Python Adal - Can't use Access Token to retrieve Outlook Messages - python-3.x

Question

I've recently been attempting to port a email extraction process from Powershell to Python using the Azure active directory for Python library. I've been attempting to use the acquire_token_with_client_credentials function to do this but I've hit a snag.
I can use the code below to return an access code but I can't use the resulting token to return any mailbox items.
I've managed to create a native app and successfully access messages using acquire_token_with_username_password but can't get that set of code to work on my remote desktop as it prints an error reading:
"Due to a configuration change made by your administrator, or because you moved to a new location, you must use multi-factor authentication"
I've had a ready of the client credentials flow but still can't get the example below to work. Can anyone see where I'm going wrong?
def test8():
import adal
import requests
authority_url = "https://login.microsoftonline.com/"+lf_tenantid
context = adal.AuthenticationContext(
authority_url,
validate_authority=True,
api_version=None
)
resource = 'https://outlook.office.com/'
token = context.acquire_token_with_client_credentials(
resource=resource,
client_id = etl_clientid2,
client_secret = etl_clientsecret2
)
access_token = token['accessToken']
print(token)
#######################################NONE OF THIS PART WORKS
#######################################
#######################################
folder_id = etl_folderid
url = "https://outlook.office.com/api/v2.0/me/MailFolders/"+folder_id+"/messages"
headers = {
'Authorization': 'Bearer '+access_token
}
r = requests.get(url, headers=headers)
print(r)

Answer 1

For anyone who's interested, this is the code I used to solve my access token issue:
def save_windows_refreshtoken(app_name, client_id, client_secret):
#import adal
#import requests
import json
import pandas as pd
# OAuth endpoints given in Outlook API documentation
authorization_base_url = 'https://login.microsoftonline.com/common/oauth2/authorize'
token_url = 'https://login.microsoftonline.com/common/oauth2/token' #provides a refresh and access token
redirect_uri = "http://localhost:8000"
from requests_oauthlib import OAuth2Session
outlook = OAuth2Session(client_id,redirect_uri=redirect_uri)
# Redirect the user owner to the OAuth provider (i.e. Outlook) using an URL with a few key OAuth parameters.
authorization_url, state = outlook.authorization_url(authorization_base_url)
print('Please go here and authorize,', authorization_url)
#The above redirects you to a localhost page (which is blank) but returns a string containing a code which can be used below
#rememebr the search for "&" because there's a couple of bits of data after the code that need to be deleted from the code string before it can be used
# Get the authorization verifier code from the callback url
redirect_response = input('Paste the full redirect URL here:')
# Fetch the access token
token = outlook.fetch_token(token_url,client_secret=client_secret,code=redirect_response)
#convert the returned token json into a dataframe
j_dump = json.dumps(token, sort_keys=True,indent=4, separators=(',', ': ')) #pull out the value data from the json file, messages are stored in value
df = pd.read_json(j_dump) #read the json file into a dataframe
first_row = df.iloc[0] #pull the first row so we can format a new table from it
d = {
'app_name' : pd.Series([app_name]),
'refresh_token' : pd.Series([first_row.refresh_token])
}
data = pd.DataFrame(d)

Answer 2

You are getting messages with acquire_token_with_username_password() because you are getting a token for given resource via user credentials.
Because client credential flow is used for back channel (server to server communication), so user is not involved in that and you are getting service principal token.
I would suggest to use on behalf of flow or authorization code flow (acquire_token_with_authorization_code) to get a token for a given resource via authorization code for a server app and call the outlook api to read messages.
Below is the link (Outlook Mail API and Python):
https://github.com/jasonjoh/python_tutorial/tree/outlook-api
Python adal library supports other authentication methods. Below is the documentation link:
https://adal-python.readthedocs.io/en/latest/
We suggest that Office 365 services, such as OneNote, Outlook, Excel, OneDrive, Microsoft Teams, Planner, and SharePoint, are now exposed in Microsoft Graph.
https://learn.microsoft.com/en-us/previous-versions/office/office-365-api/