Re: [Twisted-Python] "mind" introduced strangely in pb howto
Am 24.10.2013 um 09:02 schrieb Tobias Oberstein : >> I just tried to register so I could do that. When I clicked on the register >> button >> after filling out the username/password fields my browser (firefox) brought >> up a notice that the security certificate is invalid because of unavailable >> issuance chain information. Knowing absolutely nothing about internet >> security issues I thought I should mention this and ask if this is expected >> behavior. > > I wouldn't call that expected behavior, since > > a) the certificate used on twistedmatrix.com contains (as it should) > intermediate CA certs also (see attachments) I’m not sure what you mean with “contains”? It certainly *relies* on one but unfortunately doesn’t send it along (yet): $ openssl s_client -host www.twistedmatrix.com -port 443 CONNECTED(0003) depth=0 /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAddress=postmas...@twistedmatrix.com verify error:num=20:unable to get local issuer certificate verify return:1 depth=0 /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAddress=postmas...@twistedmatrix.com verify error:num=27:certificate not trusted verify return:1 depth=0 /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAddress=postmas...@twistedmatrix.com verify error:num=21:unable to verify the first certificate verify return:1 --- Certificate chain 0 s:/description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAddress=postmas...@twistedmatrix.com i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA --- signature.asc Description: Message signed with OpenPGP using GPGMail ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
Am 24.10.2013 um 08:08 schrieb Daniel Sank : > When I clicked on the > register button after filling out the username/password fields my > browser (firefox) brought up a notice that the security certificate is > invalid because of unavailable issuance chain information. Knowing > absolutely nothing about internet security issues I thought I should > mention this and ask if this is expected behavior. This will be fixed as soon as the now-in-prerelease Twisted 13.2 has been deployed to Twisted’s homepage (i.e. hopefully soon). Earlier versions don’t allow the specification of chain certificates unfortunately so it’s up to the browsers to fetch them – or not. signature.asc Description: Message signed with OpenPGP using GPGMail ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
Ah, right. Seems Chrome changed it's behavior .. at one point it wasn't able to load intermediate certs .. and hence I assumed from the dialog that Twisted cert has the intermediate cert contained. Wrong. FWIW, you can manually concatenate certs .. this is what we do (also for StartSSL): $ cat myserver_plain_cert.crt > myserver.crt $ cat ../sub.class1.server.sha2.ca.pem >> myserver.crt $ cat ../ca.pem >> myserver.crt A concatenated cert like above works today without the new code that is upcoming in Twisted. Which is cool also. However: this all does not explain (at least I dont understand) why the OP has that issue showing up .. Firefox is able to load intermediate CA certs from the net .. I have seen it .. also for StartSSL certs. Something is breaking this. Maybe it's MITM TLS, maybe they blocked intermediate cert auto-loading, .. dunno. /Tobias > -Ursprüngliche Nachricht- > Von: twisted-python-boun...@twistedmatrix.com [mailto:twisted-python- > boun...@twistedmatrix.com] Im Auftrag von Hynek Schlawack > Gesendet: Donnerstag, 24. Oktober 2013 09:16 > An: Twisted general discussion > Betreff: Re: [Twisted-Python] "mind" introduced strangely in pb howto > > Am 24.10.2013 um 09:02 schrieb Tobias Oberstein > : > > >> I just tried to register so I could do that. When I clicked on the > >> register button after filling out the username/password fields my > >> browser (firefox) brought up a notice that the security certificate > >> is invalid because of unavailable issuance chain information. Knowing > >> absolutely nothing about internet security issues I thought I should > >> mention this and ask if this is expected behavior. > > > > I wouldn't call that expected behavior, since > > > > a) the certificate used on twistedmatrix.com contains (as it should) > > intermediate CA certs also (see attachments) > > I'm not sure what you mean with "contains"? It certainly *relies* on one but > unfortunately doesn't send it along (yet): > > $ openssl s_client -host www.twistedmatrix.com -port 443 > CONNECTED(0003) > depth=0 > /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAd > dress=postmas...@twistedmatrix.com > verify error:num=20:unable to get local issuer certificate verify return:1 > depth=0 > /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAd > dress=postmas...@twistedmatrix.com > verify error:num=27:certificate not trusted verify return:1 > depth=0 > /description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/emailAd > dress=postmas...@twistedmatrix.com > verify error:num=21:unable to verify the first certificate verify return:1 > --- > Certificate chain > 0 > s:/description=S7lbCt7N2R4t9o8J/C=US/CN=www.twistedmatrix.com/email > Address=postmas...@twistedmatrix.com >i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate > Signing/CN=StartCom Class 1 Primary Intermediate Server CA > --- ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
Am 24.10.2013 um 09:48 schrieb Tobias Oberstein : > FWIW, you can manually concatenate certs .. this is what we do (also for > StartSSL): > >$ cat myserver_plain_cert.crt > myserver.crt >$ cat ../sub.class1.server.sha2.ca.pem >> myserver.crt >$ cat ../ca.pem >> myserver.crt > > A concatenated cert like above works today without the new code that is > upcoming in Twisted. Which is cool also. That is completely new to me. Are you sure you’re not mixing up Twisted’s behavior with nginx? If what you say is true, there would have never been the need for #2061 and the monkey patching everyone was doing before it landed. Can you point me at a server where you have deployed TLS like that please? signature.asc Description: Message signed with OpenPGP using GPGMail ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
> > A concatenated cert like above works today without the new code that is > upcoming in Twisted. Which is cool also. > > That is completely new to me. Are you sure you're not mixing up Twisted's > behavior with nginx? > > If what you say is true, there would have never been the need for #2061 and > the monkey patching everyone was doing before it landed. Can you point me > at a server where you have deployed TLS like that please? https://crossbardemo.tavendo.de/ws This works for me in Chrome, FF and IE. It is Twisted Web / Autobahn. Nothing in front. Now, using openssl s_client -host crossbardemo.tavendo.de -port 443 spits out errors complaining about "self-signed" cert inside. This might be because I not only included the StartSSL intermediate CA cert, but also their top-level CA cert (which is obviously self-signed). Maybe this is wrong, and one should only include up to (but excluding) root CA cert .. /Tobias ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] epoll keep sharing state between process even after fork.
> > On 03:46 pm, grindi...@gmail.com wrote: > >Hi everybody > > > >I a came across a surprising problem when using the epoll based > >reactor. > >(ticket here https://twistedmatrix.com/trac/ticket/6796) > > > >As you can see on the ticket, the epoll object seems to share some > >state > >even after fork. > > > >[snip] > > > >- Using spawnProcess as mentioned in the ticket comment, is not an > >option > >too, in my case, I need to share some state between the main process > >and > >subprocess. (I have on object in main process space that I want to > >inherit > >in all subprocess) > > This doesn't really explain why you can't use `spawnProcess`. There are > other ways to share state between processes. Perhaps if you describe > the object you have someone can suggest a way to share it that will > still satisfy your requirements without requiring that you use the > `multiprocessing` module. > > Jean-Paul > Hi. For the moment I share a factory object, but it's the underlying "protocol class" that is really needed. The code takes a factory object, and then launch a set of worker/process. when a connection is made on the parent process, the socket handler will be sent to one of the process (using sendmsg), the process will then run reactor.adoptStreamConnection and this is when we need the protocol class. There is an example of what I would like to achieve here https://github.com/Grindizer/scaletix the example works with select or poll reactor. with spawnProcess I guess the child process will need to somehow import the factory class and should be given the way to instanciate it ? isn't it ? I don't know other way to do it actually ? thankx again. ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] epoll keep sharing state between process even after fork.
> > 2. Arrange for the epoll object (or FD) to be closed after fork, but > > before exec, so that the child process can't fiddle with it > > See also: > > http://bugs.python.org/issue8713 > > ...which suggests Python 3.4 added fork+exec support to multiprocessing. > On Unix and older Python versions, you're stuck with plain fork and all > the attendant horribleness. > > This is a multiprocessing bug IMHO. > Hi again, I've found this discussion https://lkml.org/lkml/2007/10/27/25 the scenarios discussed are a bit different but it sounds to me related to the same problem. which makes me think this is not a python bug but may be an epoll design poblem with fork ! ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
Am 24.10.2013 um 11:10 schrieb Tobias Oberstein : >>> A concatenated cert like above works today without the new code that is >> upcoming in Twisted. Which is cool also. >> >> That is completely new to me. Are you sure you're not mixing up Twisted's >> behavior with nginx? >> >> If what you say is true, there would have never been the need for #2061 and >> the monkey patching everyone was doing before it landed. Can you point me >> at a server where you have deployed TLS like that please? > > https://crossbardemo.tavendo.de/ws > > This works for me in Chrome, FF and IE. It is Twisted Web / Autobahn. Nothing > in front. Your server definitely sends three certificates – that’s surprising/confusing. Could you double-check how you’ve achieved that? If you google for chain certs & Twisted you’ll find all kinds of monkey patches to achieve that; and when I run twistd -n web with a pem that has multiple certificates I still get sent only one from the server. I feel like I’m missing something. signature.asc Description: Message signed with OpenPGP using GPGMail ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
> Your server definitely sends three certificates - that's surprising/confusing. > > Could you double-check how you've achieved that? If you google for chain > certs & Twisted you'll find all kinds of monkey patches to achieve that; and > when I run twistd -n web with a pem that has multiple certificates I still get > sent only one from the server. I feel like I'm missing something. Ok, sorry, I forgot totally about it .. but this is what we do: https://github.com/crossbario/crossbar/blob/master/crossbar/crossbar/tlsctx.py#L73 It indeed relies on "use_certificate_chain_file". Sorry. My fault: it needs patching. /Tobias ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
Am 24.10.2013 um 12:44 schrieb Tobias Oberstein : >> Your server definitely sends three certificates - that's >> surprising/confusing. >> >> Could you double-check how you've achieved that? If you google for chain >> certs & Twisted you'll find all kinds of monkey patches to achieve that; and >> when I run twistd -n web with a pem that has multiple certificates I still >> get >> sent only one from the server. I feel like I'm missing something. > > Ok, sorry, I forgot totally about it .. but this is what we do: > > https://github.com/crossbario/crossbar/blob/master/crossbar/crossbar/tlsctx.py#L73 > > It indeed relies on "use_certificate_chain_file". > > Sorry. My fault: it needs patching. Phew, you really got me sweating there. :) Since you’re not using string representations there, you can move to CertificateOptions which has chain files sind 13.1 already (the string support slipped into 13.2 because I don’t know how to Python and it got reverted a few days before the release of 13.1 because of a Python 3 regression). signature.asc Description: Message signed with OpenPGP using GPGMail ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] epoll keep sharing state between process even after fork.
On 10/23/2013 12:50 PM, Phil Mayers wrote: This is a multiprocessing bug IMHO. This issue with multiprocessing appears in other places too. E.g. if you're using stdlib logging, child processes will try to rotate the parent process logs. Basically multiprocessing on Unix is utterly broken and should never be used (except in the fork+exec form in Python 3.4). -Itamar ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] epoll keep sharing state between process even after fork.
On 11:19 am, ita...@itamarst.org wrote: On 10/23/2013 12:50 PM, Phil Mayers wrote: This is a multiprocessing bug IMHO. This issue with multiprocessing appears in other places too. E.g. if you're using stdlib logging, child processes will try to rotate the parent process logs. Basically multiprocessing on Unix is utterly broken and should never be used (except in the fork+exec form in Python 3.4). To expand on that just a bit, the form of sharing that you get when you fork() but you don't exec() is very difficult to use correctly (I think it's an open question whether it's *possible* to use correctly in a Python program). The argument here is similar to the argument against shared-everything multithreading. While memory (and some other per-process state) is no longer shared after fork(), *some* per-process state is still shared. And all of the state that isn't shared is still a potential source of bugs since it's almost certainly the case that none of it cooperated with the fork() call - a call which happened at some arbitrary time and captured a snapshot of all the state in memory at an arbitrary point. Consider a simple implementation of a lock file, used to prevent multiple instances of a program from starting. There are several ways fork() could break such code. Perhaps it is partway through acquiring a lock on the lock file when the fork() occurs. Perhaps the result is that the file ends up locked but no process thinks it is holding the lock. Now no instances of the program are running. Or perhaps the lock is held when fork() happens and the problem only surfaces at unlock time. Perhaps one of the processes exits and releases the lock. Now the program is still running but the lock isn't held. And that's just one of the simplest possible examples of how things can go wrong. The nearly uncountable different ways for failures to creep in and the resulting impracticality (if not impossibility) of being able to test that Twisted (or any Python library) actually works when fork() is used means that it's not likely Twisted will ever be declared compatible with any fork()-without-exec() usage. You can find some examples of Twisted-using applications that run multiple processes, though. Apple CalendarServer does it by passing file descriptors to worker processes and sends them the location of a configuration file describing how they should behave. Divmod Mantissa does it by inserting self-describing work into a SQLite3 database. When the worker process finds one of these, it knows what code to load and run by looking at the fields in the row. These are variations on a theme - RPC, not shared (or duplicated) memory. Hope this helps, Jean-Paul ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
[Twisted-Python] WG: "mind" introduced strangely in pb howto
maybe the mailing list disallows >2 attachments .. again: http://picpaste.com/pics/step1-NB1LoEVR.1382620207.png http://picpaste.com/pics/step2-6zVhXeE6.1382620274.png http://picpaste.com/pics/step3-KTao4B2V.1382620308.png -Ursprüngliche Nachricht- Von: Tobias Oberstein Gesendet: Donnerstag, 24. Oktober 2013 14:35 An: Twisted general discussion Betreff: AW: [Twisted-Python] "mind" introduced strangely in pb howto Daniel, Ok, I've just tried using Firefox Portable (a self-contained browser not relying on any local installed stuff .. you can run that without Admin rights / installation - caution: when you are on some intranet, the former might be technically possible, but still disallowed .. and admins might still catch you): http://portableapps.com/apps/internet/firefox_portable See attached shots. This shows that the cert on twistedmatrix is somewhat lacking .. Firefox complains .. but I _do_ get HTTPS in the end. Are you surfing from a university (or some other) intranet? If so, the only reason I could think of is that the admins there have setup servers that _intercept_ the initial HTTPS negotiation. How to prove that? Well, that would now get quite technical .. not sure if you want to do that;) Or: just call them up;) If you are surfing from a regular residential dial-up or such: I have no clue why that happens to you .. /Tobias > -Ursprüngliche Nachricht- > Von: twisted-python-boun...@twistedmatrix.com [mailto:twisted-python- > boun...@twistedmatrix.com] Im Auftrag von Daniel Sank > Gesendet: Donnerstag, 24. Oktober 2013 09:35 > An: Twisted general discussion > Betreff: Re: [Twisted-Python] "mind" introduced strangely in pb howto > > > If you care, could you open the page in your browser, double click > > the small "lock icon" left to the "https://"; in the address bar and > > send a screenshot of the dialog shown (as the one attached)? > > Tried. Can't. Whenever I try to log in or out (bear with me) the lock > turns into a globe and I see firefox's security warning thingy. > Clicking on the globe shows the screens as given in attachments. > > Now you ask how can I be logging out if I never was able to log in? > After submitting the registration info I got the security warning so I > left that page and emailed the list. When I went back to > twistedmatrix.com to try again I was already logged in. Now when I > click the log out link I get the same security warning. Is it possible > that only the page resulting from log in/out has this problem? Again, > I know next to nothing about web security (unless it involved quantum > encryption in which case I'll talk your ears off). ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] epoll keep sharing state between process even after fork.
> > To expand on that just a bit, the form of sharing that you get when you > fork() but you don't exec() is very difficult to use correctly (I think > it's an open question whether it's *possible* to use correctly in a Python > program). > > The argument here is similar to the argument against shared-everything > multithreading. While memory (and some other per-process state) is no > longer shared after fork(), *some* per-process state is still shared. And > all of the state that isn't shared is still a potential source of bugs > since it's almost certainly the case that none of it cooperated with the > fork() call - a call which happened at some arbitrary time and captured a > snapshot of all the state in memory at an arbitrary point. > > Consider a simple implementation of a lock file, used to prevent multiple > instances of a program from starting. There are several ways fork() could > break such code. Perhaps it is partway through acquiring a lock on the > lock file when the fork() occurs. Perhaps the result is that the file ends > up locked but no process thinks it is holding the lock. Now no instances > of the program are running. Or perhaps the lock is held when fork() > happens and the problem only surfaces at unlock time. Perhaps one of the > processes exits and releases the lock. Now the program is still running > but the lock isn't held. > > And that's just one of the simplest possible examples of how things can go > wrong. > > The nearly uncountable different ways for failures to creep in and the > resulting impracticality (if not impossibility) of being able to test that > Twisted (or any Python library) actually works when fork() is used means > that it's not likely Twisted will ever be declared compatible with any > fork()-without-exec() usage. > > You can find some examples of Twisted-using applications that run multiple > processes, though. Apple CalendarServer does it by passing file > descriptors to worker processes and sends them the location of a > configuration file describing how they should behave. Divmod Mantissa does > it by inserting self-describing work into a SQLite3 database. When the > worker process finds one of these, it knows what code to load and run by > looking at the fields in the row. These are variations on a theme - RPC, > not shared (or duplicated) memory. > > Hope this helps, > Jean-Paul Thankx a lot. I'll probably rethink everything in my project hehe, but i'm glad I asked ! ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] "mind" introduced strangely in pb howto
On Oct 24, 2013, at 12:48 AM, Tobias Oberstein wrote: > However: this all does not explain (at least I dont understand) why the OP > has that issue showing up .. Firefox is able to load intermediate CA certs > from the net .. I have seen it .. also for StartSSL certs. Something is > breaking this. Maybe it's MITM TLS, maybe they blocked intermediate cert > auto-loading, .. dunno. Firefox does not load intermediate CA certs from the network. It - and pretty much all other browsers, as far as I know - will sometimes magically cache intermediary certificates. So if you visit the site in a browser that happens to have had the right intermediate CA certificate cached (probably because you visited another StartSSL free site, in twistedmatrix.com's case) then you will get no warning. This is why most people don't actually see a warning on the site :-). But we'll have this problem fixed For Real soon! -glyph ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] FTP without the protocol
On 10/23/13 7:30 PM, David Bolen wrote: Lloyd Carothers writes: For such a use case I'm surprised not to find an example. I think I just need a push in the right direction. Is producers/consumers the right approach? It's a bit dated at this point, but maybe this might spark some ideas: http://twistedmatrix.com/pipermail/twisted-python/2007-July/015738.html It's producer/consumer, which yes, is very efficient for streaming transfers. The code the post was based on is actually still in active use, but against an older twisted 2.5.0 installation, so I'm not sure how much tweaking it may need to adjust to the latest Twisted version. This looks pretty close to what I need and definitely a good starting point for me. I can make use of session specific information too, which will be nice. As you've been using it for a while, have you had any issues. Is it robust/stable? In practice this is paired with a separate set of code that implements a PB-based control channel over which the files to upload are negotiated. Would you be willing to share this as well? The binary transfer itself just has a small header in front of the data containing some authentication and size information, so it's derived from LineReceiver and switches to raw mode for the transfer. While I tend to prefer a separate control channel (though it certainly doesn't need to be PB based), you could also in-line the control information (so it becomes more like an HTTP transfer) if you wished. Gotcha. Maybe this is new since you wrote the above, but is FileSender the producer to use here? Perhaps its not fully developed but should there not also be a compliment FileReceiver to consume the file and write it out? BTW, passive FTP should be quite firewall friendly, unless you're talking about really locked down locations where the only thing allowed out is HTTP or something. But if you're not using passive mode yet, that might also be a quicker fix to your existing code base. Indeed, I use passive mode exclusively as clients often come from NATed nets. Generally FTP works ok but some organizations firewalls do strange things with that traffic, and even the good connections seem to have sporadic drops which often aren't handled well, at least with proftp. -- David ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
[Twisted-Python] Twisted 13.2.0pre1 Testing Feedback
Hi everyone, I've yet to hear back from anyone testing the prerelease - if you're able to, please do! Especially of interest to be tested would be the new HostnameEndpoint, which tries to connect to both the IPv4 and IPv6 addresses from a DNS lookup, and uses whichever is first - it makes Glyph excited for its inclusion, so it ought to make you ;) . It also supports SSL chain certificates, which should also fix up some issues using TLS with Twisted - this would also be great for people to test, and will hopefully remove a bunch of monkeypatching in everyone's code. Unless there are problems brought to our attention, it is unlikely that the 13.2.0pre will be different from the final release - so you can also use it to run against your application's test suites, so you know you're ready for upgrading to the full release later. :) The tarballs and NEWS file are available at http://twistedmatrix.com/Releases/pre/13.2.0pre1/ . The ticket for the 13.2 release is at https://twistedmatrix.com/trac/ticket/6795 - please comment on it if you have any issues! -hawkowl ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] Clean pb solution for two-way object sync?
> That will atomically combine the propagation of initial state with the > provision of the > back-propagation channel for updates to that state. My understanding of Cacheable is that it propagates initial state to the RemoteCache and then sends subsequent updates also to the RemoteCache. What I was originally asking about was how to allow the side holding the RemoteCache to request changes on the Cacheable. Your phrase "back-propagation" leads me to think that maybe this kind of thing is built into Cacheable, but I have not discovered how to use it. All of that said, in the end the answer to my original question seems to be "read this howto page:" http://twistedmatrix.com/documents/current/core/howto/pb-cred.html and then use the mind argument. Sincere thanks for your help, Daniel ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
