Mailman 3 November 2005 - Twisted-web

Dynamical generated slots
by Johann Siegele 25 Nov '05

25 Nov '05

Hello, im looking for a possibility to generate Slots for a livepage dynamical. my code for the livepage looks like this, it works fine, but i can not update any of the slots! def render_mytable(self, ctx, data): mydetail=[] for i in range(1,15): mydetail.append([T.td [T.slot('test'+str(i), "default")]]) if i % 3 is 0: mydetail.append([T.tr[T.td['-test-']]],) return ctx.tag[mydetail] template: <table nevow:render="mytable" name="mytabletest"/> it should be possible that the user can change the text in the row n and colume x. this do not work: client.set('test1', text) i think the problem is, that the slots are not hardcoded. is there a other possibility. thank you very much!

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resource constructor called on every request
by Remi Cool 24 Nov '05

24 Nov '05

Hello, I don't know if this is a 'normal' twisted/nevow operation procedure, but my base resources' __init__ is called on every request. Since a putChild for XMLRPC is setup in this __init__ (which includes a lot of code), I'm worried about execess overhead. Is there a way to include the XMLRPC section in a way that it get's initialized only once? I need the XMLRPC functionality on the same port as the HTTP(S) for firewall reasons. Something else ... in locateChild -> if segments[0] == '': # If the server is looking for the root page segments will be ('',) # then renderHTTP will be called on self When I return self, () a max recursion error is the result ... what should I return here? -- CODE -- class httpResource(rend.Page): addSlash = True def __init__(self, service): rend.Page.__init__(self) self.service = service self.putChild('RPC2', protocols.xmlrpc(self.service)) rt = static.File("www") rt.ignoreExt(".rpy") rt.processors = {'.rpy': script.ResourceScript, '.php': phpScript} rt.indexNames.append('index.php') self.putChild('www', rt) def locateChild(self, ctx, segments): """""" if segments[0] == '': # If the server is looking for the root page segments will be ('',) # then renderHTTP will be called on self return None, () elif segments[0] in ctx.tag.children.keys(): return ctx.tag.children[segments[0]], segments[1:] else: return None, () def renderHTTP(self, ctx): """""" if self == ctx: return "<html><body>renderHTTP: ROOT</body></html>" return ctx.tag components.registerAdapter(httpResource, IowwService, inevow.IResource)

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How to use twistd on Windows to run a simple webserver
by Keith.Gunderson＠act.org 22 Nov '05

22 Nov '05

I've finally found a good reason to delve into twisted at my job. I've been keeping up with your progress over the past few years, but now I can't seem to get the simplest of webapps to run. (I've read all the docs and blogs that I can get my eyes on.) The basics....No IRC during business hours, Win2000, python2.4, latest TwistedSumo plus TwistedWeb2 reinstalled for good measure. I want to run the 'Simple application' described the twisted.web2 introduction. (pasted below.) Twistd.py has syslog issues for me. My 'twistdWithSyslogRemoved.py' does nothing but release an inaudible chirp. (As does _twistd.py .) What additional hints can you give me? I have delusions of nevow, mantissa, and glory in my future. But one step at a time. Many, many thanks. (from intro.txt) from twisted.web2 import server, http, resource class Toplevel(resource.Resource): addSlash = True def render(self, ctx): return http.Response(stream="Hello monkey!") site = server.Site(Toplevel()) # Standard twisted application Boilerplate from twisted.application import service, strports application = service.Application("demoserver") s = strports.service('tcp:8080', http.HTTPFactory(site)) s.setServiceParent(application) Save this program as ``example1.py``, and then run it via ``twistd -ny example1.py``. ``twistd`` is the Twisted runner; it knows how to execute applications by looking for the magic ``application`` variable declared at top-level. You can also run your server daemonized, via ``twistd -oy example1.py``. You can then access your server via the url "http://localhost:8080/". For more deployment options, see the deployment_ chapter. Keith Gunderson Performance Test Analyst IT Audit and Reporting ACT, Inc. 301 ACT Drive Iowa City, IA 52245 (319) 337-1548 Voice (319) 337-1766 Fax

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Re: [Twisted-web] How to use twistd on Windows to run a simple webserver
by Keith.Gunderson＠act.org 22 Nov '05

22 Nov '05

Thats the ticket. Very nice. The shortcut was hidden in a menu under a button labeled Start :( Here's the details... C:\WINNT\system32\CMD.EXE /k C:\SOMEWHERE\python24\lib\site-packages\twiste d\twistenv.bat C:\SOMEWHERE\python24\scripts Keith Gunderson Jean-Paul Calderone <exarkun(a)divmod.com> To: twisted-web(a)twistedmatrix.com Sent by: cc: twisted-web-bounces@twiste Subject: Re: [Twisted-web] How to use twistd on Windows to run a simple webserver dmatrix.com 11/22/2005 02:03 PM Please respond to "Discussion of twisted.web, Nevow, and Woven" On Tue, 22 Nov 2005 13:52:17 -0600, keith.gunderson(a)act.org wrote: >I've finally found a good reason to delve into twisted at my job. I've >been keeping up with your progress over the past few years, but now I can't >seem to get the simplest of webapps to run. (I've read all the docs and >blogs that I can get my eyes on.) ... twisted/scripts/twistd.py is a private implementation module, it is not intended to be invoked directly. It is only used when you use twistd on POSIX. twisted/scripts/_twistw.py is also a private implementation module. It is only used when you use twistd on Windows. bin/twistd is the executable program intended to be invoked. I'm not sure how the latest Windows installer works. It used to provide a command shell (cmd.exe with the environment configured to make working with Twisted easier) from which you could run "twistd" without specifying the full location. This may still be the case. In any case, you definitely don't want to run anything in twisted/scripts/ manually. Jean-Paul _______________________________________________ Twisted-web mailing list Twisted-web(a)twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web

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Twisted Network Programming Essentials
by Stephen Nightingale 22 Nov '05

22 Nov '05

Fine Book. I'm working through the examples. Hit a problem with the wordcountproxy.py example, under the explanation of HTTP Proxy Servers, on page 62.. As this __might__ be an issue with Twisted itself, I'm cross-posting here as well as back to O'Reilly errata. The issue is that the: 'reactor.listenTCP(WEB_PORT, WebReportFactory(counter))' call precipitates an error message in _getfullpathname in Lib/ntpath.py, called from web/http.py, and the error is: 'TypeError: coercing to Unicode: need string or buffer, WordCounter found' The full traceback is given below. N.B. I'm using Python 2.4.1 on Win XP. I wonder if anyone else has come across this issue? Any insights gratefully received, Regards, Stephen Nightingale. 2005/11/21 23:20 GMT Standard Time [-] Log opened. 2005/11/21 23:20 GMT Standard Time [-] __main__.WordCountProxyFactory starting on 8001 2005/11/21 23:20 GMT Standard Time [-] Starting factory <__main__.WordCountProxyFactory instance at 0x00F03878> 2005/11/21 23:20 GMT Standard Time [-] Traceback (most recent call last): 2005/11/21 23:20 GMT Standard Time [-] File "wordcountproxy.py", line 137, in ? 2005/11/21 23:20 GMT Standard Time [-] reactor.listenTCP(WEB_PORT, WebReportFactory(counter)) 2005/11/21 23:20 GMT Standard Time [-] File "D:\Python\Lib\site-packages\twisted\web\http.py", line 1086, in __init__ 2005/11/21 23:20 GMT Standard Time [-] logPath = os.path.abspath(logPath) 2005/11/21 23:20 GMT Standard Time [-] File "d:\Python\lib\ntpath.py", line 500, in abspath 2005/11/21 23:20 GMT Standard Time [-] path = _getfullpathname(path) 2005/11/21 23:20 GMT Standard Time [-] TypeError: coercing to Unicode: need string or buffer, WordCounter found --------------------------------- To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre.

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LivePage cannot append rows to tables?
by Mike Pelletier 22 Nov '05

22 Nov '05

I'm at my wit's end! Have mercy on a clueless JS user and examine the attached page. The problem it illustates is one I am having with livepage.js's nevow_appendNode function. I am finding that whenever I attempt to append a row to a table (or to a tbody, or for that matter to anything else) the HTML is silently stripped out and my node is added as a single #TEXT node. However, appending a DIV works fine, even when technically illegal; a DIV node containing the #TEXT is added. The attachment includes a copy'n'pasted version of nevow_appendNode. The only modification I have made to it is to add an alert() which demonstrates the precise point of failure; assigning "what" to "newspan.innerHTML". Note that the <div> tags are unmolested, but the <tr> and <td> tags are stripped. I get the same behaviour from FF and IE, while Konq just barfs with a DOM exception 7. I simply don't know how to chase this one down any further. I hope someone will tell me I'm a moron and point out what I've done wrong, but I think the solution is going to require a change to nevow_appendNode. Thanks muchly, Mike.

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State and web2 (or, how to not follow REST)
by Clark C. Evans 21 Nov '05

21 Nov '05

This is an attempt to summarize a conversation I had /w glyph on #twisted.web earlier today. I've attached the IRC log. The basic problem discussed was how to manage server-side state; which in particular includes sessions and authentication. Stateful servers cause serious problems with scalability and with bug hunting. Glyph is adamant that getSession() as it currently works (by raising a redirect exception if the session does not already exist) must be fixed. I absolutely agree with this; as it currently stands the top-level resource must always ask for a Session object to avoid unexpected redirects down the request stream. This shouldn't be a lesson of experience; it should be built-in convention. A related issue, one to which Glyph is very concerned about, is the implicit coupling of resources during the handling of a given request. In particular, where a resource X (located at /foo) sets a variable V in the request R and then a resource Y (at /foo/bar) comes to depend upon this variable V. If this coupling is not made explicit and checked-for, then an opportunity for rather obscure bugs emerge; one where the resource Y is re-used in another context (say at /bing/bar) and still assumes that V is set. While Twisted framework cannot prevent such nonsense, it should propose an alternative mechanism, or at the very least not promote such dynamic resource dependencies. One way to make resource dependencies explicit is to require that the constructor for a child resource take an optional ancestor resource in its constructor. In this model, each user/session would in essence have its own top-level resource, and all resources which dependended upon session state would take in its constructor the parent resource. This approach has a few deficiencies: (a) there might be more than one instance of a resource Y at /foo/bar, one for each user; this is not only inefficient but makes debugging hard beause the relation of a URI onto a resource object is not a relation; (b) while leaf resources, such as a static.File object need not take a parent resource in its constructor; it forces generic Resources to have a "pass-through" parent Resource, even if it does not need state information. In the IRC conversation, I believe (and hope) this was proposed and then eventually rejected; but I'm not sure. I don't like the idea of any Resource objects in the system being user or session specific. Another alternative is to add a getSiteResource() and setSiteResource() to the Request interface. The SiteResource would then contain the top level resource "/" which reflected the user's Session and any other application specific server side state (ie, nasty persistent global-like variables which breaks REST). The SiteResource would therefore be an appliation specific object; it could, for example contain an session-id and a username property for down-stream Resource authorization. Later in the IRC chat, Glyph said he is "coming around to the fact that it's not really a resource". This is good; beacuse I don't think that this server side state is a resource by the definition of web architecture. I didn't mention it in the IRC chat, but I'm now thinking that these methods on the request object could be setState() and getState(); and that they return an arbitrary application-defined object which has all of the nastly (but unfortunately mandatory and pratical) session and request "global variables" that break REST and can cause all sorts of problems. Glyph mentioned earlier in an email that perhaps a declarative syntax could be introduced so that arbitrary Resources could advertise exactly what "state" they will access; and hence, these sorts of errors could be detected and reported more intelligently. I like this idea; it is framework support to prompt developers to put in the assertion checks that they should already be doing. It codifies a solid pratice, and this is a good thing. ;) I think that Glyph and I did have a clear agreement: all of the information on the State (in Glyph's terms SiteResource) object should be set (and perhaps made read-only?) _before_ any Resource delegation is made. We do have a slight (but very slight) semantic difference. I see the process of setting up a session and creating any server-side state as done in a IRequestHandler _before_ any IResources are called. Glyph sees this as being done "by a resource which sits at the the top level". In both models, this sort of stuff is done before your average every-day resources are processed; my model is just more explicit and allows for chaining IRequestHandlers (such as one for sessions, and another one for authentiction) before IResources are processed. I think that's about it. I just want a simple solution to this, and soon. Best, Clark

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Forms - question
by Maciej Kucharz 20 Nov '05

20 Nov '05

Hello, I have a question for users of "forms" (http://forms- project.pollenation.net). I'm looking for a way to do something like this: class UserAdd(forms.ResourceMixin, rend.Page): def __init__(self, user, step=1, *a, **k): apply(forms.ResourceMixin.__init__, (self, user) + a, k) self.user = user self.step = step def form_edit(self, ctx): [...] form.addAction(submit) return form def formSubmitted(self ,ctx, form, data): print form, data return UserAdd('myuser', self.step) I want to render form, depend on "self.step" (i want have a few form steps on my site). In contruction like above on action submit i have neverending loop. thanks, for any advice PS. I simply want to have an effect like in "testformless.py" (from nevow examples): """ class NameWizard(rend.Page): docFactory = loaders.stan(tags.html[tags.h1["What is your name"], webform.renderForms()]) def bind_name(self, ctx): return [('name', annotate.String())] def name(self, name): return QuestWizard(name) class QuestWizard(rend.Page): docFactory = loaders.stan(tags.html[tags.h1["What is your quest"], webform.renderForms()]) def bind_quest(self, ctx): return [('quest', annotate.Choice(['Find the Grail', 'Get laid', 'Earn twenty bucks', 'Destroy the sun']))] def quest(self, quest): return FinalWizard((self.original, quest)) """ -- qk

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TEST - ignore it!
by Maciej Kucharz 20 Nov '05

20 Nov '05

Test. -- qk

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HTTP-AUTH for web2 / Kudos on web2's operation
by Clark C. Evans 20 Nov '05

20 Nov '05

Hello. I didn't see any examples of how to do HTTP Digest authentication with twisted.web2, so I updated my ancient code in the sandbox -- it was easier than I expected. Nice job with web2. http://cvs.twistedmatrix.com/cvs/sandbox/cce/digest2.py I had a few observations with my first run /w web2: 1. It would be delightful if WebContext had a request() helper method that did the appropriate adaptation to an IRequest 2. It would be excellent if locateChild was deferrable, often times you need to access a database to construct dynamically the appropriate resource. This is not a syncronous operation. 3. It would be wonderful if HTTPError took arguments that would construct an appropriate Response... it is trivial, but a nice touch if it did. Overall, web2 is looking quite nice; I'll have more feedback once my entire application is ported. Cheers, Clark

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