通过 PHP 脚本运行 python 脚本不起作用

Question

So basically, I am trying to run some preliminary tests for a website I will be building. There will be downloads through the site, possibly for the same resource by different users, possibly nearly or at the same time. I want to implement a lock manager of sorts to prevent repeated downloads of a resource when one is already in progress.

The test I am running is just to see if this is even possible. What I am specifically testing for right now is if I begin running a program, if I attempted to open the program again would it open a completely new instance or go to the already open instance. I am doing to this to try and see if user 1 makes changes in their program, if the second user opens their program, they will see those change; otherwise they might not see the changes if they open up a completely new instance of a program.

PHP

exec(escapeshellcmd("C:\Program Files\Python 3.7\python.exe Test2Php.py 0 Testing"), $o1, $r);
echo $r;
var_dump($o1);

Python

#!/usr/bin/env python

import sys

arr = []

t = sys.argv[1]
if (t == '0'):
arr = [sys.argv[k] for k in range(2, len(sys.argv))]
print("if")
else:

print(str(len(arr)))

The problem is the script doesn't return any output at all! It doesn't run either. I tested this by having the python program write a file at the end of successful execution. I have tried shell_exec, passthru, etc. The program itself works when run through command line, but not in any scripts I have made.

I am using a WAMP server on windows.

EDIT:

For anyone else dealing with this. Make sure you have the default Python package in your system path variable. You can do this easily by installing the latest version of python and choosing add to system path. Uninstall anaconda or whatever else may be in the way of the system path and enjoy. Also make sure you find where the python exe is and use the full path to it.

Answer 1

Your list comprehension will get out of range since you can never do lst[len(lst)] without getting an IndexError . The str() wrapper isn't necessary to print len(arr) .

Instead, use a slice of [:2] to remove the first 2 elements:

#!/usr/bin/env python

import sys

arr = []

t = sys.argv[1]

if t == '0':
    arr = sys.argv[2:]
    print("if")
else:
    print(len(arr))