''
 
 
   def __init__(self):
 
-    os.system("echo 1 >> /proc/sys/net/ipv6/conf/br-lan/disable_ipv6")
+    #os.system("echo 1 >> /proc/sys/net/ipv6/conf/br-lan/disable_ipv6")
     self.own_ip = self.get_ip_adress()
-    #self.own_ip = "192.168.2.196"
-
+    print 'Building own index for the first time\n'
+    self.build_index()
 
     try:
-      #print 'discovering devices'
       d = threading.Thread(target=self.discover)
       d.daemon = True
       d.start()
@@ -38,26 +38,39 @@ class Meshenger:
 
       if len(self.devices) > 0:
         print 'found', len(self.devices),'device(s) retreiving indices'
-        for device in self.devices:
-          nodepath = self.ip_to_hash(device)
-
-          self.get_index(device, nodepath)
 
-          self.get_messages(device, nodepath)
-          print 'updating own index'
-          self.build_index()
+        for device in self.devices:
+          nodepath = self.ip_to_hash(device)  #make a folder for the node (nodes/'hash'/)
+          nodeupdatepath = self.node_timestamp(device, nodepath) #contains the path to the update timestamp of the node (nodes/'hash'/lastupdate)
+
+          print 'Checking age of foreign node index'
+          if self.devices[device] > nodeupdatepath:
+            print 'Foreign node"s index is newer, proceed to download index' 
+            self.get_index(device, nodepath)
+            print 'downloading messages'
+            self.get_messages(device, nodepath)
+            print 'updating own index'
+            self.build_index()
           
       time.sleep(5) #free process or ctrl+c
  
+  def node_timestamp(self, ip, path):
+
+      updatepath = os.path.join(path, 'lastupdate')
+      with open(updatepath, 'wb') as lastupdate:
+        lastupdate.write(self.devices[ip])
+      return updatepath
+
+
 
   def announce(self):
     """
     Announce the node's existance to other nodes
     """
+    print 'Announcing'
     while not self.exitapp:
-      print 'announcing'
       sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
-      sock.sendto('bericht', ("ff02::1", self.announce_port))
+      sock.sendto(self.index_last_update, ("ff02::1", self.announce_port))
       sock.close()
       time.sleep(5)
 
@@ -66,20 +79,19 @@ class Meshenger:
     Discover other devices by listening to the Meshenger announce port
     """
 
+    print 'Discovering'
     bufferSize = 1024 # whatever you need
 
     s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
     s.bind(('::', self.announce_port))
     s.setblocking(0)
 
-    #global devices
-
     while not self.exitapp:
-      print 'discovering'
       result = select.select([s],[],[])[0][0].recvfrom(bufferSize)
       if result[1][0] not in self.devices and result[1][0] != self.own_ip:
-        self.devices.append(result[1][0])
-        return
+        self.devices[result[1][0]] = result[0][0]
+        #self.devices.append(result[1][0])
+
       time.sleep(1)
 
   def serve(self):
@@ -111,8 +123,11 @@ class Meshenger:
         for message in os.listdir(self.msg_dir):
           index.write(message)
           index.write('\n')
-      with open('index_last_update', 'wb') as indexupdate:
+      self.index_last_update = str(int(time.time()))
+
+      with open('index_last_update', 'wb') as indexupdate: ### misschien is dit overbodig
         indexupdate.write(str(int(time.time())))
+
       current_index = previous_index
 
   def get_index(self,ip, path):
@@ -161,7 +176,6 @@ class Meshenger:
     """
     if not os.path.isfile('interfaceip6adress'):
       os.system('ifconfig -a adhoc0 | grep inet6 > interfaceip6adress')
-
     with open('interfaceip6adress', 'r') as a:
       return a.read().split()[2].split('/')[0]