Interface with running applications in PHP?

问题:

I would like to know if there is any way to communicate with a running console program (preferably running on Linux / Debian) via PHP. I am currently trying to create a webinterface for a little (existing) console Java program and I have no idea if there is any way I could do this. Could I "inject" a piece of code, lets say, a remote control module, and then use this to "remote-control" the script via PHP? (It would be great if the existing .jar file wouldn't be changed / just injection, no reprogramming)

I am grateful for every piece of advice!

回答1:

If the running program has no communication interface, then you can't communicate with it. If it does however, then the answer very much depends on how the program receives external input.

If the program contains a network listening thread (daemon), then you can communicate with it on the loopback interface using CURL or raw sockets from PHP.

Other ways of communicating with the program would be to share access to a file (PHP writes the file, Java reads it) or via a database.

The database would be the best option - it is thread safe and both PHP and Java have excellent MySQL support (Java via JDBC).

If, however you do not need to actually interface with the running program only merely need to start/stop/restart it, you can do this with the system() function in PHP.

回答2:

If the Java program just runs and outputs to console, then you can do it easily enough, something like this:

$output = system( "java com.yourcompany.package.RunnableClass" ); 
print $output;

Assuming that the user who is running PHP has access to the Java binary of course, and that you have permission to access the JAR file.

Accessing a running program is a bit more difficult. Most programs will not have this built in by default (nor should they - giving access to random external processes in many cases is not desirable). If it does, though, you are in good shape. If it doesn't, and you can change the Java code, then you're good. If not, then you may be out of luck.

If that is the case, another good approach might be to see what resources the Java code is accessing, and how it is accessing them. Then you can write something similar in PHP. Obviously this is not ideal as you'll be re-inventing the wheel, but if you need to get to the data or whatever it is, and can't use any of the approaches above, it will work.