add and use Reject exception [SF#700265]

Author: Richard Jones

CHANGES.txt

@@ -7,12 +7,16 @@ Feature:
 - added new auditor, emailauditor.py, that works around a bug in IE. See 
   emailauditor.py for more info.
 - added dispatcher functionality - see upgrading.txt for more info
+- added Reject exception which may be raised by auditors. This is trapped
+  by mailgw and may be used to veto creation of file attachments or
+  messages. (sf bug 700265)
 
 Fixed:
 - Boolean HTML templating was broken
 - Link HTML templating field() was broken
 - Fix reporting of test inclusion in postgresql test
 
+
 2004-03-24 0.7.0b1
 Major new features:
 - added postgresql backend (originally from sf patch 761740, many changes

doc/customizing.txt

@@ -2,7 +2,7 @@
 Customising Roundup
 ===================
 
-:Version: $Revision: 1.122 $
+:Version: $Revision: 1.123 $
 
 .. This document borrows from the ZopeBook section on ZPT. The original is at:
    http://www.zope.org/Documentation/Books/ZopeBook/current/ZPT.stx
@@ -586,6 +586,37 @@ to use one, copy it to the ``'detectors'`` of your tracker instance:
         db.issue.react('create', newissuecopy)
 
 
+Auditor or Reactor?
+-------------------
+
+Generally speaking, the following rules should be observed:
+
+**Auditors**
+  Are used for `vetoing creation of or changes to items`_. They might
+  also make automatic changes to item properties.
+**Reactors**
+  Detect changes in the database and react accordingly. They should avoid
+  making changes to the database where possible, as this could create
+  detector loops.
+
+Vetoing creation of or changes to items
+---------------------------------------
+
+Auditors may raise the ``Reject`` exception to prevent the creation of
+or changes to items in the database.  The mail gateway, for example, will
+not attach files or messages to issues when the creation of those files or
+messages are prevented through the ``Reject`` exception. It'll also not create
+users if that creation is ``Reject``'ed too.
+
+To use, simply add at the top of your auditor::
+
+   from roundup.exceptions import Reject
+
+And then when your rejection criteria have been detected, simply::
+
+   raise Reject
+
+
 Database Content
 ================
 

roundup/cgi/actions.py

@@ -1,3 +1,5 @@
+#$Id: actions.py,v 1.15 2004-03-26 00:44:11 richard Exp $
+
 import re, cgi, StringIO, urllib, Cookie, time, random
 
 from roundup import hyperdb, token, date, password, rcsv
@@ -837,3 +839,4 @@ def handle(self):
 
         return '\n'
 
+# vim: set filetype=python ts=4 sw=4 et si

roundup/cgi/exceptions.py

@@ -1,3 +1,9 @@
+#$Id: exceptions.py,v 1.4 2004-03-26 00:44:11 richard Exp $
+'''Exceptions for use in Roundup's web interface.
+'''
+
+__docformat__ = 'restructuredtext'
+
 import cgi
 
 class HTTPException(Exception):
@@ -51,3 +57,4 @@ def __str__(self):
 </body></html>
 '''%cgi.escape(self.args[0])
 
+# vim: set filetype=python ts=4 sw=4 et si

roundup/exceptions.py

@@ -0,0 +1,19 @@
+#$Id: exceptions.py,v 1.1 2004-03-26 00:44:11 richard Exp $
+'''Exceptions for use across all Roundup components.
+'''
+
+__docformat__ = 'restructuredtext'
+
+class Reject(Exception):
+    '''An auditor may raise this exception when the current create or set
+    operation should be stopped.
+
+    It is up to the specific interface invoking the create or set to
+    handle this exception sanely. For example:
+
+    - mailgw will trap and ignore Reject for file attachments and messages
+    - cgi will trap and present the exception in a nice format
+    '''
+    pass
+
+# vim: set filetype=python ts=4 sw=4 et si

roundup/mailgw.py

@@ -72,15 +72,15 @@ class node. Any parts of other types are each stored in separate files
 an exception, the original message is bounced back to the sender with the
 explanatory message given in the exception. 
 
-$Id: mailgw.py,v 1.145 2004-03-25 22:52:12 richard Exp $
+$Id: mailgw.py,v 1.146 2004-03-26 00:44:11 richard Exp $
 """
 __docformat__ = 'restructuredtext'
 
 import string, re, os, mimetools, cStringIO, smtplib, socket, binascii, quopri
 import time, random, sys
 import traceback, MimeWriter, rfc822
 
-from roundup import hyperdb, date, password, rfc2822
+from roundup import hyperdb, date, password, rfc2822, exceptions
 from roundup.mailer import Mailer
 
 SENDMAILDEBUG = os.environ.get('SENDMAILDEBUG', '')
@@ -805,8 +805,13 @@ def handle_message(self, message):
             for (name, mime_type, data) in attachments:
                 if not name:
                     name = "unnamed"
-                files.append(self.db.file.create(type=mime_type, name=name,
-                                                 content=data, **file_props))
+                try:
+                    fileid = self.db.file.create(type=mime_type, name=name,
+                         content=data, **file_props)
+                except exceptions.Reject:
+                    pass
+                else:
+                    files.append(fileid)
             # attach the files to the issue
             if nodeid:
                 # extend the existing files list
@@ -821,20 +826,23 @@ def handle_message(self, message):
         # create the message if there's a message body (content)
         #
         if (content and properties.has_key('messages')):
-            message_id = self.db.msg.create(author=author,
-                recipients=recipients, date=date.Date('.'), summary=summary,
-                content=content, files=files, messageid=messageid,
-                inreplyto=inreplyto, **msg_props)
-
-            # attach the message to the node
-            if nodeid:
-                # add the message to the node's list
-                messages = cl.get(nodeid, 'messages')
-                messages.append(message_id)
-                props['messages'] = messages
+            try:
+                message_id = self.db.msg.create(author=author,
+                    recipients=recipients, date=date.Date('.'),
+                    summary=summary, content=content, files=files,
+                    messageid=messageid, inreplyto=inreplyto, **msg_props)
+            except exceptions.Reject:
+                pass
             else:
-                # pre-load the messages list
-                props['messages'] = [message_id]
+                # attach the message to the node
+                if nodeid:
+                    # add the message to the node's list
+                    messages = cl.get(nodeid, 'messages')
+                    messages.append(message_id)
+                    props['messages'] = messages
+                else:
+                    # pre-load the messages list
+                    props['messages'] = [message_id]
 
         #
         # perform the node change / create
@@ -948,10 +956,13 @@ def uidFromAddress(db, address, create=1, **user_props):
             trying = username + str(n)
 
         # create!
-        return db.user.create(username=trying, address=address,
-            realname=realname, roles=db.config.NEW_EMAIL_USER_ROLES,
-            password=password.Password(password.generatePassword()),
-            **user_props)
+        try:
+            return db.user.create(username=trying, address=address,
+                realname=realname, roles=db.config.NEW_EMAIL_USER_ROLES,
+                password=password.Password(password.generatePassword()),
+                **user_props)
+        except exceptions.Reject:
+            return 0
     else:
         return 0