Re: [Twisted-Python] order of remote requests
Wolfgang Rohdewald wrote: Hi, when I send two remote calls A and B over the network, in that order, using the twisted perspective broker callRemote method, is it granted that A is processed first on the other side even if B arrives first? Or should I only send B after I got an answer to A? It depends on the server, and what exactly you want to happen. Perspective broker can have many concurrent remote calls on the same connection, and depending on how the server is implemented it might process those sequentially in the order they arrive, or concurrently, or even in an arbitrary order. So if call A really must be completed before starting B, then the client must not make call B until it knows A has finished. -Andrew. ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] order of remote requests
On Tuesday 29 December 2009, Andrew Bennetts wrote: Wolfgang Rohdewald wrote: when I send two remote calls A and B over the network, in that order, using the twisted perspective broker callRemote method, is it granted that A is processed first on the other side even if B arrives first? Or should I only send B after I got an answer to A? It depends on the server, and what exactly you want to happen. Perspective broker can have many concurrent remote calls on the same connection, and depending on how the server is implemented it might process those sequentially in the order they arrive, or concurrently, or even in an arbitrary order. So if call A really must be completed before starting B, then the client must not make call B until it knows A has finished. I should have given more details, sorry. I am writing both the server and the client with twisted pb. The server (a game server) sends messages to four player clients. Say the game server sends messages A and B to a player client. Is it granted that the player client always processes A first even if the internet routes the messages differently and B arrives first? -- Wolfgang ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] order of remote requests
On 2009.12.29 12:53:07 +0100, Wolfgang Rohdewald wrote: On Tuesday 29 December 2009, Andrew Bennetts wrote: Wolfgang Rohdewald wrote: when I send two remote calls A and B over the network, in that order, using the twisted perspective broker callRemote method, is it granted that A is processed first on the other side even if B arrives first? Or should I only send B after I got an answer to A? It depends on the server, and what exactly you want to happen. Perspective broker can have many concurrent remote calls on the same connection, and depending on how the server is implemented it might process those sequentially in the order they arrive, or concurrently, or even in an arbitrary order. So if call A really must be completed before starting B, then the client must not make call B until it knows A has finished. I should have given more details, sorry. I am writing both the server and the client with twisted pb. The server (a game server) sends messages to four player clients. Say the game server sends messages A and B to a player client. Is it granted that the player client always processes A first even if the internet routes the messages differently and B arrives first? TCP guarantees in-order message delivery. If you send A before B over the same TCP connection, and A and B reach the client, then the client will receive A before B. Each Twisted process is single-threaded by default. So if you use TCP, and keep the message processing code simple, then I think you'll get messages processed in the order you expect. I've never noticed a problem with out-of-order messages in my PB game, anyway. -- David Riptondrip...@ripton.net ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] order of remote requests
On Tuesday 29 December 2009, David Ripton wrote: TCP guarantees in-order message delivery. If you send A before B over the same TCP connection, and A and B reach the client, then the client will receive A before B. Of course - now I wonder what made me think otherwise. Thank you for your explanation! -- Wolfgang ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] order of remote requests
Wolfgang Rohdewald wrote: [...] I should have given more details, sorry. I am writing both the server and the client with twisted pb. The server (a game server) sends messages to four player clients. Say the game server sends messages A and B to a player client. Is it granted that the player client always processes A first even if the internet routes the messages differently and B arrives first? A PB connection uses a single TCP connection. TCP guarantees that the bytes will arrive in order (or not at all), so the messages will arrive at the client in the order the server sent them, assuming there is one persistent PB connection between each client and the server (which seems likely from your description). So it is impossible for the internet to route the messages such that B will arrive before A. Neither PB nor TCP guarantee anything about when the recipient “processes” those messages though, just that they will arrive in the order they were sent. For example consider if A and B arrive very close together (in the same millisecond, say) and the client processes them by dispatching to a thread pool, which might take 10s or even 100s of milliseconds to fully process the message (and determine a reply, if applicable)... then depending on the exact work required and exactly how the OS schedules the threads, then B might be fully processed before A is, even though A arrived first. Apologies for such a pedantically precise and abstract answer, but what exactly you mean when you say “processes” is a bit ambiguous. I hope this reply helps. -Andrew. ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] twisted version of openid
On Dec 29, 2009, at 1:31 PM, Kevin Horn wrote: On Tue, Dec 29, 2009 at 10:12 AM, Raj kumar k_r_a_j_ku...@yahoo.co.in wrote: Hi, Currently I'm having a server running under twisted. I'm planning to implement openid in my application. Is there any twisted version of openid api? I need some reference to go through openid examples. Thanks in advance. Raj. Google is you friend: https://launchpad.net/txopenid It may not suit your purposes exactly, but it seems like a good place to start. txopenid is an identity provider for OpenID version 1.1. That is, it can provide credentials for sites that accept OpenID logins, based on data stored in a MySQL database. It won't currently help you *accept* OpenID as an authentication mechanism, but it's a great provider, IMNSHO ;-) I use it as my identity provider, and so far it works well for my purposes. It also has been pleasantly stable the whole time I've been running it (at least as monitored by Nagios). Also, it provides a number of utility functions that are essential to the OpenID spec which should make writing a consumer a bit easier (particularly in regards to hmac digest support and encoding integers into their big-endian two's complement as a binary string...ugh)... Admittedly OpenID is at version 2.x these days, so I'm hoping soon to update the provider and/or write a consumer implementation. I'd like to think OpenID is finally starting to catch on... -phil___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
