It has been a while since I blogged the SMS API published by Telstra (you can find it here). After that post I spent quite a long time to blog other stuff. Recently I re-visited Telstra's Dev centre and found this interesting WiFi API. So let's try this API today.
Basically the API will accept query parameters of latitude, longitude, and a radius, then it will give us a list of available Telstra WiFi hotspots around the coordination.
The first step to use this API is to get the API key. Similar to the steps I described in my SMS post, it should be quite simple to get a new app created. Just be aware, the product to be ticked is WiFi API, as demonstrated below.
After the registration, expand the app pannel by pressing its name, you should see the consumer key and consumer secret are available now.
Time to look at C# implementation of the API.
Create a Winform project in Visual Studio, and I have a form created: 3 textboxes to accept latitude, longitude, and radius. A calculate button to call the WiFi API, and finally a list box to display all returned WiFi hotspots' addresses (keep in mind that, at this stage the API will return maximum 10 hot spots).
Before starting of the code task, I added two references into my project: one is System.Net.Http, which will be used to issue request and receive response; another one has been heavily used in my previous posts: Newtonsoft.Json. It will help us parse the json string returned from API call.
One thing we can reuse from previous SMS post is the authentication method: pass in consumer key and consumer secret, and then return a token and its expiry seconds:
private async Task<TelstraToken> GetAccessToken(string consumerkey, string consumersecret)
{
TelstraToken Token = new TelstraToken();
string AccessUrl = @"https://api.telstra.com/v1/oauth/token";
HttpClient authClient = new HttpClient();
HttpContent httpContent = new FormUrlEncodedContent(new Dictionary<string, string>
{
{"client_id", consumerkey},
{"client_secret", consumersecret},
{"grant_type", "client_credentials"},
{"scope", "WIFI"}
});
HttpRequestMessage Request = new HttpRequestMessage()
{
Method = HttpMethod.Post,
RequestUri = new Uri(AccessUrl),
Content = httpContent
};
try
{
var ResponseMessage = await authClient.SendAsync(Request);
var Response = await ResponseMessage.Content.ReadAsStringAsync();
if (ResponseMessage.IsSuccessStatusCode)
{
var AuthToken = JsonConvert.DeserializeObject<object>(Response);
JObject jObj = JObject.Parse(AuthToken.ToString());
Token.AccessToken = jObj["access_token"].ToString();
Token.ExpiredDt = DateTime.Now.AddSeconds(double.Parse(jObj["expires_in"].ToString()));
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
return Token;
}
You may question the TelstraToken object from the method above: It is just a simple object to host token value/expiry date time. Beside this simple object, I also created another helper class for Hotspot returned from API. Below are the definitions for these two classes:
internal class TelstraToken
{
internal string AccessToken;
internal DateTime ExpiredDt;
internal TelstraToken() { }
internal TelstraToken(string _accessToken, DateTime _expiredDt)
{
this.AccessToken = _accessToken;
this.ExpiredDt = _expiredDt;
}
}
internal class TelstraWifiHotSpot
{
internal string latitude;
internal string longitude;
internal string address;
internal string city;
internal string state;
internal TelstraWifiHotSpot(string _latitude, string _longitude, string _address, string _city, string _state)
{
this.latitude = _latitude;
this.longitude = _longitude;
this.address = _address;
this.city = _city;
this.state = _state;
}
public override string ToString()
{
string fullAddress = string.IsNullOrWhiteSpace(address) ? string.Empty : address;
fullAddress += ", ";
fullAddress += string.IsNullOrWhiteSpace(city) ? string.Empty : city;
fullAddress += " ";
fullAddress += string.IsNullOrWhiteSpace(state) ? string.Empty : state;
return fullAddress;
}
}
Now all preparations are done. The only missing part is the button click event:
private async void btnCalculate_Click(object sender, EventArgs e)
{
List<TelstraWifiHotSpot> lst = new List<TelstraWifiHotSpot>();
if (_token == null || _token.ExpiredDt < DateTime.Now)
{
_token = await GetAccessToken("your consumer key", "your consumer secret");
}
string latitude = txtLatitude.Text;
string longitude = txtLongitude.Text;
string radius = txtRadius.Text;
string url = string.Format("https://api.telstra.com/v1/wifi/hotspots?lat={0}&long={1}&radius={2}", latitude, longitude, radius);
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _token.AccessToken);
HttpRequestMessage request = new HttpRequestMessage()
{
Method = HttpMethod.Get,
RequestUri = new Uri(url)
};
HttpResponseMessage responseMessage = await client.SendAsync(request);
var message = await responseMessage.Content.ReadAsStringAsync();
var jMsg = JsonConvert.DeserializeObject<object>(message);
foreach (var j in (JArray)jMsg)
{
string wifiLatitude = ((JObject)j)["lat"].ToString();
string wifiLongitude = ((JObject)j)["long"].ToString();
string wifiAddress = ((JObject)j)["address"].ToString();
string wifiCity = ((JObject)j)["city"].ToString();
string wifiState = ((JObject)j)["state"].ToString();
TelstraWifiHotSpot hotspot = new TelstraWifiHotSpot(wifiLatitude, wifiLongitude, wifiAddress, wifiCity, wifiState);
lst.Add(hotspot);
}
if (lst.Count > 0)
{
lstHotspots.DataSource = lst;
lstHotspots.DisplayMember = lst.ToString();
}
}
After we put everything together and run the project, you should be able to find the hotspots Telstra provided:
