Question

I am using google app engine and I am trying to basically allow users to upload code, where it will later be executed by the server. I also have to be able to send variables to the scripts, which is why initially when I was running everything on my desktop, I Imported everything dynamically (as in- the name of the script is stored in a variable). But now I can not do this because of the filesystem in the google app engine environment.

I already have a database setup so that I can get the code in plain-text. But now I would like to know if there was any way that I could import a python script, not from a file but from a variable containing python code.

For example, If this was the plain-text code, how could I get this to execute properly:

code = """
def Main(var):
    print "you entered: " + var
"""

Answer 1

First, create a module for the code to live in:

# define module_name somewhere
import types
module = types.ModuleType(module_name)

You’ll probably want to register that module, too:

import sys
sys.modules[module_name] = module

Then compile the code:

# source should the code to execute
# filename should be a pseudo-filename that the code's from
# (it doesn't actually have to exist; it's used for error messages)
code_object = compile(source, filename, 'exec')

Then execute the code object in the context of the module:

exec code_object in module.__dict__