Mailman 3 December 2001 - Twisted

[Twisted-Python] What's so cool about Twisted?
by Michael Dartt Dec. 23, 2001

Dec. 23, 2001

(Yes, Glyph, I know it leads to increased sexual potency.) The really short version of this email: What features/tools/etc. does Twisted offer, how do they differ from conventional APIs/programs, and what do they do? (E.g. Sessions vs. cookies, Widgets, Passport....) What would its "feature list" look like? The longer version: The recent message about CGI/Sessions got me wondering how Twisted differs from other 'net frameworks, and how I can capitalize on its advantages. For example, I'm planning on running a blog on top of Twisted (all I need is a computer to code on...:P). On a standard web server, I'd probably set most of it up as CGIs, at least initially, and use cookies for dealing with "members" and such. But Twisted's got these things called Sessions and Passports, and I've seen a lot of bits thrown about in regard to Widgets. And there's probably a lot of stuff I haven't heard about. I know there's the "Why Twisted?" section, but it's *extremely* high-level, basically saying "It's written in Python, has a bunch of different protocols that can interface, and is well-supported," which is like someone handing you a tool box and telling you, "There are some really useful tools in here. They're like ones you may have heard about, but better." "So...why are they better? What do they do? Why would I want this tool set over a different one?" I realize at least part of this comes from my ignorance regarding network programming; I'm basically a neophyte when it comes to that. Otherwise, I could probably dive into the code and figure out what does what, and how it's different or better than the way things are normally done. As it is, I wouldn't know where to start. Once I know what the parts are and what they do, I should be able to use my m4D Py7h0n sKi11Z (;-}) to figure out the "how". Thanks in advance, Mike

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[Twisted-Python] Basic cookie support
by Itamar Shtull-Trauring Dec. 17, 2001

Dec. 17, 2001

Unless someone has a problem with it, this goes in tommorow. I'm willing to add a comment "don't use cookies, use sessions instead" ;) RCS file: /cvs/Twisted/twisted/web/server.py,v retrieving revision 1.31 diff -c -r1.31 server.py *** twisted/web/server.py 15 Dec 2001 03:24:10 -0000 1.31 --- twisted/web/server.py 17 Dec 2001 17:13:54 -0000 *************** *** 170,176 **** self.args = {} self.stack = [] self.headers = {} ! self.method, self.uri = command, path self.clientproto = version self.content = content --- 170,177 ---- self.args = {} self.stack = [] self.headers = {} ! self.cookies = [] ! self.method, self.uri = command, path self.clientproto = version self.content = content *************** *** 337,342 **** --- 338,345 ---- self.sendStatus(self.code, message) for name, value in self.headers.items(): self.sendHeader(name, value) + for cookie in self.cookies: + self.sendHeader("Set-Cookie", cookie) self.endHeaders() # if this is a "HEAD" request, we shouldn't return any data *************** *** 360,365 **** --- 363,391 ---- """ self.finish() + def addCookie(self, k, v, expires=None, domain=None, path=None, max_age=None, comment=None, secure=None): + """Set an outgoing HTTP cookie. + """ + cookie = '%s="%s"' % (k, v) + if not (expires is None): + cookie = cookie +"; Expires=%s" % expires + if not (domain is None): + cookie = cookie +"; Domain=%s" % domain + if not (path is None): + cookie = cookie +"; Path=%s" % path + if not (max_age is None): + cookie = cookie +"; Max-Age=%s" % max_age + if not (comment is None): + cookie = cookie +"; Comment=%s" % comment + if not (secure is None) and secure: + cookie = cookie +"; Secure" + self.cookies.append(cookie) + + def view_addCookie(self, k, v, **kwargs): + """Remote version of addCookie; same interface. + """ + apply(self.addCookie, (k, v), kwargs) + def setHeader(self, k, v): """Set an outgoing HTTP header. """ *************** *** 418,425 **** # if it still hasn't been set, fix it up. if not self.session: self.session = self.site.makeSession() ! self.setHeader('Set-Cookie', ! '%s=%s' % (cookiename, self.session.uid)) self.session.touch() return self.session --- 444,450 ---- # if it still hasn't been set, fix it up. if not self.session: self.session = self.site.makeSession() ! self.addCookie(cookiename, self.session.uid) self.session.touch() return self.session

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[Twisted-Python] Test, Please Ignore
by Glyph Lefkowitz Dec. 17, 2001

Dec. 17, 2001

This is a test to make sure that Mailman is still working after Zaibach's upgrade to Debian Unstable. Hey, why are you reading this? I said it was a test. Ignore it! Oh well, too late. -- ______ you are in a maze of twisted little applications, all | |_\ remarkably consistent. | | -- glyph lefkowitz, glyph @ twisted matrix . com |_____| http://www.twistedmatrix.com/

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[Twisted-Python] What's everyone using Twisted for?
by Glyph Lefkowitz Dec. 14, 2001

Dec. 14, 2001

So, occasionally I've heard from people using Twisted. I haven't made an index of them yet, or even the domains it's being used in. If you subscribe to this list, please send in something detailing your usage of Twisted, what you like about it, what you don't like about it, and if you like, feel free to tack on something outrageous for the ad copy :-). If you don't want to be quoted or your project is not ready for public consumption, email me personally. Especially, I'd like to know about what modules you're using for your application and what your experience has been with them. (Even if you've mentioned your app before, please post about it again. If you're not using the latest, let me know which version you deployed at.) -- ______ you are in a maze of twisted little applications, all | |_\ remarkably consistent. | | -- glyph lefkowitz, glyph @ twisted matrix . com |_____| http://www.twistedmatrix.com/

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[Twisted-Python] new stuff in twisted
by Sean Riley Dec. 13, 2001

Dec. 13, 2001

Hi all, i've been working with glyph on some new stuff lately in the twisted world. here is a brief description of some of it: twisted.enterprise the addition of the "Augmentation" class to the adbapi give a convenient place to put database interface code. dbpassport adds database authentication of users. there are a standard set of tables for identities and perspectives, hooks for dynamic creation of perspectives from the database, and a web interface to manager it all. plans exist to add service specific database tables and user data. this piece feels pretty solid to me and is the infrastructure used for the two below pieces. twisted.metrics this is a system for monitoring distributed servers running twisted applications. it has a central database of metrics data and a real-time data cache in the metrics manager server. there is a web interface to the manager which allows real-time viewing of the status of the servers in the network. it is intended for real-time load balancing between servers and storing metrics history information for data-mining. it accepts both operating system statistics (through an OsMetrics Collector) and application specific statistics which are both correlated into the same database schema. this system is still in development, but is already functional. now that the db support is solid, it should progress quickly. twisted.forum a web based message board / posting system with a database backend. this is currently in an alpha stage. it needs work to hook up the user authentication piece, but it already has functioning forums, messages and threads. all of these systems use web widgets extensively. i have to say that web widgets are easy to use and provide a huge amount of functionality. ---- "If it's not running programs or fusing atoms, it's just bending space." Sean Riley sean(a)ninjaneering.com

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[Twisted-Python] Running a twisted server as a WinNT service
by Andrew Bennetts Dec. 12, 2001

Dec. 12, 2001

This is just a quick mail to let people know what I had to do to make a Twisted server work as a WinNT service. First, it should be noted that I'm not using twistd or tap files, partly because this server has no state that needs persisting, and also because I'm not sure how to use them ;) Basically, the service is really really simple: --- import win32serviceutil, win32service import MyServer from twisted.python.log import startLogging import twisted.internet.main class MyTwistedService(win32serviceutil.ServiceFramework): def SvcDoRun(): # Can't use stdout for logging -- .flush will barf startLogging(open('c:/mylogfile.log','a')) MyServer.main() def SvcStop(): self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING) twisted.internet.main.shutDown() if __name__ == '__main__': win32serviceutil.HandleCommandLine(MyTwistedService) --- And that does it. The trickiest bit is that you need to set the log file to something other than stdout, otherwise it dies due to a Bad File Descriptor error doing logfile.flush(). Other than that, it is basically boilerplate code (if you're familiar with Win32 services written in Python). I wonder if there is a more integrated way to do this, though? -Andrew.

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[Twisted-Python] OSI 7 layer network model
by Sean Riley Dec. 12, 2001

Dec. 12, 2001

I was wondering... how would you categorize the various pieces of Twisted in the OSI 7 Layer Network Model? The layers are: 1. Physical - hardware 2. Data Link - ethernet 3. Network - IP 4. Transport - protocols(TCP/IP, UDP) 5. Session 6. Presentation 7. Application I'm not sure how "session" fits in with Twisted. Maybe Perspectives play the role of sessions? Presentation is defined as "where application data is packed/unpacked" - which seems to include both banana and jelly? I'd like to be able to draw a diagram showing where python fits into this model and where the opportunities for optimization are found. By explicitly showing that the implentations of these layers are actually in C or provided by the OS, the perception that "python is slow" could be mitigated somewhat. I think that keeping the "session" layer in python can be justified with the added security of no buffer overflows, and the requirement for integration with the python application layer. There also are few tight loops in this layer. The "Presentation" layer seems to be the most computationally expensive software layer as it includes encryptions, packing and compression. It is here that the pure python implentation is a little scary for most people - and so it is here where the most education and explicit categorization of components by implementation would be most useful. ---- "If it's not running programs or fusing atoms, it's just bending space." Sean Riley sean(a)ninjaneering.com

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[Twisted-Python] FW: [Python-Dev] ExtensionClass plans (was Re: [ZODB-Dev] Another ExtensionClass incompatibility: __pow__())
by Jason L. Asbahr Dec. 10, 2001

Dec. 10, 2001

This might be of interest... Jason -----Original Message----- From: python-dev-admin(a)python.org [mailto:python-dev-admin@python.org]On Behalf Of Jim Fulton Sent: Saturday, December 01, 2001 11:23 AM To: Greg Ward Cc: zodb-dev(a)zope.org; Python-dev(a)python.org Subject: [Python-Dev] ExtensionClass plans (was Re: [ZODB-Dev] Another ExtensionClass incompatibility: __pow__()) Greg Ward wrote: > > Sigh. In addition to ignoring __r{add,sub,mul,div}__() methods, > ExtensionClass also calls __pow__() differently. (snip) > So what is the future of ExtensionClass, anyways? I intend that Python 2.2 (or maybe 2.3) will make it irrelevent. > Are the little > incompatibility bugs between classic Python classes and ExtensionClass > ever going to be fixed? Probably not by us. Patches are gratefully accepted. We are going to keep supporting it for a while at it's current level to support projects other than ZODB that require it. > Or has ExtensionClass been abandoned in favour > of a future ZODB based on new-style Python 2.2 classes? This is my plan. :) > If so, when > will this future ZODB become reality? I'm glad you asked. As part of our Zope 3 prototyping, we've begun moving toward a next generation of ZODB. We currently have an experimental ZODB that: - Doesn't require ExtensionClass - Does depend on new-style Python classes - Separates the Persistence and Transaction frameworks - Uses weak references in the cache - Uses a pure-python Persistent implementation (hence no BTrees). We will be creaing a C Persistent base class. All the fun is currently happening on the Zope-3x-branch branch of the Zope3 checkout. You can see the relevent ZODB pieces at: http://cvs.zope.org/Zope3/lib/python/Persistence/?only_with_tag=Zope-3x-bran ch http://cvs.zope.org/Zope3/lib/python/Transaction/?only_with_tag=Zope-3x-bran ch http://cvs.zope.org/Zope3/lib/python/ZODB/?only_with_tag=Zope-3x-branch Of course all of this is highly speculative at this point. Stay tuned. ;) Jim -- Jim Fulton mailto:jim@zope.com Python Powered! CTO (888) 344-4332 http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org _______________________________________________ Python-Dev mailing list Python-Dev(a)python.org http://mail.python.org/mailman/listinfo/python-dev

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[Twisted-Python] FW: [Python-Dev] FYI: MIT's dynamic language design panel now online
by Jason L. Asbahr Dec. 10, 2001

Dec. 10, 2001

Another item of interest to the Twisted community (particularly Glyph and Dash). Jason (Yes I'm cleaning out my mailboxes...and sending the BEST TO YOU! ;-) -----Original Message----- From: python-dev-admin(a)python.org [mailto:python-dev-admin@python.org]On Behalf Of Fredrik Lundh Sent: Tuesday, May 15, 2001 1:21 PM To: python-dev(a)python.org Subject: [Python-Dev] FYI: MIT's dynamic language design panel now online in case anyone has two hours to spare, and the right software, MIT's dynamic languages group has posted a quicktime video of their recent panel on language design. http://www.ai.mit.edu/projects/dynlangs/wizards-panels.html (what 1/2 should result in, why it's good to have both CPython and JPython, why whitespace is significant, why language design is perhaps more related to architecture than math, and lots of other goodies from Guy Steele and others) Cheers /F _______________________________________________ Python-Dev mailing list Python-Dev(a)python.org http://mail.python.org/mailman/listinfo/python-dev

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RE: [Twisted-Python] python's "import" is giving me a headache.
by j.her＠t-online.de Dec. 6, 2001

Dec. 6, 2001

On 05 Dec 2001 15:30:51 -0500, Chris Armstrong wrote: >(well, you can, but you can't prevent all modules in a package from >being imported). Yes, you can, like... __init__: from tw.import import _delayedImport oldname = _delayedImport('newname') or even sys.modules[__name__] = _delayedImporter(__name__, lookup_dict_with_old_names) Nothing in this is pretty in any way. Ciao, Jürgen

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