Can apache run a python script which is NOT executable?

Question

I setup Ubuntu server 18.04 LTS, LAMP, and mod_mono (which appears to be working fine alongside PHP now by the way.) Got python working too; at first it gave an HTTP "Internal Server Error" message. sudo chmod +x myfile.py fixed this error and the code python generates is displayed fine. But any time the execute permission is removed from the file (such as by uploading a new version of the file), the execute bit is stripped and it breaks again.

A work-around was implemented with incrontab, where the cgi-bin folder was monitored for changes and any new writes caused chmod +x %f to be ran on them. This worked for awhile, then stopped, and seems a hokey solution at best. Perl, PHP, even ASPX do not need to be marked executable - only python.

Is there any way Apache can "run" python without the file marked as executable?

Nic3500 · Accepted Answer · 2018-10-14 01:09:03Z

1

The reason PHP works, is because the interpreter is loaded into Apache. So Apache interprets the code.

For your Python, it runs as a CGI, so the interpreter is outside of Apache.

In your Python script, you probably have a #!/usr/bin/python first line (or something similar). This tells the script to run using this interpreter. This requires executable permission on the .py file, and allows you to call myfile.py directectly.

Instead run it like this: /usr/bin/python myfile.py. This way the interpreter is the executable, and it will run myfile.py as the code.

Examples

You want to run the py file "alone":

file.py
    #!/usr/bin/python
    print("Hello")

Running it:
    ./file.py

You want to run it via the python executable, like you want via Apache:
```
file.py
    print("Hello")

Running it:
    /usr/bin/python file.py
```

edited Oct 14, 2018 at 1:09

answered Oct 13, 2018 at 1:25

Nic3500

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3 Comments

rdtsc Over a year ago

I tried all manner of this up to #!/usr/bin/python3.6 /var/www/html/myfile.py but apache still returns 500 Internal Server Error. It works if execute is set. Ideas?

Nic3500 Over a year ago

Do not put the #! when calling it from the command line. The #! should only be put on the first line of the py file when you want to execute it directly. I edited my answer with examples.

rdtsc Over a year ago

Thanks for continuing with this. Well the command is the issue, the association of cgi-scripts to .py files in the Apache config is very concise and delineated, undoubtedly for security reasons. I can't see a way to have apache spawn python myfile.py. It intrinsically runs the .py file, ./myfile.py which is why it must be marked executable. I did figure out one work-around however, which I'll share as an answer for others, but I bet there is some other, better way to do this.

rdtsc · Accepted Answer · 2018-10-16 12:06:30Z

1

I don't think Apache is capable of serving executed python scripts without the execute bit set on the .py file.

But here is a work-around: simply leave that file marked executable, but import a second python file. That second file does not need to be marked executable.

myfile.py (marked as executable and read-only - use this with apache):

#!/usr/bin/python3
# enable debugging
# helper to run the other, non-executable file
# do not add .py to the import "filename"
import myfile2

myfile2.py (marked RW only, edit this file freely):

# this is the code which can change frequently
# and does not need to be marked executable...
print("Content-type: text/html\n\n")
print("<html><head><title>Python</title></head>")
print("<body>Hello, World!</body></html>")

edited Oct 16, 2018 at 12:06

answered Oct 14, 2018 at 22:55

rdtsc

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