When calling a Python script from a PHP script, temporary file that is created on a console run, is not created via the PHP invocation.

Question

Scenario:

I have a php page in which I call a python script.

Python script when run on the command line (Linux) shows output on the command line, as well as writes the output to a file.

Python script when run through php, doesn't do either.

Elaboration:

I use a simple system command in PHP to run the python script as:

/var/www/html/1.php: system('/usr/python/bin/python3 ../cgi-bin/tabular.py 1');

/var/www/cgi-bin/tabular.py --This python file basically parses a data file, uses python's regular expression to search for specific headings and outputs the headings to the stdout, as well as write it to a file.

This python script has a few routines in it which get executed, so I put print statements to debug. I noticed only a few initial print statements' output in the PHP page, all the ones from the function that actually does something are not seen.

Also, as part of my test, I thought well the py script is in a different folder so let me change it to the /var/www/html folder, no go.

I hope I captured the problem statement with sufficient detail and someone is able to reproduce this issue at their end. If I make any progress on this one myself, I'll annotate this question. Thanks everyone.

Gaurav

Answer 1

Check that the user the python script is running is has write permissions in CWD. Also, try shell_exec() or passthru() to call the script, rather than system().

Answer 2

A permission problem is most likely the case.

If apache is running as apache, then it will not have access to write to a file unless

1. The file is owned by apache
2. The file is in the group apache and group writable
3. The file is world writable

This is a "sticky" problem on a multi-user machine, as different people have access to Apache.

Try chmod 666 output.txt on the file and then re-run your test.

---

Considerations:

1. Have the python script write the output to a database
2. Use PHP's popen functionality to open the process and communicate over pipes
3. Re-write using PHP's regular expressions
4. Write the output file to /tmp and then read the results using PHP as soon as the python script is done.
5. etc...

Answer 3

I bet your py script has some bug which couses it to break when called from inside PHP. Try

passthru('/usr/python/bin/python3 ../cgi-bin/tabular.py 1 2>&1');

to investigate (notice 2>&1 which causess stderr to be written to stdout).

Answer 4

Hi guys,

I have an almost identical problem. My python script loggs a bunch of stuff and produces about 10 output files. It also has functions which generate new files. So I have two questions:

• is it possible to change the context which appache is running in?
• is there another way to deal with these permission issues, such that log files can be written to and new files can be created?

Thanks for all and any help! :)