in reply to Re: share socket connections amongst multiple threads?
in thread share socket connections amongst multiple threads?
Am I missing what you are trying to do here?
I believe so. Each thread is a spawned socket connection between the server and client that is connecting. When each threaded socket gets sent data on it's respective connection it needs to re-broadcast this data to all the other socket connections. I am not trying to share simple text or integer data between the threads, I am trying to make each socket connection aware of the rest.
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Re^3: share socket connections amongst multiple threads?
by BrowserUk (Patriarch) on Jul 08, 2005 at 20:17 UTC | |
Your explanation of what you are trying to do is still lacking. Just for a moment, lets assume that you can arrange for multiple threads to have a copy of the same socket. At this point, you have 1 client writing to 1 socket and multiple server threads wanting to read from it. The first thread that reads the socket will get the data, and all the others won't. You mention "re-broadcasting". How? Sockets are point to point. In order for any one server thread to be able to re-broadcast data to every other server thread, it would need to have a separate socket connection for each of those other servers and re-transmit the data to all of them. For 2 server threads, you would need 2 sockets. 1 to the client and 1 between the threads. For 3 server threads, you would need 3 sockets + the client: s1<->s2; s1<->s3; s2<->s3; + s(n)<->C; For 4 server threads, you would need 6 sockets + the client: s1<->s2; s1<->s3; s1<->s4; s2<->s3; s2<->s4; s3<->s4; For 5 server threads, you would need 10 sockets + the client: ... For 6 server threads, you would need 15 ... I think you can see where this is going. And, remember we are just assuming that you could successfully share the socket to the client between multiple threads, which you cannot. You would also have to arrange for each thread to "monitor" all of these sockets waiting for input. Put succinctly, what you are trying to do is not a "limitation of threads", but a limitation of your understanding. A bad design that could never work. In order for us to suggest solutions, you will need to explain what you are trying to achieve, rather than how you are trying to achieve it. If the idea is that all threads will have access to data read from a client, then reading that data from the socket on one thread only and then placing it into shared memory such that all clients have access to it is possible--but there is a problem. | [reply] |
by Elijah (Hermit) on Jul 09, 2005 at 04:30 UTC | |
Does this give you a better idea of what I am talking about now? | [reply] |
by BrowserUk (Patriarch) on Jul 09, 2005 at 05:04 UTC | |
When the server accept()'s a connection I add the connection id to a hash ... What do you mean by "connection id"? My assumption is that you mean an IO::Socket::INET handle. This is a blessed ref:
which, for very good reason, you cannot put into a shared hash. Basically, the methods that are attached to a blessed object like IO::Socket::INET=GLOB(0x1a05ec0) are tied to the thread in which the object handle (a GLOB in this case) is instantiated. So, if you share that object with another thread and that other thread attempts to call a method upon it, it will try to invoke code from the other thread. That cannot work, which is why Perl stops you from trying to do that. There are two approached to solving this problem that I am aware of: This is easier to arrange by having a "controller" thread that also has a queue and each client forwards a copy of data it receives to the contoller via it's queue and it forwards it to each of the other clients. Again, this works best if a central controller thread is given access to handles from each of the client handles and it reblesses them. The clients would then forward their messages to the controller and it would forward them (directly) to the clients via the reblessed handles. This still leaves the problem of conveying those handles from the clients to the controller. Not insurmountable, but requires some jiggery pokery. All in all, the queues method is probably easier. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.
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Re^3: share socket connections amongst multiple threads?
by waswas-fng (Curate) on Jul 08, 2005 at 19:48 UTC | |
-Waswas | [reply] |