Mailman 3 May 2004 - Twisted-web

Test
by Philippe Lafoucrière 05 Aug '21

05 Aug '21

Hi all just a test

3 2

Multiple choices
by vicky 09 Jul '04

09 Jul '04

Hi, I'm working on forms with nevow. I would like to know if it's possible to use multiple choices with ChoiceRenderer. I noticed that the multiple choices are not available because the class ProcessTyped return data[0] and not the complete list data. I know that I could create my own classes and functions but I wanted to know if it was already possible to do it. Thank you Vicky

4 4

IRedirectAfterPost
by vicky 28 May '04

28 May '04

Hi, I'm having some problems with iformless.IRedirectAfterPost. The first time I post my form, I see my results' page with the data posted. But when I use "back" on my browser and I try to post my form again, the IRedirectAfterPost doesn't seem to be done. It bring me back the page with the form posted (no data in my fields). Only once out of two my form is posted correctly even if I'm using the back button. I didn't find out how to fix it. Vicky

2 2

ResourceTemplate is cool
by Craig H. Anderson 27 May '04

27 May '04

Greetings, While sitting and waiting for our Cold Fusion consultant to show up I remembered that I had twisted loaded on my XP box. So I looked over the documentation and found the page 'Light Weight Templating With Resource Templates' I downloaded and installed Quixote and in 2 hours time have a little demo of what we plan to do with Cold Fusion. Being a Python devotee, I can see I'll have a lot of fun with this. Are there any examples using ResoureTemplate beyond the QuoteResource() page?

1 0

IRedirectAfterPost
by vicky 27 May '04

27 May '04

Hi, I finally found where the probleme is. It's in the file Rend.py and in the locateChild function of the class FreeformChildMixin. The problem is the content of context. To solve my problem, it was necessary to put request.context automatically in context instead of verifying if the context is empty. Otherwise the IRedirectAfterPost works once out of two. I would like to know if this change can cause many other problems and if it is possible for you to change it directly in the code so when I'll update nevow the change will be in it. Here's the class with the modification I made: class FreeformChildMixin: """Mixin that handles locateChild for freeform segments.""" def locateChild(self, request, segments): ## The method or property name we are going to validate ainst/affect bindingName = None name = segments[0] if name.startswith('freeform_post!'): configurableName, bindingName = name.split('!')[1:3] elif name.startswith('freeform-action-post!'): configurableName, request.args['freeform-actee'] = name.split('!')[1:3] bindingName = request.args['freeform-action'][0] if bindingName: #this is where I made my change #Instead of verifying if the ctx is empty, I automatically put #request.context in ctx ctx = request.context self.context = ctx ctx.remember(self, inevow.IResource) ctx.remember(request, inevow.IRequest) cf = iformless.IConfigurableFactory(self) c = cf.locateConfigurable(ctx, configurableName) return self.webFormPost(request, self, c, ctx, bindingName, request.args) return NotFound Thanks, Vicky

2 1

FW: [Twisted-Python] How to organize a web application?
by Alexander May 26 May '04

26 May '04

Hello all, I am looking for advice on how to organize a web application. I've never written a web application before, and would appreciate any insight into best practices and overall structure. I have html pages, html templates, an underlying database, and (hopefully) an understanding of twisted and nevow. What is the best way to glue all of this together? For example, what is the best way to associate derived rend.Page classes with html templates? I'll have all these different data and render functions that could potentially be used by many different templates. Do I create one monster rend.Page derived class responsible for servicing all the possible display an render functions? That seems wrong. What's the alternative? What is the best way to manage links? The html page template will link to each other, mostly at the discretion of the html designers (admittedly me at first). Should I utilize the underlying file system to define the link structure as I might do for static html site? If yes, should I use static.File and create a special resource type for the html template and then return rend.Page derived classes? Or should I do something else all together? What is the best way to manage state (non database)? Cookies or mugged URLS mapped to closures seems like it would work well. Perhaps someone has some experience doing this? I took a look at the Quotient source, and did not see any html templates at all, so I assume all the html generation is occurring dynamically via Stan or some other method. Likewise for nevow Calendar example which has a single html template and links to dynamically generated pages (I'll probably need to do that too). Thought and comments? Thanks, Alex _______________________________________________ Twisted-Python mailing list Twisted-Python(a)twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python

1 0

Nevow newbie question
by Pedro Lima 21 May '04

21 May '04

Hello all, I would like to use nevow with data from a sql query, but I'm having trouble figuring out how to do it. >From what I understood, data is fetched in the data_xxx methods. But if I use the ConnectionPool query I get a Defered as a result. And the data_xxx method should return the data and not a Defered, correct? The other way would be to get a db connection and make the query in the data_xxx method. But then, I suppose it would not run in a thread and it would block the processing. Can someone give me a hint on how to do it? Thanks Pedro Lima

2 1

New cache proposal
by Valentino Volonghi 20 May '04

20 May '04

I've seen taht at least in ten.py and in loaders.py you cache adapters and templates. Not too long ago I've written a metaclass that would cache instances based on what arguments were passed during instantiation. http://mattgoodall.dyndns.org:8081/105 cache = {} class MyMetaTemplate(type): def __call__(self, *args): cached = cache.get(args, None) print cache, cached if not cached: instance = type.__call__(self, *args) cache.update({args:instance}) return instance return cached class Pippo(object): __metaclass__ = MyMetaTemplate template = '' def __init__(self, arg1, arg2, arg3): self.template = arg1 a = Pippo(1,2,3) b = Pippo(2,3,4) c = Pippo(1,2,3) d = Pippo(2,3,4) e = Pippo(5,6,7) f = Pippo(5,6,7) print id(a), id(b), id(c), id(d), id(e), id(f) I think the only 'drawback' is that it needs new-style classes, but It would be easier to use since you don't need extra checking in methods but once you instantiate you know that the object you are working on is a new one (if it wasn't cached) or the cached one. HTH

1 0

new http
by James Y Knight 19 May '04

19 May '04

Firstly: HTTP 1.1 compliance is not easy. It's not *too* bad for an origin server, but if Twisted wants a compliant HTTP proxy module (even non-caching), there's a lot of requirements. Squid made a nice table of the 473 MUST/MAY/SHOULD [NOT]s which is helpful. Anyhow as it's nearing workability, I thought I'd just write a bit about how I it's structured. This is kinda rambling but oh well. ;) There's 4 main classes on the path for handling a HTTP connection: HTTPFactory: a ServerFactory that creates HTTPChannel objects for each incoming TCP connection. HTTPChannel: keeps track of queued 'ChannelRequest' objects, and some of the splitting up of the incoming data into distinct requests work. ChannelRequest: handles all the low-level hop-by-hop behavior. Request: high level request/response behavior. The split off of ChannelRequest from bits of HTTPChannel and bits of Request is geared towards allowing a different request transport than normal HTTP. PB is one possibility. Also, it simplifies the Request object and gives it a cleaner API that only has to deal with the actual request, not the details of transfer encodings, pipelined connections, etc. ChannelRequest provides the following methods for Requests to call: def writeIntermediateResponse(self, code, headers=None, code_message=None): def writeHeaders(self, code, headers, code_message=None): def writeData(self, data): def finish(self): def abortConnection(self): Also the producer methods: def registerProducer(self, producer, streaming): def unregisterProducer(self): Request provides the following callbacks that are called by ChannelRequest: def __init__(self, chanRequest, command, path, version, in_headers): def handleContentChunk(self, data): def handleContentComplete(self): def connectionLost(self, reason): The core of the public interface to this whole thing are the fields/methods on Request: method: HTTP method used uri: URI passed in the request. clientproto: Tuple like (1,1) out_headers: a Headers object containing the headers to output. in_headers: a Headers object containing the incoming headers. acceptData(self): Call to notify the sender that you intend to accept the request. checkPreconditions(self); check if the preconditions are satisfied, and thus whether the action should take place/the output data should be written. write(self, data): Call to write some data. If headers haven't been written yet, write them. writeFile(...): Call to write a file in an optimized way like sendfile(). TBD what actually goes here. finish(self): Call when you've finished writing data. Callbacks to override: process(self): called from __init__. Incoming headers have been received, but no data yet. Should do resource lookup. handleContentChunk(self, data): A chunk of data was received. handleContentComplete(self): The incoming data is done. connectionLost(self): the underlying connection was lost. in_headers/out_headers are objects of type http_headers.Headers which provides for a standardized way of translating between raw string headers and structured data headers. Some of the header parsers are not written yet. Unlike the old Request, this one is going to do nothing with incoming data. No form processing, no buffering, no nothing. No args processing of the uri, either. The "full featured" subclass of Request (e.g. server.Request) can do that stuff. It is expected to do all URI frobbing and then a locateChild() lookup at process() time (before the data has arrived). Then, figure out what the located resource wants to do with the incoming data (ignore it, buffer it all up into one string, or pass it along as it comes in). Note that this means locateChild can't use POST arguments. Then, in the usual case, render() would be called after all the data has arrived and form processing has been done on it. But for some resources, e.g. a proxying resource, it would just send all the data straight through, without doing form processing. James

1 0

can't load modules in nevow tutorial
by jbdunsmo＠utmb.edu 19 May '04

19 May '04

i just installed nevow and am trying to run the tutorial (http://nevow.com/Nevow2004Tutorial.html), but i get the following error that the modules located in the Example4 directory can't be found: # twistd -noy sched.tac 2004/05/19 08:08 CDT [-] Log opened. 2004/05/19 08:08 CDT [-] twistd 1.2.0 (/usr/bin/python 2.3.3) starting up 2004/05/19 08:08 CDT [-] reactor class: twisted.internet.default.SelectReactor 2004/05/19 08:08 CDT [-] Loading sched.tac... 2004/05/19 08:08 CDT [-] Traceback (most recent call last): 2004/05/19 08:08 CDT [-] File "/usr/lib/python2.3/site-packages/twisted/application/app.py", line 117, in getApplication 2004/05/19 08:08 CDT [-] application = service.loadApplication(filename, style, passphrase) 2004/05/19 08:08 CDT [-] File "/usr/lib/python2.3/site-packages/twisted/application/service.py", line 291, in loadApplication 2004/05/19 08:08 CDT [-] application = sob.loadValueFromFile(filename, 'application', passphrase) 2004/05/19 08:08 CDT [-] File "/usr/lib/python2.3/site-packages/twisted/persisted/sob.py", line 213, in loadValueFromFile 2004/05/19 08:08 CDT [-] exec data in d, d 2004/05/19 08:08 CDT [-] File "<string>", line 3, in ? 2004/05/19 08:08 CDT [-] ImportError: No module named iCal 2004/05/19 08:08 CDT [-] Failed to load application: No module named iCal 2004/05/19 08:08 CDT [-] Traceback (most recent call last): File "/usr/bin/twistd", line 36, in ? run() File "/usr/lib/python2.3/site-packages/twisted/scripts/twistd.py", line 188, in run app.run(runApp, ServerOptions) File "/usr/lib/python2.3/site-packages/twisted/application/app.py", line 204, in run runApp(config) File "/usr/lib/python2.3/site-packages/twisted/scripts/twistd.py", line 178, in runApp application = app.getApplication(config, passphrase) --- <exception caught here> --- File "/usr/lib/python2.3/site-packages/twisted/application/app.py", line 117, in getApplication application = service.loadApplication(filename, style, passphrase) File "/usr/lib/python2.3/site-packages/twisted/application/service.py", line 291, in loadApplication application = sob.loadValueFromFile(filename, 'application', passphrase) File "/usr/lib/python2.3/site-packages/twisted/persisted/sob.py", line 213, in loadValueFromFile exec data in d, d File "<string>", line 3, in ? exceptions.ImportError: No module named iCal Failed to load application: No module named iCal 2004/05/19 08:08 CDT [-] when i set $PYTHONPATH to /usr/share/doc/nevow-0.1/doc/Example4 it works fine. what's the problem here? thanks, jason

2 1

Twisted-web May 2004