1st thing: sorry about the double-post. i don't know why that happened. If this one gets double posted too, i apologize in advance.
2nd: php.net/pcntl On Tuesday 21 May 2002 23:30 pm, Miguel Cruz wrote: > I don't think you're going to get Apache to hand you the socket. > > However, you can write a program using the standalone (CGI) PHP > interpreter that will act like a server - check out > http://php.net/socket_create_listen for more info. > > You could redirect from your standard web server to your listening PHP app > running on another port. You'll then have to implement at least a subset > of the HTTP protocol in order to get browsers to talk to you. > > Unfortunately, since you can't - to the best of my knowledge - fork a PHP > program, you're going to have to do your own homebrew threading which will > make life slightly complicated. > > miguel > > On 22 May 2002, Vinod Panicker wrote: > > It still seems like I havent made the problem clear enough. > > > > I am aware of the print(), echo() and flush() functions and what > > they do. It does not fit in as a solution. Let me explain my > > problem more elaborately - > > The client calls a PHP script, script_a.php on the Apache web > > server, using a Keep-Alive connection. The script returns some > > response to the client which it uses. Now since the connection is > > a Keep-alive, apache still has it open for reading and writing. > > When the client wants to call other scripts, it just sends the > > request over the same connection. Now the thing is that if the > > server needs to send some ASYNCHRONOUS data to the client, without > > the client requesting for anything, a normal PHP script wont be > > able to do it, since the script would get executed by the web > > server ONLY on a client request (coz thats the way HTTP works). > > Now what i was thinking was - if i could get hold of the socket > > that is being used by apache to send data to the client, I could > > effectively write() to it, from a C++ app or a PHP script (which > > gets invoked from lets say another server). print(), echo() etc > > are functions that write to the output stream, which is opened as > > a result of the clients request, by the web server. > > > > I want the ability to write to a socket thats been created earlier > > - i want to steal it from Apache, so that i can use it when and > > where i like. > > > > Functions like echo() and print() are not going to work here, i > > will have to use write() so that i can specify the socket to which > > the data has to be written! > > > > Hope the problem is understood now. > > > > Now for your question - > > When the client wants to send data to the server, it just has to > > open a socket connection with the web server, and issue a GET or a > > POST request! if the connection is a keep-alive connection, and > > it has already been created, the client just has to do a GET or a > > POST without the need to connect(). > > > > This mechanism, where the client frequently connects() to the > > server and checks for messages is called polling. One way of > > reducing the high overhead of this is to reuse the connection by > > using a keep-alive connection. A still better improvement would > > be to remove the need for a poll altogether, by doing something > > (thats what my question is all about) on the server so that it can > > send data asynchronously to the server. > > > > > > Tx, > > Vinod. > > > > On Wed, 22 May 2002 Bogdan Stancescu wrote : > > >For your specific problem, I think Mr. Lemos has provided a > > >viable solution (using print() or echo() and flush() whenever you > > >need to, instead of grabbing the socket and write() to it). My > > >problem however is how you envision solving the communication the > > >other way around (i.e. when the CLIENT wants to send data to the > > >server). > > > > > >Bogdan > > > > > >Vinod Panicker wrote: > > >>Hi, > > >> > > >>Tx for your very prompt reply. > > >> > > >>Yeah, I'll post the solution as soon as I find it someplace. > > >> > > >>Let me outline the problem in more detail - > > >> > > >>Client (VC++) calls a PHP script on the server, specifies the > > >>connection type as Keep-Alive. The PHP script, somehow (still a > > >>big question) gets the socket on which the apache server has > > >>received the client request (so that it can send data to the > > >>client later) and stores it in a database. > > >> > > >>Now whenever another PHP script wants to send data > > >>asynchronously to the client, it gets the socket from the > > >>database, and just calls a write() on it. Since the connection > > >>is still open (Keep-Alive), the client receives the information, > > >>and doesnt have to poll the server periodically. > > >> > > >>The application of this is indeed destined for a messaging > > >>product, and could benefit a lot of other areas as well. > > >> > > >>The only thing that is needed is the socket from apache. > > >> > > >>Someone somewhere knows how to get this done, i'm sure :) > > >> > > >>Possibly a hack into the PHP module can get this done, i'm open > > >>to suggestions. > > >> > > >>Tx, > > >>Vinod. > > >> > > >>On Tue, 21 May 2002 Bogdan Stancescu wrote : > > >>>Hi! > > >>> > > >>>I'm looking for an answer to your questions as well, so if you > > >>>do find a solution on other lists, could you please post it > > >>>here as well? > > >>> > > >>>Regarding the issue, your proposal wouldn't make for > > >>>full-duplex as far as I understand since I don't see how the > > >>>client would be able to send any data on the same connection > > >>>_after_ getting connected. > > >>> > > >>>What are you using on the other end of the pipe (on the > > >>>client)? Plain HTML? Flash? Java? Something else? > > >>> > > >>>Bogdan > > >>> > > >>>Vinod Panicker wrote: > > >>>>Hi, > > >>>> > > >>>>We have developed a client-server application where the server > > >>>>needs to send asynchronous data to the client. Now since we > > >>>>are using Apache/PHP/MySQL, the client needs to poll the > > >>>>server periodically for information. > > >>>> > > >>>>I was thinking if there was some way to get around this basic > > >>>>problem. I understand that this is how things are supposed to > > >>>>work, but it would be just great if i could PUSH data from the > > >>>>server to the client, using HTTP. > > >>>> > > >>>>Since HTTP is a request/response based protocol, Apache would > > >>>>not send any data to the client asynchronously. So what i was > > >>>>thinking was - If i tell the server to allow Keep-Alive > > >>>>connections, and increase the timeout value and max requests, > > >>>>I would effectively have a constant TCP connection. Now the > > >>>>only problem would be of sending asynchronous data to the > > >>>>client. Solution? Here goes - If there was some way in which > > >>>>i could get hold of the file descriptor(socket) that is being > > >>>>used by apache to write data to the client, then i could, from > > >>>>a PHP script also send any data to the client using the socket > > >>>>functions of PHP since i already have the socket with me. > > >>>> > > >>>>This would mean that the client doesnt have to poll the server > > >>>>for data any more... and if the connection does get closed, > > >>>>the client could reconnect to the server asking for another > > >>>>keep-alive connection. > > >>>> > > >>>>Now I know that this is probably the wrong place to put such a > > >>>>query - maybe the apache list would have been better. But > > >>>>since I'm using PHP out here, i thought i'd give it a try. > > >>>> > > >>>>Does the solution sound very outlandish? Are there any > > >>>>pitfalls? And finally, how do i get hold of the socket? > > > > > >-- PHP General Mailing List (http://www.php.net/) > > >To unsubscribe, visit: http://www.php.net/unsub.php > > > > _________________________________________________________ > > Click below to visit monsterindia.com and review jobs in India or > > Abroad > > http://monsterindia.rediff.com/jobs -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
