client-barcode: Add some network error handling

client-barcode/freitagskasse.py

@@ -12,6 +12,7 @@ import sys
 from decimal import Decimal
 import os
 import time
+import urllib2
 
 
 def clear():
@@ -100,20 +101,29 @@ class Status:
 
 	def login(self, auth_blob):
 		assert(not self.logged_in())
+
 		user_name = net.get_user_name_from_auth_blob(auth_blob)
+		balance = net.get_balance(user_name)
+
 		self.auth_blob = auth_blob
 		self.login_name = user_name
-		self.balance = net.get_balance(user_name)
+		self.balance = balance
 		self.transfers = list()
 
 	def commit(self):
 		assert(self.logged_in())
 
 		# Process command queue
-		for (command, balance_backup) in self.transfers:
+		for (command, balance_backup) in list(self.transfers):
+			try:
 				command.run(self.login_name)
-		self.transfers = None
+			except urllib2.HTTPError as e:
+				error_page('FEHLER bei Kommunikation mit Server "%s"' % str(e))
+				break
+			else:
+				self.transfers.pop(0)
 
+		if not self.transfers:
 			# Show final balance for some time
 			clear()
 			self.dump()
@@ -171,12 +181,18 @@ def handle(line, status):
 			item_id = int(line)  # TODO
 			try:
 				item = status.find(item_id)
-			except:  # TODO
+			except urllib2.HTTPError as e:
+				if e.code == 404:  # URL not found == item not found with REST
 					error_page('FEHLER: Aktion oder Ware "%s" nicht bekannt' % line)
+				else:
+					error_page('FEHLER bei Kommunikation mit Server "%s"' % str(e))
 			else:
 				status.buy(item)
 	else:
+		try:
 			status.login(line)
+		except urllib2.URLError as e:
+			error_page('FEHLER bei Kommunikation mit Server "%s"' % e.reason)
 
 
 def main():