Fixed: Simple Codacy errors and warnings in src/helper_*

* Some local pickle operations and non-cryptographic random operations
were marked as safe to the bandit linter
 * A bandit config file was added and assert warnings are now ignored globally
 * Tightened up exception handling and code style

bandit.yml

@@ -0,0 +1,4 @@
+# Codacy uses Bandit.
+
+# Asserts are accepted throughout the project.
+skips: ['B101']

src/helper_bootstrap.py

@@ -1,6 +1,6 @@
 import socket
 import defaultKnownNodes
-import pickle
+import pickle  # nosec
 import time
 
 from bmconfigparser import BMConfigParser
@@ -24,7 +24,7 @@ def knownNodes():
     try:
         with open(state.appdata + 'knownnodes.dat', 'rb') as pickleFile:
             with knownnodes.knownNodesLock:
-                knownnodes.knownNodes = pickle.load(pickleFile)
+                knownnodes.knownNodes = pickle.load(pickleFile)  # nosec
             # the old format was {Peer:lastseen, ...}
             # the new format is {Peer:{"lastseen":i, "rating":f}}
             for stream in knownnodes.knownNodes.keys():

src/helper_msgcoding.py

@@ -140,7 +140,6 @@ class MsgDecode(object):
         self.body = body
 
 if __name__ == '__main__':
-    import random
     messageData = {
         "subject": ''.join(helper_random.randomchoice(string.ascii_lowercase + string.digits) for _ in range(40)),
         "body": ''.join(helper_random.randomchoice(string.ascii_lowercase + string.digits) for _ in range(10000))

src/helper_random.py

@@ -1,3 +1,5 @@
+"""Convenience functions for random operations. Not suitable for security / cryptography operations."""
+
 import os
 import random
 from pyelliptic.openssl import OpenSSL
@@ -48,9 +50,9 @@ def randomrandrange(x, y=None):
     but doesnt actually build a range object.
     """
     if isinstance(y, NoneType):
-        return random.randrange(x)
+        return random.randrange(x)  # nosec
     else:
-        return random.randrange(x, y)
+        return random.randrange(x, y)  # nosec
 
 
 def randomchoice(population):
@@ -60,4 +62,4 @@ def randomchoice(population):
     sequence seq. If seq is empty, raises
     IndexError.
     """
-    return random.choice(population)
+    return random.choice(population)  # nosec

src/helper_search.py

@@ -5,7 +5,7 @@ from helper_sql import *
 try:
     from PyQt4 import QtGui
     haveQt = True
-except Exception:
+except ImportError:
     haveQt = False
 
 def search_translate (context, text):

src/helper_sql.py

@@ -91,6 +91,7 @@ class SqlBulkExecute:
     def execute(sqlStatement, *args):
         """Used for statements that do not return results."""
         sqlSubmitQueue.put(sqlStatement)
+
         if args == ():
             sqlSubmitQueue.put('')
         else:

src/helper_startup.py

@@ -113,7 +113,8 @@ def loadConfig():
         BMConfigParser().set('bitmessagesettings', 'maxuploadrate', '0')
         BMConfigParser().set('bitmessagesettings', 'maxoutboundconnections', '8')
         BMConfigParser().set('bitmessagesettings', 'ttl', '367200')
-         #start:UI setting to stop trying to send messages after X days/months
+
+        #start:UI setting to stop trying to send messages after X days/months
         BMConfigParser().set(
             'bitmessagesettings', 'stopresendingafterxdays', '')
         BMConfigParser().set(