override urllib3 allowed chars so requests will accept otherwise invalid characters

urllib3_requests_override_chars.py

import requests
import urllib3.util.url

# ref: Lyle at https://github.com/psf/requests/issues/6115#issuecomment-1172198984
def hook_invalid_chars(component, allowed_chars):
    # handle url encode here, or do nothing
    return component


# Method1:
# Warning: this is a hack to override
# urllib3.util.url._encode_invalid_chars = hook_invalid_chars

# Method2:
# ref: Tomi at https://stackoverflow.com/a/77256282/22707650
# Warning: this is a hack to make urllib3 allow otherwise invalid characters
urllib3.util.url._QUERY_CHARS.add('{')
urllib3.util.url._QUERY_CHARS.add('}')

url_base = 'http://127.0.0.1:5470/thing/page'
url_query = '{item1}{item2}{item3}'

with requests.Session() as sess:    
    # Note: need to use both the hack above and a prepared request
    req = requests.Request(method='GET', url=url_base)
    prep = req.prepare()
    prep.url += f'?{url_query}'
    
    resp = sess.send(prep)