calendarmod

Table of Contents

1. Overview
   1. Version Update
2. Getting started
3. Usage
   1. Subscribe User to a Calendar in Go Project
   2. Subscribe Group to a Calendar in Go Project
4. Functions
   1. SetUpSVAAuth
   2. SubscribeUserToCalendar
5. Google Cloud API
   1. Set up Google Cloud API Access
6. Common Questions
7. Troubleshoot
8. Support
   

Overview

calendarmod is a Go Package designed to facilitate Google Calendar services for Rutgers University. This module includes the following core functionality:

1. Authenticate Client for Google API using a service account
2. Subscirbe user to a dynamic Google calendar
3. Subscirbe a group of users to a dynamic Google calendar

Version Update

Make sure you are using one of the stable version. Update to the newest minor version.

• v0.1.18: Stable version
  1. Add unsubscription features for individual user and group
• v0.1.15: Stable version

Getting started

Prerequisite

• Obtain a Google Service Account Key json file and enable the necessary Google API permissions for the Google Service Account.
  • For detailed instructions, refer to the section Set up Google Cloud API Access.
• Set up a Go project to utilize this package.

Installation

1. move to the directory of your Go Project in the terminal
2. run the command

   go get github.com/oss/calendarmod
   

Usage

Subscribe User to a Calendar in Go Project

1. Import the package

   import (
       "github.com/oss/calendarmod"
   )
   

2. Create a authentification client based on the service account

   client := calendarmod.SetUpSVAClient(serviceAccountJSON, true)
   

3. Subscribe the user to the calendars

   success := client.SubscribeUserToCalendar(calendarid, userEmail)
   

Subscribe Group to a Calendar in Go Project

1. Import the package

   import (
       "github.com/oss/calendarmod"
   )
   

2. Create a authentification client based on the service account

   client := calendarmod.SetUpSVAClient(serviceAccountJSON, true)
   

3. Subscribe the user to the calendars

   success := client.SubscribeGroupToCalendar(calendarid, userlist)
   

Functions

func SetUpSVAClient

func SetUpSVAClient(serviceAccountJSON []byte, useCalendar bool) *CalendarClient

SetUpSVAClient initialize authentification client with service account and returns CalendarClient with context and config.

• useCalendar should always to be set to true to use Calendar services.
• To authentificate, make sure to set up all necessary permissions for the Google Service account.

Exp:

// set up Service Account authentification client
serviceAccountJSON, err := os.ReadFile("SERVICE_ACCOUNT_PATH")
if err != nil {
	log.Fatalf("Could not read service account credentials file, %s => {%s}", sap, err)
}

auth := calendarmod.SetUpSVAAuth(serviceAccountJSON, true)

func SubscribeUserToCalendar

func (c *CalendarClient) SubscribeUserToCalendar(user string, calendarid string) bool 

SubscribeUserToCalendar subscribes user to a dynamic Google Calendar. Call the function with the Calendar Client created from func SetUpSVAClient

• user must be a a valid google email address under the same domain of the Service Account client.
• calendarID can be retrived from Google Calendar => Calendar settings.

Exp:

calendarID:= "c_d3e80545746779e9e3957248314356fe4d9e1dcc27c2259b8c029ad5ee6f9cdf@group.calendar.google.com"
userEmail:= "[email protected]"
success := calendarmod.SubscribeUserToCalendar(calendarID, userEmail)

func UnsubscribeUserFromCalendar

func (c *CalendarClient) UnsubscribeUserFromCalendar(user string, calendarid string) bool 

UnsubscribeUserFromCalendar unsubscribes user from a dynamic Google Calendar. Call the function with the Calendar Client created from func SetUpSVAClient.

If a user is not subscribed to the calendar in the first place, no operation would be done and the function would return true.

• user must be a a valid google email address under the same domain of the Service Account client.
• calendarID can be retrived from Google Calendar => Calendar settings.

Exp:

calendarID:= "c_d3e80545746779e9e3957248314356fe4d9e1dcc27c2259b8c029ad5ee6f9cdf@group.calendar.google.com"
userEmail:= "[email protected]"
success := calendarmod.UnsubscribeUserFromCalendar(calendarID, userEmail)

func SubscribeGroupToCalendar

func (c *CalendarClient) SubscribeGroupToCalendar(calendarID string, userlist []string) bool

SubscribeUserToCalendar subscribes a groups of users to a dynamic Google Calendar. Call the function with the Calendar Client created from func SetUpSVAClient.

This function produces two lists of user cases documenting the outcomes of user calendar subscription attempts.

1. A list of successful subscription cases
2. A list of failed subscription attempts

• calendarID can be retrived from Google Calendar => Calendar settings.
• userlist is list of valid Google emails of targeted users, should be in email format

Exp:

userlist:= ["[email protected]", "[email protected]", "[email protected]"]
calendarID:= "c_d3e80545746779e9e3957248314356fe4d9e1dcc27c2259b8c029ad5ee6f9cdf@group.calendar.google.com"
result := calendarClient.SubscribeGroupToCalendar(calendarID, userlist)

func UnsubscribeGroupFromCalendar

func (c *CalendarClient) UnsubscribeGroupFromCalendar(calendarID string, userlist []string) bool

UnsubscribeGroupFromCalendar unsubscribes a groups of users from a dynamic Google Calendar. Call the function with the Calendar Client created from func SetUpSVAClient.

If a user is not subscribed to the calendar in the first place, no operation would be done and the user would be added to successful user list.

This function produces two lists of user cases documenting the outcomes of user calendar subscription attempts.

1. A list of successful unsubscription cases
2. A list of failed unsubscription attempts

• calendarID can be retrived from Google Calendar => Calendar settings.
• userlist is list of valid Google emails of targeted users, should be in email format

Exp:

userlist:= ["[email protected]", "[email protected]", "[email protected]"]
calendarID:= "c_d3e80545746779e9e3957248314356fe4d9e1dcc27c2259b8c029ad5ee6f9cdf@group.calendar.google.com"
result := calendarClient.UnsubscribeGroupFromCalendar(calendarID, userlist)

Google Cloud API

Set up Google Cloud API Access

1. Log in to Google Cloud Console Google Cloud Console
2. Select the corresponding Google Cloud Project
   1. If the project isn't created yet, Click New Project to create one.
   2. Project existed but doesn't show up.
      1. Search it in the search bar
      2. Couldn't find it. Refer to Google Cloud API Common Question
3. Open the console left side menu => APIs & Services => Enable APIs & Services
4. Enable required API
   • Google Calender API (scope: https://www.googleapis.com/auth/calendar)s
5. Open the console left side menu => IAM & Admin => Service accounts
6. Select the corresponding Service Account
   • If the Service Account isn't created yet, Click + create a service account to create one.
   • For service account: Choose the role Project > owner.
7. Delegating domain-wide authority to the service account
   • For OAuth scopes, enter: ttps://www.googleapis.com/auth/calendar
8. Click into the service account => KEYS => Add KEY => Create new key
9. Create private key for "calendar service test", choose "JSON" for key type
   • Save the JSON file in the projecr directory for authentification to the Service Account.

Common Questions

About Google Cloud API

• Q: Admin has created the project but I couldn't find it in my console.

  A: Check your access role to the project. Make sure you are a owner. If need to change access role, refer to Manage project members or change project ownership

Troubleshoot

• Error: Subscription: Authentification passed, couldn't fetch token

  Authentification sets up
  Subscribe User To Calendar...
  Calendar ID: c_b14ec2724ff6a0cac6558c74bebb0e8b986b4084cf059c68bb2d5b9b070d71ed@group.calendar.google.com
  user: [email protected]
  Post "https://www.googleapis.com/calendar/v3/users/me/calendarList?alt=json&prettyPrint=false": oauth2: cannot fetch token: 401 Unauthorized
  Response: {
  "error": "unauthorized_client",
  "error_description": "Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested."
  }
  panic: Post "https://www.googleapis.com/calendar/v3/users/me/calendarList?alt=json&prettyPrint=false": oauth2: cannot fetch token: 401 Unauthorized
  Response: {
  "error": "unauthorized_client",
  "error_description": "Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested."
  }
  

  Solution:
  

  1. Make sure to enable all APIs included in the scope.
     Check access to "calendarservices.SetUpSVAAuth()", make sure all required scope has enabled
     To enable API: Open the console left side menu => APIs & Services => Enable APIs & Services
     

Support

For assistance, please contact us at [email protected].

Last updated by Seoli Kim on July 23, 2024.