'Some Annoyances' Thread RSS Feed

Some Annoyances

Sat, 23 Oct 2004 19:33:25 -0700

Hey, I spent some time and setup my local iis web server to facilitate the creation of ASP pages via Python.

First off, it took me a while to integrate the concept of packages.

I find myself having to place this code at the top of my file ...

<%
import sys

# Setup Environment Path ######
path = "c:\development"

try:
	sys.path.index(path)

except ValueError:
	sys.path.append(path)

###############################
%>

Because A: I do not feel like setting the PYTHONPATH environment variable (because I would have to literally modify it for each web app that uses python) and B: IIS loses any information you append to the path when you restart the server process.

The other annoyance I came across involves some sort of mysterious caching. When I set up a module called ASP.py in a folder called cls, I can easily import it like so:

from cls import ASP

Initially calling functions from this module ran fine, but say I removed a function or modify a function; the changes do not reflect. I literally have to kill the web server process, which usually means restarting iis.

I am wondering if this kind of behavior exists in python programs that are not strapped to a web server process? I can not help wondering if there is someway to invalidate a python module, so that the scripting engine must recompile it.

Re: Some Annoyances

Mon, 25 Oct 2004 08:25:29 -0700

: Hey, I spent some time and setup my local iis web server to facilitate the creation of ASP pages via Python.
:
: First off, it took me a while to integrate the concept of packages.
:
: I find myself having to place this code at the top of my file ...
:
:

: <%
: import sys
: 
: # Setup Environment Path ######
: path = "c:\development"
: 
: try:
: 	sys.path.index(path)
: 
: except ValueError:
: 	sys.path.append(path)
: 
: ###############################
: %>
:

:
: Because A: I do not feel like setting the PYTHONPATH environment variable (because I would have to literally modify it for each web app that uses python) and

Can't help you here other that to suggest some kind of .ini file with an initialization function.

: B: IIS loses any information you append to the path when you restart the server process.

That's because when you "import sys" you are just loading the sys module into memory. The appending of paths to sys.path is just adding another item to the in-memory list. I'm sure you knew that. Is there a way to hook the server process startup to initialize your sys.path there?

: The other annoyance I came across involves some sort of mysterious caching. When I set up a module called ASP.py in a folder called cls, I can easily import it like so:
:
:

: from cls import ASP
:

:
: Initially calling functions from this module ran fine, but say I removed a function or modify a function; the changes do not reflect. I literally have to kill the web server process, which usually means restarting iis.
:
: I am wondering if this kind of behavior exists in python programs that are not strapped to a web server process? I can not help wondering if there is someway to invalidate a python module, so that the scripting engine must recompile it.

That's the normal way Python handles modules. The interpreter will only load a module the first time it encounters an "import" statement. The reason is to avoid recursive reference loops. If you "import A" and A does "import B" but B does "import A" then you can see the problem. You can force the interpreter to reload a module using the reload() function:

import cls.ASP as ASP
ASP = reload(cls.ASP)

infidel

$ select * from users where clue > 0
no rows returned

Re: Some Annoyances

Mon, 25 Oct 2004 09:14:49 -0700

: : Hey, I spent some time and setup my local iis web server to facilitate the creation of ASP pages via Python.
: :
: : First off, it took me a while to integrate the concept of packages.
: :
: : I find myself having to place this code at the top of my file ...
: :
: :

: : <%
: : import sys
: : 
: : # Setup Environment Path ######
: : path = "c:\development"
: : 
: : try:
: : 	sys.path.index(path)
: : 
: : except ValueError:
: : 	sys.path.append(path)
: : 
: : ###############################
: : %>
: :

: :
: : Because A: I do not feel like setting the PYTHONPATH environment variable (because I would have to literally modify it for each web app that uses python) and
:
: Can't help you here other that to suggest some kind of .ini file with an initialization function.
:
: : B: IIS loses any information you append to the path when you restart the server process.
:
: That's because when you "import sys" you are just loading the sys module into memory. The appending of paths to sys.path is just adding another item to the in-memory list. I'm sure you knew that. Is there a way to hook the server process startup to initialize your sys.path there?
:
: : The other annoyance I came across involves some sort of mysterious caching. When I set up a module called ASP.py in a folder called cls, I can easily import it like so:
: :
: :

: : from cls import ASP
: :

: :
: : Initially calling functions from this module ran fine, but say I removed a function or modify a function; the changes do not reflect. I literally have to kill the web server process, which usually means restarting iis.
: :
: : I am wondering if this kind of behavior exists in python programs that are not strapped to a web server process? I can not help wondering if there is someway to invalidate a python module, so that the scripting engine must recompile it.
:
: That's the normal way Python handles modules. The interpreter will only load a module the first time it encounters an "import" statement. The reason is to avoid recursive reference loops. If you "import A" and A does "import B" but B does "import A" then you can see the problem. You can force the interpreter to reload a module using the reload() function:
:
: import cls.ASP as ASP
: ASP = reload(cls.ASP)
:
:
:
: infidel
:
:

: $ select * from users where clue > 0
: no rows returned
:

:
:
-You Wrote-
"Is there a way to hook the server process startup to initialize your sys.path there?"

Well there is a file in all asp projects called global.asa. There is an Application_Start event in this file (which fires at the beginning of the web process creation), which I suppose could house the code. I'll have to see if python can hook into it. The solution I used so far, so that I am not rewritting the code, is to use an include statement ...

<!-- #include file="init.asp" -->

<%
# Other Python Code Here
%>