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
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
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?
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
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
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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
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
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
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
