How to enable CORS in python - python-2.7

Question

Let me start this with, I do not know python, I've had maybe 1 day going through the python tutorials. The situation is this. I have an angular app that has a python app hosted with Apache on a vm in an iframe. I didn't write the python app, but another developer wrote me an endpoint where I am supposed to be able to post from my angular app.
The developer who made the python endpoint is saying that there is something wrong with my request but I am fairly certain there isn't anything wrong. I am almost 100% certain that the problem is that there are no CORS headers in the response and/or the response is not set up to respond to the OPTIONS method. Below is the entirety of the python endpoint:
import os, site, inspect
site.addsitedir(os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))+"/../")
import json
from datetime import datetime
import pymongo
from Config import Config
def application(environ, start_response):
response = environ['wsgi.input'].read(int(environ['CONTENT_LENGTH']))
if response:
json_response = json.loads(response)
document = {
'payment_id': json_response['payment_id'],
'log': json_response['log'],
'login_id': json_response['login_id'],
'browser': environ.get('HTTP_USER_AGENT', None),
'ip_address': environ.get('REMOTE_ADDR', None),
'created_at': datetime.utcnow(),
}
client = pymongo.MongoClient(Config.getValue('MongoServer'))
db = client.updatepromise
db.PaymentLogs.insert(document)
start_response('200 OK', [('Content-Type', 'application/json')
return '{"success": true}'
start_response('400 Bad Request', [('Content-Type', 'application/json')])
return '{"success": false}'
I have attempted the following to make this work: I added to both start_response functions more headers so the code looks like this now:
start_response('201 OK', [('Content-Type', 'application/json',
('Access-Control-Allow-Headers','authorization'),
('Access-Control-Allow-Methods','HEAD, GET, POST, PUT, PATCH, DELETE'),
('Access-Control-Allow-Origin','*'),
('Access-Control-Max-Age','600'))])
Not: I did this both with the 200 and the 400 response at first, and saw no change at all in the response, then just for the heck of it, I decided to change the 200 to a 201, this also did not come through on the response so I suspect this code isn't even getting run for some reason.
Please help, python newb here.
Addendum, i figured this would help, here is what the Headers look like in the response:
General:
Request URL: http://rpc.local/api/payment_log_api.py
Request Method: OPTIONS
Status Code: 200 OK
Remote Address: 10.1.20.233:80
Referrer Policy: no-referrer-when-downgrade
Response Headers:
Allow: GET,HEAD,POST,OPTIONS
Connection: Keep-Alive
Content-Length: 0
Content-Type: text/x-python
Date: Fri, 27 Apr 2018 15:18:55 GMT
Keep-Alive: timeout=5, max=100
Server: Apache/2.4.18 (Ubuntu)
Request Headers:
Accept: */*
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Access-Control-Request-Headers: authorization,content-type
Access-Control-Request-Method: POST
Connection: keep-alive
Host: rpc.local
Origin: http://10.1.20.61:4200
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Answer 1

Here it is. Just add this to the application right at the beginning:
def application(environ, start_response):
if environ['REQUEST_METHOD'] == 'OPTIONS':
start_response(
'200 OK',
[
('Content-Type', 'application/json'),
('Access-Control-Allow-Origin', '*'),
('Access-Control-Allow-Headers', 'Authorization, Content-Type'),
('Access-Control-Allow-Methods', 'POST'),
]
)
return ''

Answer 2

For Python with CGI, I found this to work:
print '''Access-Control-Allow-Origin: *\r\n''',
print '''Content-Type: text/html\r\n'''
Don't forget to enable CORS on the other side as well, e.g., JavaScript jQuery:
$.ajax({ url: URL,
type: "GET",
crossDomain: true,
dataType: "text", etc, etc