Trouble accessing Gmail through API authentication

Other Questions Gmail
1

I’m trying to set up server-to-server authentication for the Gmail API, but I’m hitting a wall. I’ve got a service account and the credentials file, but something’s not clicking.

Here’s what I’m working with:

def read_gmail():
    AUTH_SCOPE = ['https://www.googleapis.com/auth/gmail.readonly']
    CREDS_FILE = 'my_secret_creds.json'
    auth = service_account.Credentials.from_service_account_file(
            CREDS_FILE, scopes=AUTH_SCOPE)
    print(auth)
    gmail = build('gmail', 'v1', credentials=auth)
    inbox = fetch_messages(gmail, 'me', '[email protected]')
    first_message = inbox[0]['id']

But I keep getting this error:

HttpError 400: Bad Request
Login Required

I’ve looked at the Google API docs and tried a bunch of StackOverflow solutions, but I’m still stuck. Any ideas on what I’m doing wrong or how to fix this? Thanks for any help!

2

Hey Liam23, I’ve encountered similar issues before. It appears that the core problem in your code is that you’re not impersonating a user when using a service account. To address this, you’ll need to include the user’s email, which the service account should impersonate. For example, modify your code as follows:

creds = service_account.Credentials.from_service_account_file(
    CREDS_FILE, scopes=AUTH_SCOPE)
creds = creds.with_subject('[email protected]')
gmail = build('gmail', 'v1', credentials=creds)

Remember to replace ‘[email protected]’ with the actual email of the user whose Gmail account you’re trying to access. Also, ensure that you have properly enabled domain-wide delegation on your service account and set up the necessary permissions in the Admin console. This adjustment should help you overcome the ‘Login Required’ error.

3

I see you’re having trouble with the Gmail API authentication. From my experience, the ‘Login Required’ error often pops up when you’re not properly impersonating a user with your service account.

Make sure you’ve enabled domain-wide delegation for your service account in the Google Cloud Console. In your code, add a line to impersonate the user by using:

creds = creds.with_subject(‘[email protected]’)

Replace ‘[email protected]’ with the actual email you’re trying to access. Also, double-check that you have the necessary permissions set up in the Google Admin Console.

If you’ve done all this and still encounter issues, consider using OAuth 2.0 for user authentication as an alternative method. This might simplify the process in some setups.

4

yo liam23, i’ve had similar probs. looks like ur missing the user impersonation bit. try addin this line before buildin the service:

creds = creds.with_subject(‘[email protected]’)

make sure to swap that email with the actual account ur tryin to access. also double check ur service account has the right permissions set up in admin console. good luck!