Better error handling (including for EAGAIN)

telematica/ass1/async.py

@@ -4,6 +4,10 @@ import re
 import random
 from asyncbase import AsyncBase
 
+# Socket error "Resource temporarily unavailable": try again ;)
+EAGAIN = 11
+
+
 class ClientConnection(object, AsyncBase, asyncore.dispatcher):
 
     def __init__(self):
@@ -53,9 +57,26 @@ class ClientConnection(object, AsyncBase, asyncore.dispatcher):
 
     def handle_error(self):
         if hasattr(self, 'main'):
-            self.main.execute('disconnect')
-            self.main.display_info('Error raised due to a broken or refused'\
-                    + ' connection')
+            import sys
+            t, v, tb = sys.exc_info()
+            tbinfo = []
+            while tb:
+                tbinfo.append((
+                    tb.tb_frame.f_code.co_filename,
+                    tb.tb_frame.f_code.co_name,
+                    str(tb.tb_lineno)
+                    ))
+                tb = tb.tb_next
+
+            file, function, line = tbinfo[-1]
+            info = ' '.join(['[%s|%s|%s]' % x for x in tbinfo])
+            self.debug_log('Exception raised in "%s" (%s line %s). Traceback:' \
+                    % (function, file, line))
+            self.debug_log(info)
+            self.main.display_info(str(v))
+            #self.main.execute('disconnect')
+            #self.main.display_info('Error raised due to a broken or refused'\
+            #        + ' connection')
 
     def handle_close(self):
         self.close()
@@ -67,7 +88,18 @@ class ClientConnection(object, AsyncBase, asyncore.dispatcher):
 
         # Receive a (multiline) message.
         while True:
-            chunk = self.recv(1)
+            try:
+                chunk = self.recv(1)
+            except socket.error, e:
+                # Suppress "Resource temporarily unavailable" exceptions.
+                if e.errno == EAGAIN:
+                    # Wait 5 ms
+                    import time
+                    time.sleep(0.005)
+                    continue
+                else:
+                    raise
+
             if not chunk:
                 raise RuntimeError('socket connection broken')
             if chunk in ['-','+']:
@@ -77,7 +109,6 @@ class ClientConnection(object, AsyncBase, asyncore.dispatcher):
             elif chunk == '\n' and buf[-1] == '\r':
                 if not multi_line:
                     break
-                self.debug_log('receiving multi line response...')
                 if buf[-3:] == '\r\n\r':
                     # Remove trailing '\n\r' from multi line response
                     buf = buf[:-2]
@@ -131,9 +162,8 @@ class ClientConnection(object, AsyncBase, asyncore.dispatcher):
         # After authentification, fetch the list of users currently logged in.
         if not self.retrieved_user_list:
             if not self.request_user_list_sent:
-                #self.request_user_list_sent = True
-                #self.retrieve_users()
-                pass
+                self.request_user_list_sent = True
+                self.retrieve_users()
             else:
                 # TODO: process user list
                 self.retrieved_user_list = True
@@ -153,5 +183,5 @@ class ClientConnection(object, AsyncBase, asyncore.dispatcher):
 
 if __name__ == '__main__':
     client = ClientConnection()
-    client.connect(('ow150.science.uva.nl', 16897))
+    client.connect(('localhost', 16897))
     client.init_loop()

telematica/ass1/cli.py

@@ -162,7 +162,6 @@ class CLI:
             self.display_info('Offline. Type "/connect HOST" to connect' \
                     + ' to another chat server.')
             self.info_bar.prefix('')
-            self.debug_window.clear()
             self.refresh()
 
         def help(main):

telematica/ass1/server.py

@@ -190,8 +190,9 @@ class RequestHandler(AsyncBase, asyncore.dispatcher):
             return self.send_all('SAY %s/%s' % (self.username, buf[4:]))
         if cmd == 'NAMES':
             self.send_raw('+Ok:')
-            for c in self.server.clients:
-                self.send_raw(self.server.clients[c].username)
+            clients = self.server.clients
+            for c in clients:
+                self.send_raw(clients[c].username)
             self.send_raw('')
             return True
         return self.send_negative('Unsupported command.')