Re: [Boa Constr] running applications

[Misner, R. <rm...@ac...>]

> By default applications use the same sys.path settings as Boa itself. =
If=20
> I want to run my app using modules located in other paths - how would =
I=20
> do that?

It depends on these "other paths" and how they are used...

On my system (WinXP / Python 2.2) Boa executes the script pointed to by =
the PYTHONSTART environment variable.  In my case, I have set up a =
script called PythonStart.py in my home folder and set =
PYTHONSTART=3DX:\PythonStart.py.  In my PythonStart module, I import =
sys, and call sys.path.append() for all the python module paths I want =
to use.  I find this is a good way to set up paths for my local =
workstation, particularly to modules I have written to do specialized =
shell-only functions that I used for experimentation and introspection.  =
But of course this method doesn't work if you need to set up these paths =
for your application to run on somebody else's workstation.

If these paths are dependant on your application rather than your =
workstation, then you could just do some sys.path.append() calls at the =
beginning of your application's main module.  Then every time you run =
it, it will set up the appropriate path.  If these paths are relative to =
your main application's directory, you can use code like this:

in main.py:
------------------
import os
import main as thismodule
sThisFilePath =3D thismodule.__file__
sThisFileDir =3D os.path.split(sThisFilePath)[0]
sPathToAdd =3D os.path.join(sThisFileDir, "MySubDir")
os.path.append(sPathToAdd)
-----end main.py------

However, if you are just trying to import or execute modules located =
under your project directory tree, then you should consider setting up =
your project as a python package.  All you have to do is create an empty =
file in each directory and subdirectory of your project and name it =
__init__.py and it will cause the local directory (and all those in the =
tree that have an __init__.py file) to be searched for modules before =
the standard python path is searched.  That way if you have a local =
module in your project that has the same name as another module in the =
sys.path, your local module is what will be loaded.  You can read more =
about packages on the python website.  They explain it better than I =
can.

In windows, there is also a PYTHONPATH environment variable, which you =
can try changing.  I have not had any success changing it so I don't =
think it is actually supported, but then maybe there was some other =
problem going on that I didn't notice.  Again, this is only for =
workstation-specific paths.  If you need your application to have access =
to the directories in question when it is run on another machine, then =
you can't use this method.

I'm pretty new to Python so maybe somebody else has better ideas?  Hope =
this helped anyway...

-Ris