Mailman 3 June 2003 - Twisted

[Twisted-Python] Woven newby question
by rdrb＠123.cl 24 Jun '03

24 Jun '03

I have tried different formulas but I still not guessing how to use the Widget Paragraph text in order to show a StringModel as "line1line2line3" html. This should be trivial but I do not get it. Could some one help me? Thanks. Rodrigob.

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[Twisted-Python] Metakit and Twisted ??
by Thomas Weholt ( PRIVAT ) 24 Jun '03

24 Jun '03

Has anybody tried to use Metakit with Twisted? Is there anyway to avoid blocking using Metakit, using Deferred etc. ?? Best regards, Thomas Weholt

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[Twisted-Python] Setting up a HTTPS-server
by Thomas Weholt ( PRIVAT ) 24 Jun '03

24 Jun '03

Can anybody tell me how or if Twisted supports HTTPS? I've used M2Crypto in the past ad saw that the latest release also supports secure FTP. I'm not clear on the status of the current FTP-implementation in Twisted, so if anybody would like to shed some light on the current status of HTTPS and secure FTP that would be great. ( Any information on how to implement a simple authenticating FTP server running alongside a HTTP(S)-server would also be cool. ) Regards, Thomas Weholt

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[Twisted-Python] Subclassing Resource, problems accessing persistent data/using registry
by Thomas Weholt 24 Jun '03

24 Jun '03

I've subclassed twisted.web.resource to create my own type of rpys where the content is wrapped in a site-wide template before being returned to the client. This makes it easier and quicker to generate content in the rpys themselves. I've also created a response-object instead of returning just a string from the render-method or using request.write. IMHO a server should work with a response to a request, not use the request itself to send content back to the client. The code in the bottom of the posting works great ( making it into a rpy, running mktap + twistd etc. ), but if I create a rpy file called test.rpy, with something like : --------------------- snip snip -------------------------------------------------- from hs.twisted.eloperesource import ElopeRespource class test(ElopeRespource): def content(self, request, response, server): response.add('hello world, once again') resource = test() --------------------- snip snip -------------------------------------------------- I cannot get the persistent data in my custom server-class to be registered, the registry.getComponent-method is not available. Can I register persistent data in any other way and somehow pass it to my own rpys? How can I manually register persistent data, not use the automagical-way in rpys? I create a web.tap file and try to serve the data using twisted -f web.tap etc. but it raises an exception. Any hint, idea, flame or constructive comment would be appreciated. Best regards, Thomas W --------------------- snip snip -------------------------------------------------- import os, types, sys, cgi, time, string, cStringIO, gzip, traceback, PyMeld from twisted.web import server, resource from twisted.internet import reactor from twisted.web import server, resource, error from twisted.protocols import http from twisted.web.static import File from twisted.internet import reactor # special custom classes from hs.twisted.response import response from hs.twisted.Server import Server server = registry.getComponent(Server) if not server: registry.setComponent(Server, Server()) server = registry.getComponent(Server) class ElopeResource(resource.Resource): isLeaf = True def __init__(self): resource.Resource.__init__(self) def content(self, request, response, server): # Should be overridden by the rpy response.add('Should be overridden') # added content is accumulated in the response-object def render(self, request): resp = response() self.content(request, resp, server) if resp.filename and not resp.content_type in ['text/xml', 'text/plain', 'text/html', 'text/css']: # special handler to return files not directly available online, located somewhere on local filesystem filesize = os.stat(resp.filename)[6] modification_time = os.stat(resp.filename)[8] request.setHeader("Content-Length", filesize) request.setHeader("Last-modified", time.ctime(modification_time)) request.setHeader("Content-Disposition", 'file; filename="%s"' % os.path.split(resp.filename)[1]) return File(resp.filename, getContentType(resp.filename)).render(request) elif resp.url: request.redirect(resp.url) return 'You should be redirect to %s' % resp.url else: if resp.filename: # a plain-text, html or xml-file resp.content = open(resp.filename).read() request.setResponseCode(resp.response_code, 'OK') request.setHeader("Content-type", resp.content_type) if request.received_headers.has_key('accept-encoding'): # custom gzip-encoding if 'gzip' in map(string.strip, request.received_headers['accept-encoding'].split(',')) and \ resp.content_type in ['text/xml', 'text/plain', 'text/html', 'text/css']: try: fd = cStringIO.StringIO() gz = gzip.GzipFile(filename='', mode='wb', compresslevel=9, fileobj=fd) resp.content = '<html><body>%s</body></html>' % resp.content gz.write(resp.content) gz.close() gzHtml = fd.getvalue() request.setHeader("Content-Length", len(gzHtml)) request.setHeader("Content-Encoding", 'gzip') return gzHtml except: fp = cStringIO.StringIO() traceback.print_exc(file=fp) content = fp.getvalue() return self.templates.populateSceleton(content, 'default') else: content = '<html><body>%s</body></html>' % resp.content request.setHeader("Content-Length", len(content)) return content class Simple(ElopeResource): def content(self, request, response, server): response.add('Hello world! And there\'s even some persistent data from the server : %s' % vars(server)) server.data['time'] = time.ctime(time.time()) resource = Simple()

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[Twisted-Python] Interactive control of client?
by Joel Boehland 24 Jun '03

24 Jun '03

Hi, I'm fairly new to Twisted, so this may be a stupid question, but that's never stopped me before! :-) Anyhow, I would like to be able to script a tcp client to play around with sending different protocol elements from within the python interpreter. To boil it down to a super-simple example I'll take the EchoClient example. Is there anyway to get a handle to that client and have it send different strings to the EchoServer. I'm imagining being able to do something like this in the python interpreter: >>>echoclient = SomeWayToGetClient(...) >>>echoclient.sendLine("blah") >>>echoclient.sendLine("bleh") I'm assuming I would have to have the client run in another thread to be able to allow the python interpreter thread to run as well, but I'm not sure how I would do that. Any Info/help appreciated! cheers, Joel Boehland

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[Twisted-Python] Q: PyQt and error handling in Deferreds
by Egor Cheshkov 24 Jun '03

24 Jun '03

Hello! I'm writing client application using Twisted and PyQt. I want to handle connection errors by showing the message box that describes it, so my errback looks like this: def _ebSessionRequest(self, err): QMessageBox.critical(self, "Warder", "Can't connect to server.") self.setEnabled(1) self.editAccesCode.setFocus() It works nice but when the errback fired i get two tracebacks: Traceback (most recent call last): File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 215, in errback self._startRunCallbacks(fail, 1) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 249, in _startRunCallbacks self._runCallbacks() File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 262, in _runCallbacks self.result = callback(self.result, *args, **kw) File "main.py", line 185, in _ebSessionRequest QMessageBox.critical(self, "Warder", "Can't connect to server.") --- <exception caught here> --- File "/usr/lib/python2.2/site-packages/twisted/internet/qtreactor.py", line 74, in read why = w.doRead() File "/usr/lib/python2.2/site-packages/twisted/internet/tcp.py", line 378, in doConnect self.failIfNotConnected(error.getConnectError((connectResult, os.strerror(connectResult)))) File "/usr/lib/python2.2/site-packages/twisted/internet/tcp.py", line 315, in failIfNotConnected self.connector.connectionFailed(failure.Failure(err)) File "/usr/lib/python2.2/site-packages/twisted/internet/base.py", line 527, in connectionFailed self.factory.clientConnectionFailed(self, reason) File "/usr/lib/python2.2/site-packages/twisted/web/xmlrpc.py", line 209, in clientConnectionLost self.deferred.errback(reason) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 215, in errback self._startRunCallbacks(fail, 1) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 240, in _startRunCallbacks raise AlreadyCalledError() twisted.internet.defer.AlreadyCalledError: Traceback (most recent call last): File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 215, in errback self._startRunCallbacks(fail, 1) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 249, in _startRunCallbacks self._runCallbacks() File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 262, in _runCallbacks self.result = callback(self.result, *args, **kw) File "main.py", line 185, in _ebSessionRequest QMessageBox.critical(self, "Warder", "Can't connect to server.") --- <exception caught here> --- File "/usr/lib/python2.2/site-packages/twisted/internet/qtreactor.py", line 83, in read w.connectionLost(failure.Failure(why)) File "/usr/lib/python2.2/site-packages/twisted/internet/tcp.py", line 396, in connectionLost self.failIfNotConnected(error.ConnectError()) File "/usr/lib/python2.2/site-packages/twisted/internet/tcp.py", line 315, in failIfNotConnected self.connector.connectionFailed(failure.Failure(err)) File "/usr/lib/python2.2/site-packages/twisted/internet/base.py", line 527, in connectionFailed self.factory.clientConnectionFailed(self, reason) File "/usr/lib/python2.2/site-packages/twisted/web/xmlrpc.py", line 209, in clientConnectionLost self.deferred.errback(reason) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 215, in errback self._startRunCallbacks(fail, 1) File "/usr/lib/python2.2/site-packages/twisted/internet/defer.py", line 240, in _startRunCallbacks raise AlreadyCalledError() twisted.internet.defer.AlreadyCalledError: My question is: is it normal? How can I avoid such tracebacks? -- Egor Cheshkov <egor(a)iplus.ru>

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[Twisted-Python] WOVEN Question
by Philippe Lafoucrière 24 Jun '03

24 Jun '03

Hi all I have a question : I want to create a business platform using Woven. Like Zope (ZPT), I saw woven is separating logic/presentation (and control, yes, woven is based on MVC). But In zope, I can define some macros that could expand when I want. I mean, if I have a site like this +--------------------+ | Menu1 menu2 ----- | | | | | | some text | | | +--------------------+ and want an "include" of the menu in several pages. Should I use a new view ? It would be weird since I would have some large pieces of HTML in python code. Any suggestion ? -- Philippe Lafoucrière <lafou(a)wanadoo.fr> InFuzzion

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[Twisted-Python] Flow: better synchronous exceptions [patch]
by Christopher Armstrong 24 Jun '03

24 Jun '03

Here's a patch that changes semantics of Stage.next. Currently, if a Deferred errbacks with an exception that you haven't explicitly trapped, Stage.next will raise the Failure object (via the failure's trap method). I've changed this so it rather does `raise type(failure.value), failure.value, failure.tb'. What this means is that you can write code like this: d = flow.wrap(getDeferred()) yield d try: result = d.next() except ParticularError, e: traceback.print_exc() Two benefits here. One, I can actually say "except ParticularError" -- before, the type of the exception raised would be Failure. Two, the traceback printed by traceback.print_exc() will actually be useful and show you the stack trace of the original code that raised the error, rather than the traceback starting from the Failure.trap call. Of course, the traceback is cleaned once Deferred.runCallbacks finishes, but this only matters when the Deferred is resolved synchronously, as far as I can tell. In that case, you will get a pretty useless traceback, but it won't be any more useless than the tracebacks that used to be reported. The only drawback I see is that it breaks a flow test. :-) FailTest: exceptions.ZeroDivisionError raised instead of Failure Because the test is expecting a Failure to be raised, not the original, and more useful, exception. self.assertRaises(flow.Failure, list, flow.Block(badgen())) Clark, I'll be waiting for confirmation from you to commit this or trash it. -- Twisted | Christopher Armstrong: International Man of Twistery Radix | Release Manager, Twisted Project ---------+ http://twistedmatrix.com/users/radix.twistd/

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[Twisted-Python] Twisted and NT Services
by screwtape＠froup.com 24 Jun '03

24 Jun '03

At $FIRM, a good number of processes around the place are Python scripts using Twisted. Since they're functionally equivalent to Unix daemons, what's the best way of turning a Twisted script into a service? Also, I've gotten into the habit of using py2exe to turn scripts into standalone Win32 programs, and it would be really nice to be able to ship a standalone NT service. Unfortunately, there seems to be a "pick any two" relationship between Twisted, NT Services, and py2exe - when I try and combine all three, I get the following traceback inside my Application.run() call: File "twisted\internet\app.pyc", line 861, in run --- <exception caught here> --- File "twisted\python\log.pyc", line 64, in callWithLogger File "twisted\python\log.pyc", line 51, in callWithContext File "twisted\python\context.pyc", line 32, in callWithContext File "twisted\internet\default.pyc", line 122, in run File "twisted\internet\default.pyc", line 116, in startRunning File "twisted\internet\default.pyc", line 88, in _handleSignals exceptions.ValueError: signal only works in main thread If, in the Python source which contains the Service subclass, I put (at the top): from twisted.internet import win32eventreactor win32eventreactor.install() ...and then make it into a service, I get the same error (Entertainingly, if I put it *not* at the top, when I run the resulting exe I get the entertaining dialog box "Could not get Script info"). As you might have gathered, I'm not using .taps for these services - although I suspect they'd meet the 'don't reveal our source code to random people' requirement, I suspect they wouldn't help with the issue of installing Python and half a dozen extension modules on every server. Anyone have any hints or suggestions? -- ___________ ____________________________ | Screwtape | Reply-To: munged on Usenet |________ ______ ____ __ _ _ _ | | Nice sensible hobbits stay with Sméagol. |

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[Twisted-Python] flow again
by Pavel Pergamenshchik 24 Jun '03

24 Jun '03

The fix is trivial and it seems to give the expected behavior. Diff is at http://dunce.mine.nu:8080/flow.diff

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