Question about import and sys.path
rw at smsnet.pl
Tue Nov 28 15:48:14 CET 2006
Frank Millman wrote:
> Hi all
> I am writing a business/accounting application. Once a user has logged
> in they are presented with a menu. Each menu option has a description
> and an associated file name and program name. The file name is the name
> of a .py file (impName) and the program name is the name of a class in
> that file which I instantiate to run the program (progName).
> When a menu option is selected, I execute the program like this -
> imp = __import__(impName)
> app = getattr(imp,progName)()
> All the .py files are stored in one directory, which I add to sys.path
> at the beginning of the session. It all seems to work fine.
> Now my program directory is getting cluttered, so I want to split it
> into sub-directories, one per company (it is a multi-company system). I
> can do that, and each of the subdirectories can be added to sys.path,
> so it should work as at present.
> However, I want the ability to have duplicate program names stored in
> different subdirectories. At the time of selecting the menu option I
> know which company is active, so I know which directory I want to run
> the program from, but there does not seem to be a way to tell 'import'
> to import from a particular directory.
I suggest to use module `imp`.
I assume paths like this:
the module in the company1 subdirectory:
return "%s: %s" % (__file__, self.__class__.__name__)
and the module with your menu could look like this:
def get_class(classname, impname, company):
fp, pathname, description = imp.find_module(impname, [company])
m = imp.load_module(impname, fp, pathname, description)
return getattr(m, classname)
obj = get_class("SomeClass", "prog1", "company1")()
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