We now have a sensor and an actuator that speaks HTTP. To tie these together, we also need to add HTTP to the controller. The controller will act as an HTTP client, as opposed to our previous examples where each application acted as an HTTP server. We will use the HttpSocketClient class to access the web resources provided by the sensor. We will create our connection to our sensor, as follows:
HttpSocketClient HttpClient;
HttpClient = new HttpSocketClient ("192.168.0.29", 80, new DigestAuthentication ("Peter", "Waher"));
HttpClient.ReceiveTimeout = 30000;
HttpClient.Open ();Here, we will add the client-side version of the digest authentication scheme found in Clayster.Library.Internet.HTTP.ClientCredentials. We will also specify a timeout of 30,000 milliseconds since we will use the even subscription mechanism of retrieving data from the sensor.
To get data from the sensor is easy. All that is needed to do is get the XML using the GET method and call the...