Mailman 3 August 2002 - Twisted

[Twisted-Python] Patch for dbauth.tac in examples
by Steve Waterbury 06 Aug '02

06 Aug '02

Since I want to implement a PB-based app with db authorization, I was tinkering with the dbauth.tac example in an effort to educate myself. Changed "passport" to "cred" and set the database explicitly (created the dbcred tables in the "twisted" database that bugs uses). "Create an Identity", "remove", and "[change] password" work; there seems to be a problem with gotPerspectives' call to dbgadgets.py, but I haven't messed with gadgets (don't need them yet), so I won't be looking at that. (A gadgets cognoscente could fix it in seconds, anyway, I'm sure! ;^) Cheers, -- Steve. Stephen C. Waterbury http://misspiggy.gsfc.nasa.gov/people/waterbug.html *** dbauth.tac Tue Jul 30 10:25:04 2002 --- dbauth-new.tac Tue Jul 30 09:50:37 2002 *************** *** 1,18 **** #!python from twisted.internet.app import Application - from twisted.internet import passport from twisted.words import service, ircservice ! from twisted.enterprise import adbapi, dbpassport, dbgadgets from twisted.web import server ! auth = dbpassport.DatabaseAuthorizer(adbapi.ConnectionPool("pyPgSQL.PgSQL")) a = Application("db-auth", authorizer=auth) ws = service.Service("twisted.words", a) gdgt = dbgadgets.IdentitiesGadget(auth) ! a.listenOn(8486, server.Site(gdgt)) a.listenTCP(6667, ircservice.IRCGateway(ws)) --- 1,17 ---- #!python from twisted.internet.app import Application from twisted.words import service, ircservice ! from twisted.enterprise import adbapi, dbcred, dbgadgets from twisted.web import server ! auth = dbcred.DatabaseAuthorizer(adbapi.ConnectionPool("pyPgSQL.PgSQL", database="twisted")) a = Application("db-auth", authorizer=auth) ws = service.Service("twisted.words", a) gdgt = dbgadgets.IdentitiesGadget(auth) ! a.listenTCP(8486, server.Site(gdgt)) a.listenTCP(6667, ircservice.IRCGateway(ws))

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[Twisted-Python] ClientFactory.connectionLost(connector, reason)
by Tommi Virtanen 06 Aug '02

06 Aug '02

Hi. I've been groaning about how Twisted loses the actual errors, and does not allow programs to accurately report them to the user. Here is some progress on fixing that.. ClientFactory's connectionLost() method will get a new parameter "reason", which will be a failure.Failure(SomeException()). There will be no backwards compatibility; I will fix atleast the code in the main tree that has tests (that succeeded before the patch!). If you want to ensure compatibility, start using "def connectionLost(connector, reason=None)" right now. At a later stage, Protocol's connectionLost will get an extra argument also, a reason as above. There will be backwards compatibility, but having a non-reason-taking Protocol will be deprecated from that moment on, with a warning message. Now, what I need from you guys is 1) review the patch 2) write TCP/Connector/ClientFactory/Protocol tests about connectionLost (and ClientFactory.connectionFailed) 3) fix cReactor 4) fix win32eventreactor 5) fix kqreactor 6) test qtreactor 7) test gtkreactor My current working patch is attached. -- tv(a){{hq.yok.utu,havoc,gaeshido}.fi,{debian,wanderer}.org,stonesoft.com} double a,b=4,c;main(){for(;++a<2e6;c-=(b=-b)/a++);printf("%f\n",c);}

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[Twisted-Python] spread.sturdy reconnect delay
by Paul Boehm 04 Aug '02

04 Aug '02

currently, when spread.sturdy is unable to (re)connect (e.g. because the connection was refused/server not running), it retries at full speed.. without any delay.. implementing some kind of rate limiting is trivial, but i'm not sure about the right approach. the issue is current for me, as i'm using sturdy in my application and wouldn't want it to flood the network too much. i've come up with the following approaches: *) try n times, then wait i seconds, rinse, repeat *) try, sleep i, try, sleep i, ... *) try, sleep i++, try, sleep i++, .. suggestions?

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[Twisted-Python] debian/control bug: only python-twisted depends on python-gtk
by Tommi Virtanen 04 Aug '02

04 Aug '02

I think there's a bug in debian/control: currently, only python-twisted depends on python-gtk. But python-twisted is only a dummy package, and it's presence is not guaranteed in anyway (e.g. an app that needs python2.2 will depend on python2.2-twisted). Shouldn't python-gtk be split into python2.1-gtk, python2.2-gtk, and pythonX.Y-twisted depend on pythonX.Y-gtk? And while python-gtk is not split, python2.1-twisted should depend on python-gtk (>= 2.1), python-gtk (<< 2.2), and python2.2-twisted effectively has no gtk stuff. -- tv(a){{hq.yok.utu,havoc,gaeshido}.fi,{debian,wanderer}.org,stonesoft.com} double a,b=4,c;main(){for(;++a<2e6;c-=(b=-b)/a++);printf("%f\n",c);}

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[Twisted-Python] dbapi and pb question
by Fredrik 03 Aug '02

03 Aug '02

I am a newbie to this and i try to connect a database to pb, when trying this code i dont get any response from the server (running pbgtk.py)but the server outputs the print statement, how do I send bacdk a callback to the client ?? from twisted.enterprise import adbapi from twisted.spread import pb from twisted.internet import app class AgeDatabase(adbapi.Augmentation): """A simple example that can retrieve an age from the database""" def getAAge(self): sql = """SELECT age FROM person """ return self.runQuery(sql) def getAge(self, name): sql = """SELECT age FROM person where name = %s """ return self.runQuery(sql, name) class DefinedError(pb.Error): pass class SimplePerspective(pb.Perspective): db = AgeDatabase(adbapi.ConnectionPool("MySQLdb", db='test')) def perspective_echo(self, text): print 'echoing',text self.db.getAge(text).addCallback(self.gotAge,text) def perspective_error(self): raise DefinedError("exception!") ######################################### # the next function wont return to client def gotAge(self,resultlist, name): age = resultlist[0][0] # First field of first record print "%s is %d years old" % (name, age) return str(age) class SimpleService(pb.Service): def getPerspectiveNamed(self, name): p = SimplePerspective(name) p.setService(self) return p if __name__ == '__main__': import pbecho appl = app.Application("pbecho") pbecho.SimpleService("pbecho",appl).getPerspectiveNamed("guest").makeIdentity("guest") appl.listenTCP(pb.portno, pb.BrokerFactory(pb.AuthRoot(appl))) appl.run() #appl.save("start") Fredrik Bjornsson info(a)cleosan.com

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[Twisted-Python] Dynamic web application using twisted.web.resource
by Mukhsein Johari 03 Aug '02

03 Aug '02

Hello fellow twisters, This is a question (albeit a long one) directed at twisted.web and resource. The project: I would like to serve a dynamic website using the twisted web server. I understand that the webserver's 'root' directory can be set at a file? I may have a misunderstanding of the code and docs but if so, feel free to set me straight. The website (not real): http://www.mywebsite.com/ This is the root of the site, which is in reality a erm..rpy? program? Which means that there are _no_ static pages at all. And no other 'file' - everything goes through that .rpy file. (or whatever else I should be using) In a browser, entering this would get a dynamically 'constructed' page which is in fact: myobject.index() From here on, something like: http://www.mywebsite.com/projects/project_ako would actually be (in the code) something like: myobject.projects["project_ako"].index(myvar=None) which returns an html page suitable for the browser's consumption. On the other hand this: http://www.mywebsite.com/projects/project_ako?myvar=bold (for http GET. POST should be handled as well...how? I am guessing the request object?) Would call: myobject.projects["project_ako"].index(myvar='bold') Any other subobject of project_ako would 'call' a method on that object. So for: http://www.mywebsite.com/projects/project_ako/getSize Would call: myobject.projects["project_ako"].getSize() The return value being sent back to the browser. Calls to non-existing methods get a "No such method or object" error returned - formatted, of course. The question is of course, how do you differentiate between an object and a method? This is done by the application itself. It would check to see if that object has a method with that name, if not check to see if it has a child object with that name. Else return error. The thing is, I know I need to use twisted.web.resource but I'm not sure _how_. How does this fit in with the .rpy file? I think I need to create my modules and classes and then create an .rpy which acts as the erm..'interface' to the modules and classes. Could someone give me some hints and tips? Conceptually, it's quite simple but I can't seem to figure out how to do it with twisted...Anyway, thanks for any help, in advance. -- Regards, Mukhsein Johari

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[Twisted-Python] FilePager
by Paul Boehm 01 Aug '02

01 Aug '02

intended for twisted.spread.util: class FilePager(Pager): """A pager for files. """ def __init__(self, collector, file, chunkSize=8192): self.file = file self.chunkSize = chunkSize Pager.__init__(self, collector) def nextPage(self): data = self.file.read(self.chunkSize) if len(data) < self.chunkSize: self.stopPaging() return data

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[Twisted-Python] The stopConsuming method
by Matt Campbell 01 Aug '02

01 Aug '02

I noticed a method in twisted.internet.abstract.FileDescriptor called stopConsuming, which can be called by the producer to indicate that there is nothing more to produce. The method calls self.unregisterProducer, then self.loseConnection. I also noticed that this method isn't part of the IConsumer interface and isn't implemented by twisted.protocols.http.Request. I think this method should be added to IConsumer and implemented by all classes that implement that interface, because it enables the producer to indicate that there's nothing more to produce, whether the consumer be a Transport on which loseConnection is called to terminate the connection, or a Request on which finish is called to end that request/response process. -- Matt Campbell Email and MSN Messenger: mattcampbell(a)pobox.com Phone: (316) 652-8727 Web site: http://www.pobox.com/~mattcampbell/

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[Twisted-Python] WebConduit
by Donovan Preston 01 Aug '02

01 Aug '02

I developed this as a proof of concept and several people have expressed interest in seeing the implementation, so I thought I'd clean it up a little and send it to the list. The WebConduit is a project that I have been thinking about doing for several years now. Basically, it allows users to interact with a MUD server from a web page without any silly Java applets or frames that reload every 5 seconds. It does rely heavily on JavaScript to work, specifically it relies on the later browser's ability to have JavaScript affect the contents of the page after it has loaded. It also uses a trick pioneered by KnowNow, www.knownow.com, of opening a frame to a page on the server which the server never finishes sending to the browser. Using this technique, the Twisted server can push new JavaScript commands to this iframe in response to events on the remote server, and these JavaScript commands can in turn affect the DOM of the main page. It also uses another iframe to send commands to the twisted server. JavaScript can set the src attribute of the iframe and use GET parameters to send arbitrary variables to Twisted. Since all three iframes are coming from the same browser, the browser sends the same cookie with all three requests. Each request on the server then has access to the same Session object, and the three frames can communicate using this session object. That's about it, I'm pretty proud of the result. Enhoy. Donovan P.s. Put the rpy, js, and html files in a directory served by twisted.web, and put the py file on your PYTHONPATH somewhere.

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[Twisted-Python] Updated defer patch
by Christopher Armstrong 01 Aug '02

01 Aug '02

Ok, so I've added some code that wraps plain strings passed to .errback with a "DefaultException" and then issues a DeprecationWarning. Unfortunately, this patch causes tests to fail, since they pass a string to .errback and try to ensure that what gets passed to their error-callback is the same thing. So, following itamar's lead, this is backwards-compatibility-code-that's-only-half-backwards-compatible ;-) I've also updated the docstrings for callback and errback, they were out-of-date. (Note, this is an updated version of my last patch, so those modifications are duplicated here) Index: twisted/internet/defer.py =================================================================== RCS file: /cvs/Twisted/twisted/internet/defer.py,v retrieving revision 1.12 diff -u -r1.12 defer.py --- twisted/internet/defer.py 24 Jul 2002 19:04:56 -0000 1.12 +++ twisted/internet/defer.py 1 Aug 2002 01:36:17 -0000 @@ -32,6 +32,9 @@ class TimeoutError(Exception): pass +class DefaultException(Exception): + pass + def logError(err): log.err(err) return err @@ -103,7 +106,7 @@ These will be executed when the 'master' callback is run. """ cbs = ((callback, callbackArgs, callbackKeywords), - (errback or logError, errbackArgs, errbackKeywords)) + (errback or (lambda x: x), errbackArgs, errbackKeywords)) if self.default: self.callbacks[-1] = cbs else: @@ -152,10 +155,9 @@ Each callback will have its result passed as the first argument to the next; this way, the callbacks act as a - 'processing chain'. - - If this deferred has not been armed yet, nothing will happen until it - is armed. + 'processing chain'. Also, if the success-callback returns a Failure + or raises an Exception, processing will continue on the *error*- + callback chain. """ self._startRunCallbacks(result, 0) @@ -165,13 +167,24 @@ Each callback will have its result passed as the first argument to the next; this way, the callbacks act as a - 'processing chain'. - - If this deferred has not been armed yet, nothing will happen until it - is armed. - """ - if not fail: + 'processing chain'. Also, if the error-callback returns a non-Failure + or doesn't raise an Exception, processing will continue on the + *success*-callback chain. + + The argument must be a Failure instance or None, and strings are + accepted for backward-compatibility, but are deprecated. + """ + if isinstance(fail, types.StringType) or isinstance(fail, types.UnicodeType): + import warnings + warnings.warn( + "Don't pass strings (like %r) to Deferred.errback (replacing with a DefaultException)." % + fail, DeprecationWarning, stacklevel=2) + fail = failure.Failure(DefaultException(fail)) + elif fail is None: fail = failure.Failure() + elif not isinstance(fail, failure.Failure): + raise TypeError("Deferred.errback accepts failure.Failure instances, strings, or None. %r is none of these." % fail) + self._startRunCallbacks(fail, 1) @@ -228,14 +241,8 @@ callbackArgs=(0,), errbackArgs=(1,)) break - if type(self.result) != types.StringType: - # TODO: make this hack go away; it has something to do - # with PB returning strings from errbacks that are - # actually tracebacks that we still want to handle as - # errors sometimes... can't find exactly where right - # now - if not isinstance(self.result, failure.Failure): - self.isError = 0 + if not isinstance(self.result, failure.Failure): + self.isError = 0 except: self.result = failure.Failure() self.isError = 1 -- Chris Armstrong << radix(a)twistedmatrix.com >> http://twistedmatrix.com/users/carmstro.twistd/

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