How to implement a Google Calendar API-based system

✅ High-Level Overview

You will:

  1. Register your website/app with Google (Google Cloud Console)
  2. Enable Google Calendar API and get API keys / OAuth 2.0 credentials
  3. Implement OAuth 2.0 so users can authorize your site to access their calendars
  4. Use the Calendar API to display calendars, create, update, or delete events directly on your site

✅ Step 1: Set Up Google Cloud Project

  1. Go to Google Cloud Console.
  2. Create a new project.
  3. Enable the Google Calendar API:
    • In the left sidebar, navigate to APIs & Services ➜ Library ➜ Search for Google Calendar API ➜ Click Enable.

✅ Step 2: Create OAuth 2.0 Credentials

  1. Go to APIs & Services ➜ Credentials.
  2. Click Create Credentials ➜ Select OAuth client ID.
  3. Set up OAuth consent screen:
    • Application name (Your Website Name)
    • Add scopes (we'll talk about these later)
    • Authorized domains (your website domain)
  4. Choose Web Application.
  5. Under Authorized redirect URIs, add the URI your site will use to handle the OAuth callback. Example:
    arduino
    https://www.yourwebsite.com/oauth2callback
  6. Google will generate a Client ID and Client Secret.
  7. Save these securely!

✅ Step 3: Set Up OAuth 2.0 Flow (User Authorization)

When Jack clicks a button to “Connect Google Calendar”, he’ll:

  1. Be redirected to Google’s OAuth 2.0 screen.
  2. Approve the scopes (permissions) you request.
  3. Get redirected back to your site with an authorization code.

Example Flow:

  • Your server exchanges the authorization code for an access token (and optionally a refresh token).

➡️ The access token allows you to make API calls on Jack’s behalf.

✅ Step 4: Define the OAuth Scopes You Need

Choose scopes based on what actions users will perform:

For your scenario, calendar.events is sufficient for creating, editing, deleting events.

✅ Step 5: Make API Calls (Create, Edit, Delete Events)

Once Jack has authorized your app:

  • Use his access token to make RESTful API calls to Google Calendar API.

Example: Create an Event (POST request)

bash
POST https://www.googleapis.com/calendar/v3/calendars/{calendarId}/events Authorization: Bearer {access_token} Content-Type: application/json

Request Body:

json
{ "summary": "Team Meeting", "location": "Zoom", "description": "Discuss project updates.", "start": { "dateTime": "2025-03-17T10:00:00-07:00", "timeZone": "America/Phoenix" }, "end": { "dateTime": "2025-03-17T11:00:00-07:00", "timeZone": "America/Phoenix" }, "attendees": [ {"email": ""} ] }

Example: Update an Event (PATCH request)

bash
PATCH https://www.googleapis.com/calendar/v3/calendars/{calendarId}/events/{eventId} Authorization: Bearer {access_token}

Request Body:

json
{ "summary": "Updated Team Meeting" }

✅ Step 6: Frontend User Interface

You build the UI:

  • A calendar view (optional): Use FullCalendar.js or similar to show events.
  • Forms for creating/editing events:
    • User fills out event info (title, description, date/time)
    • Submits the form
    • Your backend uses the access token to call the Google Calendar API

✅ Step 7: Store Tokens (Optional)

  • Access tokens expire quickly (usually 1 hour).
  • You can also get a refresh token (when user authorizes) to request new access tokens without requiring the user to log in again.
  • Store tokens securely (e.g., encrypted in your database).

✅ Step 8: Display Events on Your Website

  • You can GET events from Google Calendar and display them in:
    • A list
    • A calendar (using FullCalendar.js, Bootstrap Calendar, etc.)

Example: GET events

bash
GET https://www.googleapis.com/calendar/v3/calendars/{calendarId}/events Authorization: Bearer {access_token}

✅ What You’ll Need (Tech Stack Suggestions)

  • Frontend: Bootstrap 5 forms, optional FullCalendar.js for visual calendars.
  • Backend: Node.js / Express, Django / Flask (Python), PHP, or whatever you prefer.
  • OAuth 2.0 libraries:
    • Node.js: googleapis npm package
    • Python: google-auth and google-api-python-client
    • PHP: Google API PHP Client

✅ User Workflow (From Jack’s Perspective)

  1. Jack logs into Website A.
  2. Clicks “Connect Google Calendar” (OAuth flow starts).
  3. Jack authorizes access ➜ redirected back.
  4. Jack can now add/edit/delete events directly on Website A.
  5. Jack’s changes sync instantly with Google Calendar.

✅ Security Tips

  • Only request the scopes you need.
  • Use HTTPS everywhere.
  • Securely store tokens (never expose on the frontend).
  • Regularly review API quotas and logs for anomalies.

✅ Optional: Embed Google Calendar View

Even after all this, you can embed a view-only Google Calendar if needed, but the power is in creating your own interface for interaction.

✅ Want to See Example Code?

I can walk you through an example in:

  • Node.js
  • Python (Flask/Django)
  • PHP Let me know which backend you’re using, and we’ll build out real working code!
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