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utilities to help bootstrap deployment of WSGI applications using isapi-wsgi

Project description


ISAPIWSGIHelper is a small command line script and some helper utilities to help bootstrap deployment of WSGI applications using isapi-wsgi with Microsoft IIS.


The following should be installed:

  • Python

  • Python Win32 Extensions

In addition, python’s scripts directory should already be in your path. If commands like easy_install or pip already function, you should be good to go.

You should be familiar with IIS and how to load ISAPI extensions into websites and virtual directories. You should be familiar with isapi-wsgi setup.


  • argparse

  • isapi_wsgi


easy_install ISAPIWSGIHelper or pip install ISAPIWSGIHelper will get the job done.

Note: ISAPIWSGIHelper should be installed in python’s site-packages directory, not in a virtualenv.


The “iwhelper” command is installed when installing the ISAPIWSGIHelper package.

A virtualenv is recommended, but not required:

> cd c:\somewhere\myproj-venv

> virtualenv .

> iwhelper

The above will result in a virtualenv with the addition of a isapi-wsgi directory in the root of the venv. Edit isapi-wsgi\\ according to the comments in that file.

Then, setup your website or a virtualdirectory with a wildcard mapping that uses isapi-wsgi\\__loader.dll.


The isapi-wsgi directory created by the iwhelper command results in a setup with the following features:

  • Easy creation of per-project isapi-wsgi bootstrap directories through the

    iwhelper command (see above)

  • Exceptions are caught and handled appropriately. No more cryptic 500 status

    responses from IIS.

    • exceptions instantiating the application are initially hidden but can

      be displayed to the browser with a configuration change in

    • exceptions encountered when making a request to the application are

      logged to a file in the isapi-wsgi directory.

  • provides a simple bridge between isapi-wsgi and your application

  • provides a mechanism for loading a virtualenv’s site-packages dir

Special Troubleshooting w/

If push comes to shove and you just can’t figure out why your application isn’t working, provides a special mechanism for running your setup in a python web server which will give you better exception messages and automatic reloading of your python files when they are changed. See the note at the bottom of for details.

A Note About App Pools

I use a different app pool for each python website. When troubleshooting, I set the app pool to auto-recycle after one request. This is a close equivalent to auto-reloading in various python development web servers. Just remember to turn it off before going to production usage or your performance will suffer tremendously.

Questions & Comments

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Current Status

Works for me. :)

The development version is installable with easy_install ISAPIWSGIHelper==dev.

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