problem doing unpickle in an exec statement

[Danny Shevitz]

Howdy, 

In my app I need to exec user text that defines a function. I want this
function to unpickle an object. Pickle breaks because it is looking for
the object definition that isn't in the calling namespace. 

I have mocked up a simple example that shows the problem. Run this 
first code (from create_pickle.py) to create the pickle.

create_pickle.py: (run this first)

#############################################
import cPickle

# the pickle file name
file_name = 'd:\\temp\\test1.pickle'

# define a class
class Tree(object):
	pass


def main():
	# instantiate	
	t = Tree()
		
	# create the sweet pickle
	fp = open(file_name, 'wb')
	cPickle.dump(t, fp)
	fp.close()
	
	# try to unpickle directly
	fp = open(file_name, 'rb')
	result = cPickle.load(fp)
	fp.close()
	print "unpickling directly works just fine, result = ", result

if __name__=='__main__':
	main()
#############################################

run this second:

exec_pickle.py
#############################################
# this file shows a problem with sweet pickle in an exec statement

# the pickle file name
file_name = 'd:\\temp\\test1.pickle'

# code to be turned into a function
code_text = '''
def include():
  print "this works!"
'''

# a function for creating functions
def create_fun(code_text):
	clean_dict = {} 
	exec code_text in clean_dict
	return clean_dict['include']

# include_fun is a bona fide function
include_fun = create_fun(code_text)

# this works
include_fun()


# now try to load the pickle in an exec statement
code_text = '''
def include(file_name):
  print "processing file_name: ", file_name
  import cPickle
  fp = open(file_name, "rb")
  result = cPickle.load(fp)
  fp.close()
  print "result = ", result
'''

# create the new include_fun
include_fun = create_fun(code_text)

# run it
include_fun(file_name)

#############################################

Can anyone enlighten me what I need to do to exec_pickle.py
to get this to work?

thanks,
Danny