I need not explain about the remote work situation now. At home my family has somehow adjusted to this remote working. Like everyone I use a shared room as home office and lock it during office time for some focused work. When someone wants to access the room, they knock the door. If I am free then I open the door or else I don’t open the door. My family members never know when I am in meeting and when I am free. Only way to find out is knock the door. At times I get irritated by this interruption. One day my spouse mentioned, why don’t you put light outside your door about your status.
There is a saying when a software engineer gives an estimate, it is always an under estimation. Because sometimes a simple thing becomes really complicated. I too did something similar. let me tell you the story. To start with, my mental solution ran something like this
- Teams should expose some kind of automation API.
- Use the API and fetch the status information.
- Based on the status, update a led connected to Nodemcu IOT device.
And I estimated to finish this during Friday evening.
Teams Status is part of MS Graph API
After some search I found the “Status” information is part of Graph API. And Presence information is in beta state as of now. I gave a try in the Graph Explorer
https://graph.microsoft.com/beta/me/presence
And I received the response as
{
"@odata.context": "https://graph.microsoft.com/beta/$metadata#users('<user id guid>')/presence/$entity",
"id": "<user id guid>",
"availability": "Busy",
"activity": "InACall",
"outOfOfficeSettings":
{
"message": null,
"isOutOfOffice": false
}
}
I was happy to see the information available in the reply JSON. Now all that I need to do, is to poll this api and update my status led.
Push vs Poll status information
I felt a bit bad about polling the status information, since I have to decide on a frequency. If I need the update very fast(near real time) I need to poll frequently and on the other hand if I don’t want to bombard the polling API endpoint (or even get blocked by the Graph API endpoint) I should reduce the frequency. My developer spider sense told me that there should be some kind of push notification for this information. As expected Graph API provided a pub-sub model change notification for this case. I can add a subscription using this endpoint
https://graph.microsoft.com/v1.0/subscriptions
and POST a message in JSON format
{
"changeType": "updated",
"notificationUrl": "https://<mywebapi>.azurewebsites.net/api/TeamStatusHook",
"resource": "/communications/presences/<user id guid>",
"expirationDateTime": "2021-08-13T22:00:00.0Z",
"clientState": "FeroseStatusUpdate",
"latestSupportedTlsVersion": "v1_2"
}
and received the successful subscription for an hour(for some reason they give the subscription only for an hour always) as below.
{
"@odata.context": "https://graph.microsoft.com/v1.0/$metadata#subscriptions/$entity",
"id": "22fdb7f7-15ce-4568-b3fb-47e0aaa8db28",
"resource": "/communications/presences/<user id guid>",
"applicationId": "de8bc8b5-d9f9-48b1-a8ad-b748da725064",
"changeType": "updated",
"clientState": "FeroseStatusUpdate",
"notificationUrl": "https://<mywebapi>.azurewebsites.net/api/TeamStatusHook",
"notificationQueryOptions": null,
"lifecycleNotificationUrl": null,
"expirationDateTime": "2021-08-16T06:36:02.1704178Z",
"creatorId": "<user id guid>",
"includeResourceData": null,
"latestSupportedTlsVersion": "v1_2",
"encryptionCertificate": null,
"encryptionCertificateId": null,
"notificationUrlAppId": null
}
Setting up the Call back URL
In the above subscription you can see I gave
https://<mywebapi>.azurewebsites.net/api/TeamStatusHook
as the call back URL. As per the documentation this end point should be capable of responding to two kind of requests.
- Graph system shall send POST with a validation token as query parameter and content type text/plain. the end point shall respond within 10 secs
- The end point shall return the token as a body,
- Content type as text/plain
- HTTP 200 OK.
- Graph system shall send the real update as below. And the end point shall respond with a 201 Accepted.
{
"value":
[
{
"subscriptionId":"e96cf426-e71a-47b5-9a48-52b17a3e3b27",
"clientState":"FeroseStatusUpdate",
"changeType":"updated",
"resource":"communications/presences('<user id guid>')",
"subscriptionExpirationDateTime":"2021-08-13T06:06:58.660307-07:00",
"resourceData":
{
"@odata.type":"#Microsoft.Graph.presence",
"@odata.id":"communications/presences('<user id guid>')",
"id":"<user id guid>",
"activity":"Busy",
"availability":"Busy"
},
"tenantId":"<tenant id guid>"
}
]
}
I thought of setting up an Azure Function, but I have to store the update for my IOT device queries. Setting up a stateful Azure Function was a bit complicated, so I went with a ASP.Net core web api app. As a shortcut I stored the status in a static variable of web api controller.
[Route("api/[controller]")]
[ApiController]
public class TeamStatusHookController : ControllerBase
{
static string currentStatus = "{\"Status\":\"Unknown\"}";
[HttpPost]
public IActionResult UpdateStatus()
{
var contentType = HttpContext.Request.Headers["Content-Type"];
if (contentType.ToString().Contains("text/plain"))
{
var validationToken = HttpContext.Request.Query["validationToken"].ToString();
return Content(validationToken);
}
if (contentType.ToString().Contains("application/json"))
{
using (StreamReader reader = new StreamReader(Request.Body, Encoding.UTF8))
{
var jsonData = JsonDocument.Parse(reader.ReadToEndAsync().Result);
var activity = jsonData.RootElement.GetProperty("value")[0].GetProperty("resourceData").GetProperty("activity");
var availability = jsonData.RootElement.GetProperty("value")[0].GetProperty("resourceData").GetProperty("availability");
currentStatus = $"{{\"availability\":\"{availability}\",\"activity\":\"{activity}\"}}";
}
return Accepted();
}
return NotFound();
}
[HttpGet]
public JsonResult GetStatus()
{
return new JsonResult(currentStatus);
}
It worked and I can see my status information in the GetStatus endpoint.
Connecting the IOT device
The final step was to connect the information to the IOT device. I had a nodemcu (programmable ESP8266) lying around with an in built led. I connected this to the status check api. I polled every 5 seconds (to see how things work).
#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClientSecureBearSSL.h>
/* Set these to your desired credentials. */
const char *ssid = "<ssid>"; //Enter your WIFI ssid
const char *password = "<passwd>"; //Enter your WIFI password
ESP8266WiFiMulti WiFiMulti;
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(115200);
Serial.println();
Serial.println();
Serial.println();
for (uint8_t t = 4; t > 0; t--) {
Serial.printf("[SETUP] WAIT %d...\n", t);
Serial.flush();
delay(1000);
}
WiFi.mode(WIFI_STA);
WiFiMulti.addAP(ssid, password);
}
void loop() {
// wait for WiFi connection
if ((WiFiMulti.run() == WL_CONNECTED)) {
std::unique_ptr<BearSSL::WiFiClientSecure>client(new BearSSL::WiFiClientSecure);
//client->setFingerprint(fingerprint);
// for now disable https certificate check:
client->setInsecure();
HTTPClient https;
Serial.print("[HTTPS] begin...\n");
if (https.begin(*client, "https://<mywebapi>.azurewebsites.net/api/TeamStatusHook")){
// HTTPS
Serial.print("[HTTPS] GET...\n");
// start connection and send HTTP header
int httpCode = https.GET();
// httpCode will be negative on error
if (httpCode > 0) {
// HTTP header has been send and Server response header has been handled
Serial.printf("[HTTPS] GET... code: %d\n", httpCode);
// file found at server
if (httpCode == HTTP_CODE_OK || httpCode == HTTP_CODE_MOVED_PERMANENTLY) {
String payload = https.getString();
if(payload.indexOf("Busy")>0 || payload.indexOf("DoNotDisturb")>0){
digitalWrite(LED_BUILTIN, 0);
}else{
digitalWrite(LED_BUILTIN, 1);
}
Serial.println(payload);
}
} else {
Serial.printf("[HTTPS] GET... failed, error: %s\n", https.errorToString(httpCode).c_str());
}
https.end();
} else {
Serial.printf("[HTTPS] Unable to connect\n");
}
}
Serial.println("Wait 5s before next round...");
delay(5000);
}
Again things worked fine. I can see the status led light up when I am busy. Now it is time to move this solution to production and sustain.
Move the application to production
First step is to subscribe for this change notification from the web app. And I need an access token to invoke the endpoint. To get an access token you need a client id and client secret. And for that you need app registered in Azure AD. I tried registering the app, unfortunately the app registration is blocked by office 365 admin for security reason. I panicked a bit. ok let me try it in my other azure subscription, the app registration went through this time without any issue, but I cannot add a subscription for my teams tenant from this app (basically the app has to be approved by the teams admin again). I tried using power automate for the subscription. But invoking a REST API is premium and not available to me under the free plan. Slowly my options ran out one by one. The only option left was to create/update the subscription manually in the graph explorer. This is not a viable option for me. And I can sense the failure here.
You don’t own your data
Until now when I did something with an VBA office automation (Word/Excel), I owned the data in my machine or easily can access it. Now MS Teams being a cloud app, the teams status updates beautifully in the desktop app, web site, iPhone app and android tablet but not in my toy app. I realized that I don’t own my teams data anymore. Or I own the data, but cannot easily access that with my own toy app anymore. I need the app cleared by office 365 admin.
I wrote this down so that someone who has access to the final step can setup a IOT status led.
Update: Corrected some code that was corrupted by wordpress editor last time.
Ferose Blog 