php called python script

Question

I've got a problem with a python script. The script itself generates a string and writes it at the end to a file. This works well when I call the python script directly.

But as soon as I call the python script from PHP with exec(), it can't write to the file anymore.

In python I simply use:

try:
    FILE = open(filename,"w")
    FILE.write(mystring)
except IOError:
    print 'cannot open', filename

and PHP calls the python script like this:

$command = 'python myscript.py input1 input2 > /dev/null &';
exec($command, $stdout, $error);

Does anyone know what to do solve the problem?

Answer 1

it can't write to the file

What error message are you getting? I notice that you are reporting an error in the Python script using a straight print to stdout, and redirecting stdout to /dev/null when running. The stderror string is a useful part of an IOError exception. You could change your except to something like this:

except IOError, err:
    sys.stderr.write("Could not open "+ err.filename + ": " + err.strerror + "\n")   

or you could use stdout and redirect the output to a real file instead of /dev/null - at least until you have nailed the problem.

Answer 2

Is filename a relative or absolute path? I would recommend using absolute paths so your script will work however it's called - for example "/home/matt/scripts/python/test.txt" is an absolute path.

This is a common error with scripts called by other scripts, or called by system events or cronjobs, etc.

Hope that helps

Answer 3

There is a system-function which you can find in PHP manual: http://php.net/manual/en/function.system.php

$var = system('python sample.py myargs', $ref);