pjs11@R5124614 email_filter $ more ./imap_ad_clientcreds_test.pl
#!/usr/bin/env perl

use strict;
use utf8;
use URI::Escape;
use MIME::Base64;
use Mail::IMAPClient;
use Azure::AD::ClientCredentialsV2;

our $app_id = '**** MY APP ID ****';
our $secrets_id = '**** MY SECRET ID ****';
our $secrets_value  = '**** MY SECRET VALUE ****';
our $tenant = '**** MY TENANT ID ****';

my $imapserver="outlook.office365.com";
my $username='tivolialertsdev@mayo.edu';

my $creds = Azure::AD::ClientCredentialsV2->new(
    resource_id => 'https://graph.windows.net/',
    client_id => $app_id,
    secret_id => $secrets_value,
    tenant_id => $tenant,
    scope => '.default',
    );
my $oauth_token = $creds->access_token;
print "Received token: $oauth_token\n";

my $oauth_sign = encode_base64("user=". $username ."\x01auth=Bearer ". $oauth_token ."\x01\x01", '');
# detail: https://developers.google.com/google-apps/gmail/xoauth2_protocol
print "Encoded: $oauth_sign\n";

my $imap = Mail::IMAPClient->new(
    Server              => $imapserver,
    Port                => 993,
    Ssl                 => 1,
    Uid                 => 1,
    IgnoreSizeErrors    => 1,
    Debug               => 1,
    ) or die('Can\'t connect to imap server.');
$imap->Showcredentials(1);  # Massive debugging, please
$imap->authenticate('XOAUTH2', sub { return $oauth_sign }) or
    die("Auth error: ". $imap->LastError);