replace blockchain.height with height(), and fix server_lag issue

lib/blockchain.py

@@ -30,7 +30,6 @@ class Blockchain(threading.Thread):
         self.config = config
         self.network = network
         self.lock = threading.Lock()
-        self.height = 0
         self.local_height = 0
         self.running = False
         self.headers_url = 'http://headers.electrum.org/blockchain_headers'
@@ -38,6 +37,10 @@ class Blockchain(threading.Thread):
         self.queue = Queue.Queue()
 
     
+    def height(self):
+        return self.local_height
+
+
     def stop(self):
         with self.lock: self.running = False
 
@@ -80,7 +83,9 @@ class Blockchain(threading.Thread):
                 chain = self.get_chain( i, header )
 
                 # skip that server if the result is not consistent
-                if not chain: continue
+                if not chain: 
+                    print_error('e')
+                    continue
                 
                 # verify the chain
                 if self.verify_chain( chain ):
@@ -93,9 +98,7 @@ class Blockchain(threading.Thread):
                     continue
 
 
-            if self.height != height:
-                self.height = height
-                self.network.new_blockchain_height(height, i)
+            self.network.new_blockchain_height(height, i)
 
 
                     
@@ -253,7 +256,6 @@ class Blockchain(threading.Thread):
             h = os.path.getsize(name)/80 - 1
             if self.local_height != h:
                 self.local_height = h
-                self.height = self.local_height
 
 
     def read_header(self, block_height):

lib/network.py

@@ -198,7 +198,7 @@ class Network(threading.Thread):
                 self.switch_to_random_interface()
             else:
                 if self.server_lag > 0:
-                    self.interface.stop()
+                    self.stop_interface()
         else:
             self.set_server(server)
 
@@ -208,18 +208,23 @@ class Network(threading.Thread):
             self.switch_to_interface(random.choice(self.interfaces.values()))
 
     def switch_to_interface(self, interface):
+        assert self.interface is None
         server = interface.server
         print_error("switching to", server)
         self.interface = interface
         h =  self.heights.get(server)
         if h:
-            self.server_lag = self.blockchain.height - h
+            self.server_lag = self.blockchain.height() - h
         self.config.set_key('server', server, False)
         self.default_server = server
         self.send_subscriptions()
         self.trigger_callback('connected')
 
 
+    def stop_interface(self):
+        self.interface.stop() 
+        self.interface = None
+
     def set_server(self, server):
         if self.default_server == server and self.interface:
             return
@@ -229,7 +234,7 @@ class Network(threading.Thread):
 
         # stop the interface in order to terminate subscriptions
         if self.interface:
-            self.interface.stop() 
+            self.stop_interface()
 
         # notify gui
         self.trigger_callback('disconnecting')
@@ -255,6 +260,7 @@ class Network(threading.Thread):
 
 
     def new_blockchain_height(self, blockchain_height, i):
+        print_error('new_blockchain_height')
         if self.is_connected():
             h = self.heights.get(self.interface.server)
             if h:
@@ -263,6 +269,8 @@ class Network(threading.Thread):
                     print_error( "Server is lagging", blockchain_height, h)
                     if self.config.get('auto_cycle'):
                         self.set_server(i.server)
+            else:
+                print_error('no height for main interface')
         
         self.trigger_callback('updated')
 
@@ -304,11 +312,17 @@ class Network(threading.Thread):
     def on_header(self, i, r):
         result = r.get('result')
         if not result: return
-        self.heights[i.server] = result.get('block_height')
+        height = result.get('block_height')
+        self.heights[i.server] = height
+        # notify blockchain about the new height
         self.blockchain.queue.put((i,result))
 
         if i == self.interface:
-            self.server_lag = self.blockchain.height - self.heights[i.server]
+            self.server_lag = self.blockchain.height() - height
+            if self.server_lag > 1 and self.config.get('auto_cycle'):
+                print_error( "Server lagging, stopping interface")
+                self.stop_interface()
+
             self.trigger_callback('updated')