Network Programming in .NET

If you’re trying to run a Flask based Python Web app in IIS, and you get the following error,

Traceback (most recent call last):
File “C:\Python37\wfastcgi.py”, line 790, in main
env, handler = read_wsgi_handler(response.physical_path)
File “C:\Python37\wfastcgi.py”, line 630, in read_wsgi_handler
handler = get_wsgi_handler(os.getenv(“WSGI_HANDLER”))
File “C:\Python37\wfastcgi.py”, line 613, in get_wsgi_handler
raise ValueError(‘”%s” could not be imported%s’ % (handler_name, last_tb))
ValueError: “index.app” could not be imported: Traceback (most recent call last):
File “C:\Python37\wfastcgi.py”, line 597, in get_wsgi_handler
handler = __import__(module_name, fromlist=[name_list[0][0]])
File “.\index.py”, line 1, in <module>
from flask import Flask
ModuleNotFoundError: No module named ‘flask’

Then, here was my solution.

1. Activate the virtualenv by typing myApp\Flask\Scripts>activate
2. open a Python terminal, by typing python
3. type import sys
4. type print(sys.path)
5. Copy all the paths (remove the escaping, and put ;’s instead of commas)
6. Go to IIS > FastCGI Settings > Edit > Environment variables
7. Then enter all the paths into the PYTHONPATH variable.

For reference, here is the github repo:

https://github.com/infiniteloopltd/HelloWorldFlask