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Send data from php on webserver to c++ app on local machine
I'm working on a project that needs to get data from a php script on a webserver and send it to a c++ app that is running on a local hardrive (not same computer as webserver). I know there are plenty of resources on wiritng sockets in php and c, however I need help understanding the specifics of making this work (if it is possible). First, the machine runninig the script will be connected to the internet of course. I know how to find the ip address of my pc, but I cannot seem to create a connection from a php script to it. Are there settings I need to alter or could there be a block from the network i'm connected to? How do I choose a port and find out if it is open to send and receive on both ends?
My hack for the moment is to save the data i need to a file on the server and have the c app check that file. It does not seem to make sense to do it this way when I do not need to save the data but just transmit it. I also want to have the c app just listening for incoming data, not actively accessing a file ona server.
Thanks for any help!
My hack for the moment is to save the data i need to a file on the server and have the c app check that file. It does not seem to make sense to do it this way when I do not need to save the data but just transmit it. I also want to have the c app just listening for incoming data, not actively accessing a file ona server.
Thanks for any help!
ASKER
Thanks for the comments!
Well, this for digital art installation that allows multiple users to connect via mobile phone to the application which is projected inside a gallery. It uses vxml to capture keypad input and the php script would then send it (potentially) to the c++ application. The cellphone becomes a remote control to move things around in the projection so it needs to have a quick response time to the users input.
Right now it functions by saving the data on the server and looking at that data in intervals (I think this is what you are suggesting). This works fine with some delay, but I thought it would be faster and more logical if the php (it could also be a perl or c app on the webserver) sent to the c++ app directly. Does that seem to make sense?
The webserver is on a university server and the machine running the app will be on seperate network inside a gallery...
Well, this for digital art installation that allows multiple users to connect via mobile phone to the application which is projected inside a gallery. It uses vxml to capture keypad input and the php script would then send it (potentially) to the c++ application. The cellphone becomes a remote control to move things around in the projection so it needs to have a quick response time to the users input.
Right now it functions by saving the data on the server and looking at that data in intervals (I think this is what you are suggesting). This works fine with some delay, but I thought it would be faster and more logical if the php (it could also be a perl or c app on the webserver) sent to the c++ app directly. Does that seem to make sense?
The webserver is on a university server and the machine running the app will be on seperate network inside a gallery...
I'd say this sounds like it should be done using a continuous delivery protocol like IRC or similar instead of HTTP, so that your PHP can send data immediately as it arrives. You'll get much better responsiveness that way. However, you can't reliably run a PHP script continuously from a web server - it needs to be a standalone process.You'll need to open a socket that the PHP process can connect to and keep open. You can pass info to it via shared memory and kick it into action by sending it signals from scripts that are exposed to the web. This way you can do the 'push' technique you're after - maximum efficiency, minimum latency
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ASKER
great, yess that sounds like the approach I'm looking for. I'm going to give these suggestions a try. thanks!
- In either case, yes, firewall or proxy could get in the way of opening a socket. Depending on where the client PC is, opening a particular port could be blocked by the PC, or company (if internal) firewall, or ISP (if home) firewalling.
- The advantage of having the client PULL is that your webserver is already running, and accessible. Thus, opening an HTTP connection is already possible -- so you use it.
- The C++ app and the webserver can obviously use a number of security methods to ensure safety of data -- assuming it's data that needs to be secured. That, of course, would be a question in and of itself! ;)
I just had a user trying to use sockets with the opposite-direction problem -- he was trying to grab a page from a public website, but turned out HE was behind a firewall and proxy that was blocking the connection...
How often does data need to be transmitted between the machines? Can you poll instead of push? i.e., is there a reason you are trying to push from the server specifically? I can think of things like say e-commerce orders on a website, and you want them pushed directly to you -- however, in most situations, you could do a check every 5 minutes, and batch-download any updates since the last check.
If you can detail the basic process, and where the client machine resides (home, work, etc.), I can give even more specifics. But I think the above outlines the basic thought process.
-=d