title: Subscribes to a listener service of outlook for receive a notifications when calendar events change in Outlook.com
body: <p>I need to subscribe to Outlook Calendar notifications for getting changes to Outlook on my server.  I've <a href="https://msdn.microsoft.com/office/office365/api/notify-rest-operations#NotificationResource" rel="nofollow noreferrer">read the documentation</a> and my code is mostly working fine but I'm stuck with the listener.</p>
  
  <p>For notifications I</p>
  
  <ul>
  <li>First, create subscription</li>
  <li>On success, it'll return me a subscription id with other information</li>
  <li>After that when I made any changes in the calendar, it'll ping on my notification URL. BUT it doesn't give me which data was changed, it only gives me the following:</li>
  </ul>
  
  <pre><code>{
    "USER": "devapi",
    "HOME": "/home/devapi",
    "FCGI_ROLE": "RESPONDER",
    "QUERY_STRING": "",
    "REQUEST_METHOD": "POST",
    "CONTENT_TYPE": "application/json; charset=utf-8",
    "CONTENT_LENGTH": "1156",
    "SCRIPT_NAME": "/notification.php",
    "REQUEST_URI": "/notification.php",
    "DOCUMENT_URI": "/notification.php",
    "DOCUMENT_ROOT": "/home/ubuntu/www/devapi/api/web",
    "SERVER_PROTOCOL": "HTTP/1.1",
    "REQUEST_SCHEME": "https",
    "HTTPS": "on",
    "GATEWAY_INTERFACE": "CGI/1.1",
    "SERVER_SOFTWARE": "nginx/1.9.9",
    "REMOTE_ADDR": "000.000.00.000",
    "REMOTE_PORT": "62530",
    "SERVER_ADDR": "000.00.0.000",
    "SERVER_PORT": "443",
    "SERVER_NAME": "devapi.test.com",
    "REDIRECT_STATUS": "200",
    "SCRIPT_FILENAME": "/home/ubuntu/www/devapi/api/web/notification.php",
    "HTTP_CONTENT_TYPE": "application/json; charset=utf-8",
    "HTTP_ACCEPT": "text/xml",
    "HTTP_CLIENTSTATE": "OutlookPush-56dfcd91df29c",
    "HTTP_HOST": "devapi.test.com",
    "HTTP_ODATA_VERSION": "4.0",
    "HTTP_CONTENT_LENGTH": "1156",
    "HTTP_CONNECTION": "Close",
    "PHP_SELF": "/notification.php",
    "REQUEST_TIME_FLOAT": 1457516659.3082,
    "REQUEST_TIME": 1457516659
  }
  </code></pre>