Automatic Calendar Availability – 2024 Efficiency Boost

<#
 This script sets default calendar permissions for all users in an Office 365 environment to a given value.

 Reviewer: FolderVisible, ReadItems
 AvailabilityOnly: View only availability data
 LimitedDetails: View availability data with subject and location

 2017.10.30 - Simon Skotheimsvik

 https://docs.microsoft.com/en-us/powershell/module/exchange/set-mailboxfolderpermission?view=exchange-ps

 Find format: (Get-MailboxFolderStatistics <username> -FolderScope Calendar).Identity
#>

# Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline

# Generate a list of all mailboxes
$users = Get-Mailbox -ResultSize Unlimited

# Set default access to Reviewer for all mailboxes
foreach ($user in $users) {
    Write-Host -ForegroundColor Green "User in focus: $($user.UserPrincipalName)"
    
    # Set variable for English Calendar
    $IdentityCal = "$($user.Alias):\Calendar"
    $error.Clear()

    Get-MailboxFolderPermission -Identity $IdentityCal -ErrorAction SilentlyContinue
    if ($error[0]) {
        Write-Host -ForegroundColor Cyan "Can't find Calendar - checking Kalender"
        # Set variable for Norwegian Calendar
        $IdentityCal = "$($user.Alias):\Kalender"
    }

    Write-Host -ForegroundColor Green "Setting permission for $IdentityCal"
    Set-MailboxFolderPermission -Identity $IdentityCal -User Default -AccessRights LimitedDetails
}

<#
    .SYNOPSIS
    Created on:     19.02.2024
    Created by:     CloudWay, Simon Skotheimsvik
    Info:           Entra Role Assignments
    
    .DESCRIPTION
    Routine to add necessary roles to System Assigned Managed Identity in Function App or Automation Account.
#>

# Install-Module Microsoft.Graph -Scope CurrentUser
Import-Module Microsoft.Graph.Applications

# Variables
$TenantID = "YOUR VALUE HERE"
$managedIdentityId = "YOUR VALUE HERE"
$roleNames = "User.Read.All","Calendars.ReadWrite"

# Connect to Graph
Connect-MgGraph -Scopes Application.Read.All, AppRoleAssignment.ReadWrite.All, RoleManagement.ReadWrite.Directory -TenantId $TenantID

# Get the Microsoft Graph Service Principal
$msgraph = Get-MgServicePrincipal -Filter "AppId eq '00000003-0000-0000-c000-000000000000'"

# Set the app role assignments
foreach ($roleName in $roleNames) {
    write-host $roleName
    $role = $Msgraph.AppRoles| Where-Object {$_.Value -eq $roleName} 
    New-MgServicePrincipalAppRoleAssignment -ServicePrincipalId $managedIdentityId -PrincipalId $managedIdentityId -ResourceId $msgraph.Id -AppRoleId $role.Id
}
 
Disconnect-MgGraph

<#
    .SYNOPSIS
    Name: RUNBOOK-SetExchangeCalendarPermissions.ps1
    Author: Alexander Holmeset, https://alexholmeset.blog, https://x.com/AlexHolmeset
    Contributor: Simon Skotheimsvik, http://skotheimsvik.no, https://x.com/SSkotheimsvik
    Instructions: https://alexholmeset.blog/2024/06/11/set-default-calendar-permission-for-your-organization-with-graph-api/
    Versions:   1.0 - 2017.10.30 - Simon Skotheimsvik, initial version using ExchangeOnline module
                1.1 - 2024.06.12 - Alexander Holmeset, updated to use Microsoft Graph PowerShell SDK
                1.2 - 2024.06.13 - Simon Skotheimsvik, tuned the script more towards Azure Automation.

    .DESCRIPTION
    This script sets the default calendar permissions for all users in a Microsoft 365 organization to LimitedRead.
#>

# Set the permission level to be set on the calendars.
# Options can be found here: https://learn.microsoft.com/en-us/graph/api/resources/calendarpermission?view=graph-rest-1.0#calendarroletype-values
$Permission = "LimitedRead"
  
# Connects to Microsoft Graph with the specified scopes  
Connect-MgGraph -Identity
  
# Generates a list of all licensed users in the Microsoft 365 organization with a mailbox
$users = Get-MgUser -All -Property "id", "AssignedLicenses", "UserPrincipalName", "Mail" | Where-Object { $_.AssignedLicenses.Count -gt 0 -and $_.Mail -ne $null}
#$users = Get-MgUser -All -Property "id", "AssignedLicenses", "UserPrincipalName", "Mail" | Where-Object { $_.AssignedLicenses.Count -gt 0 -and $_.Mail -ne $null -and $_.UserPrincipalName -eq "simon.skotheimsvik@domain.com"}

# Sets default access to LimitedRead for all calendars in each user's mailbox  
foreach ($user in $users) {   
  
    # Prints the user currently in focus
    Write-Output "User in focus = $($user.userprincipalname)"   
  
    # Initializes the variables to store calendar permissions  
    $CalenderPermissions = @()  
    $CalenderPermissions = Get-MgUserCalendarPermission -UserId $user.id 
  
    # If the user has any calendar permissions, update them  
    if ($CalenderPermissions) {  
        $CalenderPermissionsMyOrg = @()  
        $CalenderPermissionsMyOrg = $CalenderPermissions | Where-Object { $_.EmailAddress.Name -eq "My Organization" }  
  
        # Updates the calendar permissions for the user  
        if ($CalenderPermissionsMyOrg.Role -ne $Permission) {
            Write-Warning "- Changing MyOrg-permission on calendar for $($user.userprincipalname) from $($CalenderPermissionsMyOrg.Role) to $($Permission)."   
            Update-MgUserCalendarPermission -UserId $user.id -Role $Permission -CalendarPermissionId $CalenderPermissionsMyOrg.id
        }  
        # If the permission is already set, print a message
        else {  
            Write-Output "- MyOrg-permission already set to $($Permission) on calendar for $($user.userprincipalname)."  
        }
    }  
}