Simple utility to chat directly with a person via Microsoft Teams given their email address, without need to manually search for that particular individual in the application.

chatwith.php

<?php
// Usage:
// https://mysite.xyz/chatwith.php?person=ME@MYSITE.XYZ
//
// Logging:
// Saved as ../chatwith_log/YYYY-MM.csv
// Write permissions required for web server.
//
// Reference:
// https://www.msoutlook.info/question/teams-chat-link-in-email-signature
// https://teams.microsoft.com/l/chat/0/0?users=<youremailaddress>

function isValidEmail($email) {
  if(preg_match('/^[a-z0-9._%+-]+@(MYSITE\.XYZ)$/i', $email)) { 
    // ** 
    // ** IMPORTANT: Change "MYSITE\.XYZ", above, to your own email domain.
    // **
    return true;
  }
  return false;
}

$person = (array_key_exists('person', $_GET) ? trim(urldecode($_GET['person'])) : false);

$loginfo = array(
  date('Y-m-d H:i:s'),
  $person,
  $_SERVER['HTTP_HOST'],
  $_SERVER['REQUEST_URI'],
  $_SERVER['HTTP_REFERER'],
  $_SERVER['REMOTE_ADDR'],
  $_SERVER['HTTP_USER_AGENT']
);

$fp = fopen('../chatwith_log/' . date('Y-m') . '.csv', 'a');
fputcsv($fp, $loginfo);
fclose($fp);

if(!isValidEmail($person)) {
  die('Usage: https://' . $_SERVER['HTTP_HOST'] . $_SERVER['SCRIPT_NAME'] . '?person=&lt;firstname.lastname@acadiau.ca&gt;');
}

header('Location: https://teams.microsoft.com/l/chat/0/0?users=' . $person);
exit();

?>