Graph API – Pull a list of Folders for a Mailbox via PowerShell

Scenario – You need to pull a list of folders in a mailbox.

Prerequisites: You already have the following configured:
–Registered App in Azure: An Azure Registered app to connect to with Application Permissions for Mail.Read, Mail.ReadWrite, Mail.ReadBasic.All, and Mail.Send. (Not all permissions listed may be necessary for the specific function below)
–Bearer Authentication Token: A method for pulling back a bearer token and storing it to pass Authorization into your RestAPI package (See my previous post about get-accesstoken). The get-accesstoken authenticates against your Registered App in Azure.

PowerShell Scriptlets:

#Examples are below for common Folders and how to build the URI
#Notes: For common folders, you can use the name of the folder. For user created folders, or other non-common folders, you can use the Base64 ID

#1. Define $MBX
$mbx = "steve@steveman.com"                


#2. Build your #APPURI
$appuri = "https://graph.microsoft.com/v1.0/users/$mbx/mailfolders"   #to get a list of folders

$appuri = "https://graph.microsoft.com/v1.0/users/$mbx/mailfolders/inbox"   #using common folder names

$appuri = "https://graph.microsoft.com/v1.0/users/$mbx/mailfolders/AAMkADY3ODhkMDNlLTRjM2YtNDJjYi04YTkzLTFmNjFhYTcyMjA2NwAuAAAAAAAM5kRh6DylRZ4XsImGGVClAQA8oulgK3qgQ659gFhlXH_UAAAAAAEMAAA="  #Using Base64 naming for any folder in mailbox


#3. Build  your $RestSplat
$RestSplat = @{
                        URI = $appuri
                        Headers = $(get-accesstoken)
                        Method = 'GET'
                        ContentType = "application/json"
                    }


#4. Run the RestMethod to pull back the Folder(s)
$Folders = Invoke-RestMethod @RestSplat


#5. Display the Results
$Folders.Value



Note: GraphAPI only pulls back 10 items at a time.  If you need to pull back more than 10 items, run the following Do-While Loop:

#To find all Folders in a mailbox, run this:
                #Create your Collection Variable
                    $Folders = @()
                #Build your Starting URI
                    $appuri = "https://graph.microsoft.com/v1.0/users/$mbx/mailfolders"   
                #Run a Do-While Loop
            
                Do{
                    "Running $appUri"
            
                    $RestSplat = @{
                        URI = $appuri
                        Headers = $(get-accesstoken)
                        Method = 'GET'
                        ContentType = "application/json"
                    }
                
                    $Tempresults = Invoke-RestMethod @RestSplat
                    $Folders += $tempresults.value
                    $appuri = $tempresults."@odata.NextLink"
                    }While($appuri -ne $null)

          #Display your Messages
                $Folders