Google Calendar Integration with Django

Researching a lot of different approaches I found out that server-to-server authentication is what I wanted. This way no user has to explicitly give permissions and acquired auth-tokens don't have to be renewed. Instead, using a service account, a server can make calls itself.

Before you can start coding, you have to setup such a service account and add it to your calendar that you want the service account to access. Google has written down the three steps to create an account here. Afterwards, go to https://calendar.google.com, locate on the left side of the screen the calendar you want to share with your new service account and click the triangle next to it. From the drop-down menu choose calendar settings. This takes you to a screen where you'll find the calendar-ID which you'll need later (so write it down) and also displays a tab at the top to share access to the calendar. As "person" insert the email address from the service account, give it the respective permissions and click save (if you don't click save the service account won't be added).

The code for this is actually pretty elegant:

import os
from datetime import timedelta
import datetime
import pytz

import httplib2
from googleapiclient.discovery import build
from oauth2client.service_account import ServiceAccountCredentials

service_account_email = '[email protected]'

CLIENT_SECRET_FILE = 'creds.p12'

SCOPES = 'https://www.googleapis.com/auth/calendar'
scopes = [SCOPES]

def build_service():
    credentials = ServiceAccountCredentials.from_p12_keyfile(
        service_account_email=service_account_email,
        filename=CLIENT_SECRET_FILE,
        scopes=SCOPES
    )

    http = credentials.authorize(httplib2.Http())

    service = build('calendar', 'v3', http=http)

    return service


def create_event():
    service = build_service()

    start_datetime = datetime.datetime.now(tz=pytz.utc)
    event = service.events().insert(calendarId='<YOUR EMAIL HERE>@gmail.com', body={
        'summary': 'Foo',
        'description': 'Bar',
        'start': {'dateTime': start_datetime.isoformat()},
        'end': {'dateTime': (start_datetime + timedelta(minutes=15)).isoformat()},
    }).execute()

    print(event)

I'm using oauth2client version 2.2.0 (pip install oauth2client).

I hope this answer helps :)

Just a note here: Although the code works, as per https://github.com/googleapis/google-auth-library-python/blob/7a8641a7f0718c0dce413436f23691e8590face1/docs/index.rst, oauth2client has been deprecated recently in favour of google-auth library - https://github.com/googleapis/google-auth-library-python/tree/edfe24602051969e32917e82bcedd2bace43e260

You can find the documentation of the new library here - https://google-auth.readthedocs.io/en/latest/user-guide.html

To use the new library, the code can be written as

import datetime
from datetime import timedelta

import pytz

from google.oauth2 import service_account

from googleapiclient.discovery import build

service_account_email = "[email protected]"
SCOPES = ["https://www.googleapis.com/auth/calendar"]

credentials = service_account.Credentials.from_service_account_file('google_calendar_credential.json')
scoped_credentials = credentials.with_scopes(SCOPES)


def build_service():
    service = build("calendar", "v3", credentials=scoped_credentials)
    return service


def create_event():
    service = build_service()

    start_datetime = datetime.datetime.now(tz=pytz.utc)
    event = (
        service.events()
        .insert(
            calendarId="primary",
            body={
                "summary": "Foo 2",
                "description": "Bar",
                "start": {"dateTime": start_datetime.isoformat()},
                "end": {
                    "dateTime": (start_datetime + timedelta(minutes=15)).isoformat()
                },
            },
        )
        .execute()
    )

    print(event)

create_event()

As I do not have enough reputation to post this as comment, I am posting this as a separate post