Download a File From SharePoint Online Using Python

How do you download a file from a SharePoint Online library using Python?

Items needed to run the script in this example:
Install and run a simple Python script.
Office365 Rest Python Client library:
https://pypi.org/project/Office365-REST-Python-Client/
SharePoint App Only Client Id and Secret:
Microsoft documentation:
https://docs.microsoft.com/en-us/sharepoint/dev/solution-guidance/security-apponly-azureacs
You can create an app principle that is limited to a single site, list, library, or a combination of them:
https://piyushksingh.com/2018/12/26/register-app-in-sharepoint/

from office365.runtime.auth.authentication_context import AuthenticationContext
from office365.sharepoint.client_context import ClientContext
from office365.sharepoint.files.file import File

app_settings = {
    'url': 'https://YOURtenant.sharepoint.com/sites/somesite/',
    'client_id': '12344-abcd-efgh-1234-1a2d12a21a2121a',
    'client_secret': 'Oamytacohungry234343224534543=',
}

context_auth = AuthenticationContext(url=app_settings['url'])
context_auth.acquire_token_for_app(client_id=app_settings['client_id'], client_secret=app_settings['client_secret'])

ctx = ClientContext(app_settings['url'], context_auth)
web = ctx.web
ctx.load(web)
ctx.execute_query()

response = File.open_binary(ctx, "/Shared Documents/Invoice.pdf")
with open("./Invoice.pdf", "wb") as local_file:
    local_file.write(response.content)

If the above script does not work, take a step back and make sure you are connected to the site.

from office365.runtime.auth.authentication_context import AuthenticationContext
from office365.sharepoint.client_context import ClientContext
from office365.sharepoint.files.file import File

app_settings = {
    'url': 'https://YOURtenant.sharepoint.com/sites/somesite/',
    'client_id': '12344-abcd-efgh-1234-1a2d12a21a2121a',
    'client_secret': 'Oamytacohungry234343224534543=',
}

context_auth = AuthenticationContext(url=app_settings['url'])
context_auth.acquire_token_for_app(client_id=app_settings['client_id'], client_secret=app_settings['client_secret'])

ctx = ClientContext(app_settings['url'], context_auth)
web = ctx.web
ctx.load(web)
ctx.execute_query()

print("Site title: {0}".format(web.properties['Title']))