【Google Calendar API v3】get events list with OAuth 2.0 & Rest

It took me some time to learn about the Google Calendar API V3 and I have encountered some problems. So it is necessary to summary the steps, just take the 'event list' as an example.

The event list API is here: https://developers.google.com/google-apps/calendar/v3/reference/events/list

Details of using OAuth 2.0 for Login is here: https://developers.google.com/accounts/docs/OAuth2Login

Assumption: you have alreay registered your app and turn the Calendar API 'ON' in the 'API & auth' sidebar.

Note: The request needs authorization and I use OAuth 2.0, here are the steps.

Step 1.  Send an Authentication Request to Google

HTTP GET: https://accounts.google.com/o/oauth2/auth?

client_id=XXXXXXXXX&

response_type=code&

scope=https://www.googleapis.com/auth/calendar&

redirect_uri=XXXXXXXXX&

login_hint=XXXXXX

client_id: can be seen in your Google Cloud Console.

redirect_uri: also in your Google Cloud Console, you must write it down in your registered apps page.

login_hint=google account

Then your will find the code parameter in the redirect uri.

Step 2. Exchange Code for Access Token and ID Token

Use the code you got in the last step to post request. The actual request might look like:

POST /o/oauth2/token HTTP/1.1Host: accounts.google.comContent-Type: application/x-www-form-urlencodedcode=4/P7q7W91a-oMsCeLvIaQm6bTrgtp7&client_id=8819981768.apps.googleusercontent.com&client_secret={client_secret}&redirect_uri=https://oauth2-login-demo.appspot.com/code&grant_type=authorization_code

I use the Chrome Plugin Rest Client to post the request and get access token.

Then you will get the access_token in the response.

Step 3. Get Events List NOW!

With the access_token, you are able to request the event list according to Google Calendar API.
The whole HTTP GET URI is like:

https://www.googleapis.com/calendar/v3/calendars/{your calendar id}/events?

code=XXXXXX&

client_id=XXXXXX&

client_secret=XXXXXX&

redirect_uri=XXXXX&

grant_type=authorization_code

&access_token=XXXXXXXX

{your calendar id} is your google account, looks like [e-mail]

Then you will get the JSON response!