Mailman 3 October 2011 - Twisted-web

Test
by Philippe Lafoucrière 05 Aug '21

05 Aug '21

Hi all just a test

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Porting the features of nevow.guard to twisted.web.guard
by L. Daniel Burr 05 Jan '12

05 Jan '12

Hi gang, Per a short chat with exarkun (thanks exarkun), I'm posting this to the list for discussion. A project upon which I am working requires a twisted.web service that allows a user to delegate authentication/authorization to a third party, e.g., Facebook, Twitter, et cetera. In so doing, I've found myself missing nevow.guard, since web.guard currently only has out-of-the-box support for HTTP Auth. I'd like to see web.guard expand to cover more kinds of auth, such as form-based auth or the OAuth-based solutions coming from so many social graph sites. With this in mind, I asked exarkun about this, and he mentioned that the only thing he does not consider to be garbage in nevow.guard is the feature-set, and that I should port the features to web, discarding the baggage. I'd like to solicit the list for some guidance as to what those features are, or should be, and hopefully end up with a ticket describing the features to be implemented, which I will then attempt to implement and contribute to twisted.web. Thanks, Daniel -- L. Daniel Burr ldanielburr(a)mac.com (312) 656-8387

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FTP: DTPFactory timeout - does an unhandled exception imply a problem?
by Tom Sheffler 31 Oct '11

31 Oct '11

I'm experimenting with the FTP protocol and noticed the following during certain timeout conditions. My first question is: when an unhandled exception occurs, do things get cleaned up properly, or is this an indication that we're losing memory or resources? Thanks. Here is an excerpt: 2011-10-31 10:14:04-0700 [-] timed out waiting for DTP connection 2011-10-31 10:14:04-0700 [-] Unexpected FTP error 2011-10-31 10:14:04-0700 [-] Unhandled Error Traceback (most recent call last): Failure: twisted.protocols.ftp.PortConnectionError: DTPFactory timeout 2011-10-31 10:14:14-0700 [ProtocolWrapper,0,127.0.0.1] cleanupDTP 2011-10-31 10:14:14-0700 [ProtocolWrapper,0,127.0.0.1] <<class 'twisted.internet.tcp.Port'> of twisted.protocols.ftp.DTPFactory on xxx> 2011-10-31 10:14:14-0700 [ProtocolWrapper,0,127.0.0.1] dtpFactory.stopFactory -Tom

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Using Twisted to process a pool of messages
by AmirBehzad Eslami 17 Oct '11

17 Oct '11

Dear List, e-Greetings, i'm a PHP developer, and I'm very new to the world of Python and Twisted. When it comes to use Twisted, my mind is unable to go beyond the Top-To-Down Code execution model of PHP... Help! i've been asked to write a service to process a list of SMS-messages, and send each person a response. The messages are located on a PostgreSQL database at a remote server. Inside an infitie loop in Python, I call a single URL every 5 seconds, which gives me an array of messages in JSON format. This URL has a special format, which a parameter, named "last_sms_id". URL: /give_me_messages.php?last_sms_id=XXX In the Python script, I set a value to this paramter to tell the Remote Script to only give me new messages, and ignore the old ones which I have already recieved. It means that I must update last_sms_id after processing each message. The URL finally returns an array of messages. i'm responsbile to process this array, and based on contents of each message, call a new URL, which doesn't matter for now. Now I'm asked to use Twisted to make my python script asynchronous. Well, I was PHP Programmer. I'm wondering how this application could become asynchronous. Let me explain. If the first call to the above URL fails to recieve content for some reason, what will happen? Does asynchronous mean that Python will invoke a new URL to the same URL again? or It will make a new URL call? How can I handle "last_sms_id" during these asynchronous calls? Thank you in advance, -behzad

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Ampoule vs PerspectiveBroker
by Jacek Furmankiewicz 15 Oct '11

15 Oct '11

Which is the recommended way for interprocess communication these days? Is it the existing PerspectiveBroker or Ampoule (which uses AMP as the underlying RPC protocol)? Are there drawbacks/benefits to either of them? Jacek

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Ampoule deferToAMPProcess confusion
by Jacek Furmankiewicz 15 Oct '11

15 Oct '11

Can someone point me to some good docs on Ampoule deferToAMPProcess? I am trying in vain to get the simplest possible example working, with no success. from ampoule import deferToAMPProcess, util from twisted.internet import reactor, defer def test(): return "TEST" @util.mainpoint def main(args): @defer.inlineCallbacks def _run(): val = yield deferToAMPProcess(test) print val reactor.stop() reactor.callLater(1, _run) reactor.run() Gives: exceptions.AttributeError: 'str' object has no attribute '_doCommand' I've tried different combinations, returnd Deferreds from the test() function, inline callbacks with defer.returnValue(). Can't get it to work. Looks like I am not the only one: https://answers.launchpad.net/ampoule/+question/75143 Thanks in advance Jacek

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Twisted web templates: do they support loops?
by Jacek Furmankiewicz 12 Oct '11

12 Oct '11

Looking at the (somewhat sparse) docs for twisted web templates: http://twistedmatrix.com/documents/current/web/howto/twisted-templates.html I see no mention of loops, like in Jinja2: {% for item in items %} <sometag>{{item.someproperty}}</sometag> {% endfor %} Is something like this supported? thx Jacek

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ssl verify callback called multiple times for each request
by Kevin McIntyre 05 Oct '11

05 Oct '11

Hello, I'm wondering why the verify callback is called multiple times for each request. I get 2 invalid callbacks and 1 valid callback. The 2 invalids are errnum 18, then 26...then a valid callback. I used https://help.ubuntu.com/community/OpenSSL for ca, and signed server and client certificates. -- Kevin McIntyre | Software Engineer | *Green Charge Networks* Cell 718-249-5058 | kmcintyre(a)greenchargenet.com | www.greenchargenet.com

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Hello introductions to me and one of my pet projects
by David J W 02 Oct '11

02 Oct '11

Hello, I've been using Twisted on and off now for about four years, mostly for personal projects and some R&D work for a few startups. I've been a semi-professional Python programmer for four years as well, unfortunately it only makes up about 15-20% of my annual income. That said for Python web development I was rather fond of Pylons and then moved from it to CherryPy. With those two frameworks influencing me, I wanted a similar interface for Twisted.Web and after a lot of trial and error I've got an alpha version proof of concept that is simply called txWeb. https://github.com/devdave/txWeb Very briefly using an example from JCalderone's wonderful collection of tutorial/examples: http://jcalderone.livejournal.com/49707.html Instead of doing from twisted.web.server import Site from twisted.web.resource import Resource from twisted.internet import reactor class FormPage(Resource): def render_GET(self, request) return '<html><body><form method="POST"><input name="the-field" type="text" /></form></body></html>' def render_POST(self, request): return '<html><body>You submitted: %s</body></html>' % (cgi.escape(request.args["the-field"][0]),) root = Resource() root.putChild("form", FormPage() ) factory = Site(root) reactor.listenTCP(8880, factory) reactor.run() the alternative would be: from txweb.core import Site #from twisted.web.resource import Resource from twisted.internet import reactor import cgi class Root(object): def form(self, request): return '<html><body><form action="/process" method="POST"><input name="the-field" type="text" /></form></body></html>' form.exposed = True index = form def process(self, request): return '<html><body>You submitted: %s</body></html>' % (cgi.escape(request.args["the-field"][0]),) process.exposed = True reactor.listenTCP(8880, Site(Root())) reactor.run() A cleaner version of the example above is available @ https://gist.github.com/1257921 My goals with txWeb isn't to replace the twisted.web Resource mechanism but instead provide an alternative that friendlier towards those with experience with Pylons/CherryPy/Django while avoiding duplicating anything that twisted.web provides ( ex. File resources can be class attributes ) That all said, any critique's or constructive input is very much welcome. So far I know the unit-tests need to be cleaned up, inside the routing routeRequest method the wrapper OneTimeResource is created, used, and thrown away which is somewhat wasteful as its a mostly stateless object. But I'm not sure if I'm missing something big that could make txWeb unviable for production use without some sort of major refactoring. Thanks, David W.

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CorePost 0.0.7 - all about content types
by Jacek Furmankiewicz 02 Oct '11

02 Oct '11

CorePost 0.0.7, the REST microframework built on top of twisted.web is out. http://pypi.python.org/pypi/CorePost/0.0.7 This is a big release with lots of enhancements all around content types: 1) automatic parsing of incoming content based on type @route("/post/json",(Http.POST,Http.PUT)) def test_json(self,request,**kwargs): return "%s" % json.dumps(request.json) @route("/post/xml",(Http.POST,Http.PUT)) def test_xml(self,request,**kwargs): return "%s" % ElementTree.tostring(request.xml) @route("/post/yaml",(Http.POST,Http.PUT)) def test_yaml(self,request,**kwargs): return "%s" % yaml.dump(request.yaml) 2) ability to route to different methods for the same URL by incoming content @route("/post/by/content",(Http.POST,Http.PUT),MediaType.APPLICATION_JSON) def test_content_app_json(self,request,**kwargs): return request.received_headers[HttpHeader.CONTENT_TYPE] @route("/post/by/content",(Http.POST,Http.PUT),(MediaType.TEXT_XML,MediaType.APPLICATION_XML)) def test_content_xml(self,request,**kwargs): return request.received_headers[HttpHeader.CONTENT_TYPE] @route("/post/by/content",(Http.POST,Http.PUT),MediaType.TEXT_YAML) def test_content_yaml(self,request,**kwargs): return request.received_headers[HttpHeader.CONTENT_TYPE] @route("/post/by/content",(Http.POST,Http.PUT)) def test_content_catch_all(self,request,**kwargs): return MediaType.WILDCARD 3) ability to return dict/list response and have them automatically convert to JSON or YAML, depending on what caller can Accept @route("/return/by/accept") def test_return_content_by_accepts(self,request,**kwargs): val = [{"test1":"Test1"},{"test2":"Test2"}] return val Calling this URL with "Accept: application/json" will return: [{"test1": "Test1"}, {"test2": "Test2"}] Calling it with "Accept: text/yaml" will return: - {test1: Test1} - {test2: Test2} 4) proper support for *defer.returnValue()* *in @defer.inlineCallbacks routers (which supports the auto-conversion shown above) @route("/",Http.GET) @defer.inlineCallbacks def root(self,request,**kwargs): val1 = yield db.query("SELECT ....") val2 = yield db.query("SELECT ....") defer.returnValue(val1 + val2) Cheers, Jacek

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