Mastering Internet of Things

Publishing event-based observable data

Similarly, we add a resource for our motion detector. But for this resource, we will use the acknowledged service, since missing a value when expecting one might have serious consequences:

this.motionResource = this.coapEndpoint.Register("/Motion", 
   (req, resp) => 
   { 
         string s; 
 
         if (this.lastMotion.HasValue) 
               s = this.lastMotion.Value ? "true" : "false"; 
               else 
               s = "-"; 
 
         resp.Respond(CoapCode.Content, s, 64); 
   }, Notifications.Acknowledged, "Motion detector.", null, null, 
   new int[] { PlainText.ContentFormatCode }); 

We will use this resource to illustrate event-based observable data. When the motion detector changes value, we don't want a delay in the sending of the new value to any subscribers, as we want the ...