Question

I have a web application written completely in the usual html/css/javascript and some additional stuff using jQuery.
I also have a pretty huge program written in python which needs to act on the input provided by the user on my web app.
Currently, I am writing the input from Php onto a file and reading it in python to do my manipulations.
Is there a better to achieve this sync?
Also, I need to execute my python program as soon as some user clicks the submit button. How do I make python wait for this?

Answer 1

Your way of syncing creates quite a big overhead due to severe I/O operations on regular files, you must deal with locks, and even small load growth can cause overall system crash.

What I’d recommend you is to get acquainted with IPC techniques commonly used to exchange information between two processes:

1. In Python there’s a subprocess module that will help you to use PIPES for communication between processes which is much more reliable than using regular files. PHP also has popen function that will allow you to call python process and pass data to it for further processing (via PIPES).
2. Another way is to build a socket communication from scratch between two processes, where your PHP part will be a socket client and Python part will be a socket server (will require more work that previous way).
3. You can also use better way of queuing data for further processing (I mean better than a regular file), e.g. using Message services (there are a lot of them, RabbitMQ, Redis Pub/Sub and so on) which are definitely available for using either from Python or PHP.

There are also some techniques left out of scope, but I’ve chose those 3 ways for arranging IPC because they’re the simplest and the fastest in implementation.

You can try all of them, or some, and analyze what would be the best way in your specific case.