Mailman 3 May 2003 - Twisted

[Twisted-Python] Safe Pickling using banana and jelly
by Heiko Wundram 28 May '03

28 May '03

Hi to all! Maybe this question has been answered elsewhere, but it doesn't seem to be stated anywhere in the Twisted HOWTO's or any other documentation safe the overall stance that jelly and banana are "replacements for pickle aimed at safety, not speed": Is unpickling _untrusted_ network data using banana and jelly a safe thing? After a length check on the data has been done, discarding all messages that are over 50k in size, of course... :) Thanks for any reply. :) Heiko.

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[Twisted-Python] SNMP in Twisted
by Wari Wahab 28 May '03

28 May '03

I was given the task to have a program to send SNMP get requests and recieve SNMP traps. There is a PySNMP package out there, and I guess that it's a blocking call to get data from an SNMP server, especially when doing a walk style request. My questions are, 1. Should one attempt on doing the hair raising task of doing the SNMP client and Server protocols? (Hopefully, you should never need to write your own protocols) 2. Use the PySNMP library as is, no matter how blocking that can be? 3. Use PySNMP calls in a thread? 4. Use the command line executables of ucd-snmp (or net-snmp) and use the reactor.spawnProcess() calls. Get SNMP traps using syslog named pipes. All are valid answers, though I pretty much think that 1. is the best way to go, BUT, looking at SNMP rfcs, it could very well prove to be an almost impossible task (especially for a newbie like me:).

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[Twisted-Python] web forms and authentication in LDAP server
by Kaloian Doganov 28 May '03

28 May '03

Hello! I have two short twisted-newbie questions: Is there any kind of documentation (instead of the API docs) that I can read about how to use twisted.web.woven.form package? Any kind of example would be appreciated. Does anyone work on adding LDAP support for twisted.cred? I am interested in writing such module, once I get more experienced with Twisted. Best Regards, Kaloian Doganov.

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[Twisted-Python] XMLRPC getting calling host
by Heiko Wundram 27 May '03

27 May '03

Hey there! Just a little try to check whether I'm still subscribed to twisted, as today's other posts regarding the safe pickling never got through, somehow... I've come to the point where I need to query the IP an XMLRPC request came from. In UDP, you get it served when the call to datagramReceived comes through, but I've not seen any attribute of the XMLRPC class, or of the underlying Resource class which states anything about how to get this attribute. Is it possible? And if, how? Thanks! Heiko.

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[Twisted-Python] toc.py
by Konrad Rokicki 27 May '03

27 May '03

Hey, Is there any reason TOCClient doesnt catch exceptions made by callbacks? Shouldn't line 902 look something like this (modeled after IRCClient): try: func(l) except: log.deferr() Or maybe it should go somewhere else, but I don't think it should disconnect when an exception isn't caught. Also, what are the TOC and IRC classes for? I'm trying to do certain things with TOCClient (i.e. user info) that only seem to be in TOC.. Thanks, Konrad

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[Twisted-Python] sshclient and sshserver examples
by Selwyn McCracken 27 May '03

27 May '03

hi, I am trying to run the sshsimpleclient.py from the CVS examples folder. However I get the following error. Traceback (most recent call last): File "/home/selwyn/.ssh/sshClient.py", line 44, in ? class TrueChannel(connection.SSHChannel): AttributeError: 'module' object has no attribute 'SSHChannel' rummaging around in connection, there doesn't appear to be the appropriate class available. Help greatly appreciated. Selwyn

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[Twisted-Python] Woven using wrong model adapter
by Kevin Turner 27 May '03

27 May '03

I have: components.registerAdapter(model.ObjectWrapper, interests.InterestChangeReport, wovenInterfaces.IModel) class Page(page.Page): def wmfactory_report(self, request): if sometimes: return deferredInterestChangeReport() else: return '' If the first page I serve after starting the server gets an InterestChangeReport, then everything works just fine. However, if the first page served gets '', then any future page that gets an InterestChangeReport dies with an exception: "the submodel was not found in [<twisted.web.woven.model.StringModel instance at 0x85167c4: wrapped data: <InterestChangeReport instance...>" So why does woven persist in using the StringModel adapter in this case, and how can I get it to stop? Don't know if this is related or not, but the log shows messages like: "Warning: There was no parent for node [...]; node not mutated." Is that something I should be concerned about? Thanks, - Kevin -- The moon is waning crescent, 16.8% illuminated, 25.6 days old.

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[Twisted-Python] Small diff for LivePage controller
by Bill Gribble 27 May '03

27 May '03

Hi. I noticed that when my LivePage instance sends updates to DOM elements that are whitespace-sensitive, such as <pre> and <textarea wordwrap="off>, embedded newlines were getting stripped, leaving the element bodies as single text lines with some interword spacing removed. I tracked the problem down to this bit of code in woven/controller.py. The Javascript code generator is formatting the new element as a literal Javascript string which will be processed on the client side to modify the page. But by stripping out the newlines in the code we remove some important information in some HTML contexts. This patch leaves embedded newlines in the text, using JavaScript literal string escapes to make sure they get passed through OK. I also added string escaping for other legal special characters that have JS literal escapes. With this patch, LivePage is working really well for me! Thanks to all the folks who have given help on IRC. FWIW this patch is in the public domain. Bill Gribble Index: controller.py =================================================================== RCS file: /cvs/Twisted/twisted/web/woven/controller.py,v retrieving revision 1.60 diff -r1.60 controller.py 368,369d367 < nodeXML = nodeXML.replace('\n', '') < nodeXML = nodeXML.replace('\r', '') 371a370,378 > nodeXML = nodeXML.replace('"', '\\"') > nodeXML = nodeXML.replace('\n', '\\n') > nodeXML = nodeXML.replace('\r', '\\r') > nodeXML = nodeXML.replace('\b', '\\b') > nodeXML = nodeXML.replace('\t', '\\t') > nodeXML = nodeXML.replace('\000', '\\0') > nodeXML = nodeXML.replace('\v', '\\v') > nodeXML = nodeXML.replace('\f', '\\f') >

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[Twisted-Python] Using usage.Options documentation error
by pobrien＠orbtech.com 27 May '03

27 May '03

There appears to be an error in the code example on this page: http://www.twistedmatrix.com/documents/howto/options <quote> Inheritance, Or: How I Learned to Stop Worrying and Love the Superclass Sometimes there is a need for several option processors with a unifying core. Perhaps you want all your commands to understand -q/--quiet means to be quiet, or something similar. On the face of it, this looks impossible: in Python, the subclass's optFlags would shadow the superclass's. However, usage.Options uses special reflection code to get all of the optFlags defined in the hierarchy. So the following: class BaseOptions(usage.Options): optFlags = [["quiet", "q"], None] class SpecificOptions(BaseOptions): optFlags = [ ["fast", "f", None], ["good", "g", None], ["cheap", "c", None] ] Is the same as: class SpecificOptions(BaseOptions): optFlags = [ ["quiet", "q", "Silence output"], ["fast", "f", "Run quickly"], ["good", "g", "Don't validate input"], ["cheap", "c", "Use cheap resources"] ] </quote> I don't see how the descriptions in the second SpecificOptions class match with the use of None in the first set of classes. Twisted is good, but it isn't *that* good, is it? -- Patrick K. O'Brien Orbtech http://www.orbtech.com/web/pobrien ----------------------------------------------- "Your source for Python programming expertise." -----------------------------------------------

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[Twisted-Python] bug and patch: embedded LivePages
by Mario Ruggier 27 May '03

27 May '03

Hi, in the case when a LivePage happens to be itself the contents of an iframe, the input web conduit does not work as it attempts to execute js from "top". It should be "parent". To test, place the following script next to any LivePage example (such as the dhtmlLivePage.rpy posted some days ago by Donovan Preston): iframed_dhtmlLivePage.rpy: ================================ from twisted.web.woven import page resource = page.Page() resource.template = '''<html> <body style="margin:1em; background-color: gray;"> <iframe style="width: 80%; padding: 1em;" src="../dhtmlLivePage"> iframe contents </iframe> </body> </html> ''' ================================ The diff w.r.t. cvs version of twisted/web/woven/controller.py: ================================ --- twisted/web/woven/controller.py Tue May 27 10:58:55 2003 +++ twisted/web/woven/controller.py Sat May 24 12:26:22 2003 @@ -333,7 +333,7 @@ target.onEvent(request, eventName, *eventArgs) sess.sendScript = orig - scriptOutput.append('parent.woven_clientToServerEventComplete()') + scriptOutput.append('top.woven_clientToServerEventComplete()') #print "GATHERED JS", scriptOutput @@ -369,7 +369,7 @@ nodeXML = nodeXML.replace('\r', '') nodeXML = nodeXML.replace("\\", "\\\\") nodeXML = nodeXML.replace("'", "\\'") - js = "parent.woven_replaceElement('%s', '%s')" % (nodeId, nodeXML) + js = "top.woven_replaceElement('%s', '%s')" % (nodeId, nodeXML) #for key in widget.subviews.keys(): # view.subviews[key].unlinkViews() oldNode = page.view.subviews[nodeId] ================================ cheers, mario

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Twisted May 2003