How to keep resources (not serializable) during a session

mbernhard

We have a legacy cobol application for which instead of using terminal/curses we are building a web interface. The PHP session should maintain a communication during a session with the legacy application which it started in the background.

I noticed that resources are not serializable so the first prototype uses mySQL for the field information and a IPC message queue between them to trigger the send/receive chat. By saving the message queue-id in the session I can reconnect to it on the users browser submit.
Although this works great, I would like to have a socket connection during the session to implement the communication.

How can I reconnect to a socket during a session ?
Does a PHP package (PHP Core) exist wo could maintain open connections between PHP calls ?

I searched a lot but didn't find any answers or even people dealing with this kind of problem. So any help or directions are very welcome.

Mario

rvdavid

Hi,

A little hazy on this, but I'd say that pfsockopen() is your best bet if you haven't looked at it already.

Good luck.

Regards,

MarkR

You simply cannot do this - it is fundamental to the way PHP works. It uses a shared-nothing architecture - absolutely nothing is shared between web server threads.

Moreover, even if you could, it would have no way of knowing when a connection came in, immediately, which session it belonged to - therefore it might pick up the wrong session's resource and all go wrong.

Using pfsockopen() might appear to work, but actually won't because it will pick up an arbritary session, not necessarily one belonging to the same user session. Persistent connections are held by PHP per web server thread, not by session. Therefore, they must be stateless (or have all state reset on each request) in order to obtain consistent results.

If you need a stateful session, you must use an intermediate process to maintain this.

Mark

mbernhard

thanks for pointing me towards pfsockopen().

Using pfsockopen() might appear to work, but actually won't because it will pick up an arbritary session
Each session communicates with a seperate legacy application on a unique port. So this could work.

I did some more digging yesterday and came up with another idea:
The legacy application listens on a port and accepts connections in a while loop.
On each browser submit PHP opens a new connection to the legacy application to communicate and closes the connection. The legacy application returns to accept the next connection.
For the socket I could use UNIX sockets, so the defined port is a known path (eg. "sock-sid"). The sid is written in an environment variable prior starting the legacy application in the background.

If you need a stateful session, you must use an intermediate process to maintain this.
I thouht a long time about such a solution but the problem how I communicate with the intermediate process is the same.

I feel much better with sockets than with message queues what cleanup considers.

Once more thanks for the help.