Develop Reference

MqttNet version 4.1.3.563 Basic example

Following this example I have now therefore been required to update the MQTT.NET from version 3 (that works thanks the provided help) to version 4.
A very basic set of capabilities would be enough:
Connect to an adress with a timeout
Check if the connection has gone well
Receive messages
check disconnection
that was extremely easy in version 3
MqttClientOptionsBuilder builder = new MqttClientOptionsBuilder()
.WithClientId("IoApp" + HelperN.MQTT.GetClientID(true))
.WithTcpServer("localhost", 1883);
ManagedMqttClientOptions options = new ManagedMqttClientOptionsBuilder()
.WithAutoReconnectDelay(TimeSpan.FromSeconds(60))
.WithClientOptions(builder.Build())
.Build();
mqttClient = new MqttFactory().CreateManagedMqttClient();
mqttClient.ConnectedHandler = new MqttClientConnectedHandlerDelegate(OnConnected);
mqttClient.DisconnectedHandler = new MqttClientDisconnectedHandlerDelegate(OnDisconnected);
mqttClient.ConnectingFailedHandler = new ConnectingFailedHandlerDelegate(OnConnectingFailed);
mqttClient.SubscribeAsync(...);
mqttClient.SubscribeAsync(...);
mqttClient.StartAsync(options).GetAwaiter().GetResult();
mqttClient.UseApplicationMessageReceivedHandler(args => { OnMessageReceived(args); });
but when it comes to version 4 if I have to relay on those examples I have problems.
Let's start from the connection
public static async Task Connect_Client_Timeout()
{
/*
* This sample creates a simple MQTT client and connects to an invalid broker using a timeout.
*
* This is a modified version of the sample _Connect_Client_! See other sample for more details.
*/
var mqttFactory = new MqttFactory();
strError = String.Empty;
using (var mqttClient = mqttFactory.CreateMqttClient())
{
var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("aaaa127.0.0.1",1883).Build();
try
{
using (var timeoutToken = new CancellationTokenSource(TimeSpan.FromSeconds(5)))
{
await mqttClient.ConnectAsync(mqttClientOptions, timeoutToken.Token);
}
}
catch (OperationCanceledException exc)
{
strError = "Connect_Client_Timeout exc:" + exc.Message;
}
}
}
And I call this task from the main awaiting the result.
var connectTask = Connect_Client_Timeout();
connectTask.Wait();<-----never ends
Since I put a wrong address "aaaa127.0.0.1" I expect a failure after 5 seconds. But the connectTask.Wait never end. But even if I put the right address "127.0.0.1" it never exits.
So perhaps the error stands in the connectTask.Wait();.
Thanks

The solution is here
In short you have to do this:
static async Task Connect()
{
IManagedMqttClient _mqttClient = new MqttFactory().CreateManagedMqttClient();
// Create client options object
MqttClientOptionsBuilder builder = new MqttClientOptionsBuilder()
.WithClientId("behroozbc")
.WithTcpServer("localhost");
ManagedMqttClientOptions options = new ManagedMqttClientOptionsBuilder()
.WithAutoReconnectDelay(TimeSpan.FromSeconds(60))
.WithClientOptions(builder.Build())
.Build();
// Set up handlers
_mqttClient.ConnectedAsync += _mqttClient_ConnectedAsync;
_mqttClient.DisconnectedAsync += _mqttClient_DisconnectedAsync;
_mqttClient.ConnectingFailedAsync += _mqttClient_ConnectingFailedAsync;
// Connect to the broker
await _mqttClient.StartAsync(options);
// Send a new message to the broker every second
while (true)
{
string json = JsonSerializer.Serialize(new { message = "Hi Mqtt", sent = DateTime.UtcNow });
await _mqttClient.EnqueueAsync("behroozbc.ir/topic/json", json);
await Task.Delay(TimeSpan.FromSeconds(1));
}
Task _mqttClient_ConnectedAsync(MqttClientConnectedEventArgs arg)
{
Console.WriteLine("Connected");
return Task.CompletedTask;
};
Task _mqttClient_DisconnectedAsync(MqttClientDisconnectedEventArgs arg)
{
Console.WriteLine("Disconnected");
return Task.CompletedTask;
};
Task _mqttClient_ConnectingFailedAsync(ConnectingFailedEventArgs arg)
{
Console.WriteLine("Connection failed check network or broker!");
return Task.CompletedTask;
}
}
and then just call Connect() and rely on the subscribed examples

Flurl PostUrlEncoded does GET instead of POST

I must be missing something very obvious, but I can't tell what. I have a DoLoginAsync like so:
private async Task DoLoginAsync(bool force = false)
{
try
{
if (client.Cookies.ContainsKey("user_credentials") && !force)
{
return;
}
var html = client.Request("login").GetStringAsync().Result;
var doc = new HtmlDocument();
doc.LoadHtml(html);
var csrf_token = doc.DocumentNode.SelectNodes("//meta[#name='csrf-token']").First().GetAttributeValue("content", string.Empty);
var values = new Dictionary<string, string>
{
{ "user_session[email]", user },
{ "user_session[password]", password },
{ "authenticity_token", csrf_token }
};
var result = await client.Request("user_session").PostUrlEncodedAsync(values);
}
catch (Exception e)
{
}
When I run this code in a test with a breakpoint in the catch clause I get an exception
Call failed with status code 404 (Not Found): GET http://www.whatever.com/user_session
WTF? I'm expecting PostUrlEncodedAsync to do a POST, not a GET. Anybody have an idea why this can happen?
The Flurl client is instantiated as client = new FlurlClient(BASE_URL).EnableCookies();
UPDATE
Tried the following test which fails with the same exception
[TestMethod]
public async Task TheTest()
{
var message = "";
try
{
var client = new FlurlClient("http://www.slimmemeterportal.nl/").EnableCookies();
var html = await client.Request("login").GetStringAsync();
var doc = new HtmlDocument();
doc.LoadHtml(html);
var csrf_token = doc.DocumentNode.SelectNodes("//meta[#name='csrf-token']").First().GetAttributeValue("content", string.Empty);
var values = new Dictionary<string, string>
{
{ "user_session[email]", "******" },
{ "user_session[password]", "******" },
{ "commit", "inloggen" }, // Not sure if this is actually needed, but it is in the website's request parameters.
{ "authenticity_token", csrf_token }
};
var result = await client.Request("user_session").PostUrlEncodedAsync(values);
}
catch (FlurlHttpException ex)
{
message = ex.Message;
}
Assert.AreEqual("Call failed with status code 404 (Not Found): POST http://www.slimmemeterportal.nl/user_session", message);
}

Mystery solved: As it turns out after some debugging with Wireshark, the website was returning HTTP status code 301. As explained here the default action is to follow the URI in the response's location header using a GET even if the original request was a POST.

How to check if connection to Elasticsearch is established?

I want to check if the connection to Elasticsearch database is ok. In other words I want to ping Elasticsearch. When I execute the code below, an exception is thrown.
public async Task<HealthCheckResult> Execute()
{
if (_configuration.Nodes?.Length == 0)
{
await Task.Delay(1);
return new HealthCheckResult("Connection Failed - Missing elasticsearch connection string")
{
ChildResults = new List<HealthCheckResult>() {new HealthCheckResult()}
};
}
var node = new Uri(_configuration.Nodes.First());
try
{
var connectionPool = new SniffingConnectionPool(new[] {node});
var settings = new ConnectionConfiguration(connectionPool);
var client = new ElasticLowLevelClient(settings);
client.IndicesExists<string>("applications");
}
catch (Exception exception)
{
return new HealthCheckResult(exception.Message)
{
ChildResults = new List<HealthCheckResult>() { new HealthCheckResult() }
};
}
return new HealthCheckResult("Connection Passed")
{
ChildResults = new List<HealthCheckResult>() { new HealthCheckResult() }
};
}
When I execute method above, exception is thrown and I get this message:
Failed sniffing cluster state.
What can I do to check if the connection to Elasticsearch is established?

The Nest IElasticClient interface provides a Ping method for this purpose

I was having the same problem and I managed to fix this by changing the SniffingConnectionPool to a SingleNodeConnectionPool.

Office 365 AdalError.FailedToAcquireTokenSilently

So I've been working for a couple days attempting to create a working example of an application grabbing data, such as a list of the user's contacts, and display it. My attempts so far have be unsuccessful. I have followed a few guides and have read many forums but I can't seem to get them to work.
I got the feeling I have one of the following issues.
Either my application or I do not have the proper permissions on my employer's domain
I am missing a concept
I have a grammatical error in my code.
I have incorrect settings in portal.azure.com or manage.windowsazure.com for my application
As for the where my asp.net project kept breaking here is the code, look at var authResult = await authContext.AcquireTokenSilentAsync(discServResouceId, cc, userid);. I got the original from here AuthenticationHelper
internal class AuthenticationHelper
{
internal static async Task<OutlookServicesClient> EnsureOutlookServicesClientCreatedAsync(string capabilityName)
{
var signInUserId = ClaimsPrincipal.Current.FindFirst(ClaimTypes.NameIdentifier).Value;
var userObjectId =
ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;
var authContext = new AuthenticationContext(SettingsHelper.Authority, new ADALTokenCache(signInUserId));
try
{
var discClient = new DiscoveryClient(SettingsHelper.DiscoveryServiceEndpointUri,
async () =>
{
var cid = SettingsHelper.ClientId;
var appkey = SettingsHelper.AppKey;
var discServResouceId = SettingsHelper.DiscoveryServiceResourceId;
var cc = new ClientCredential(cid, appkey);
var userid = new UserIdentifier(userObjectId, UserIdentifierType.UniqueId);
var authResult = await authContext.AcquireTokenSilentAsync(discServResouceId, cc, userid);
//AcquireTokenSilentAsync is where my application throws an
//AdalException with the error code "AdalError.FailedToAcquireTokenSilently"
return authResult.AccessToken;
});
var dcr = await discClient.DiscoverCapabilityAsync(capabilityName);
return new OutlookServicesClient(dcr.ServiceEndpointUri,
async () =>
{
var authResult = await authContext.AcquireTokenSilentAsync(dcr.ServiceResourceId,
new ClientCredential(SettingsHelper.ClientId,
SettingsHelper.AppKey),
new UserIdentifier(userObjectId,
UserIdentifierType.UniqueId));
return authResult.AccessToken;
});
}
catch (AdalException exception)
{
//Handle token acquisition failure
if (exception.ErrorCode == AdalError.FailedToAcquireTokenSilently)
{
Debug.Print(exception.ErrorCode);
authContext.TokenCache.Clear();
//throw exception;
}
return null;
}
catch (Microsoft.Office365.Discovery.DiscoveryFailedException ex)
{
Debug.Print(ex.Message);
return null;
}
}
}
As far as I know everything is being given to AcquireTokenSilentAsync correctly. For that reason I think it's a permission issue with active directory. Any help is appreciated.

MailChimp Integaration with MVC 5

I am working on an MVC5 project, the client is interested in using MailChimp for sending emails. I have explored the MailChimp and wrappers ( MailChimp.NET ) and tried in my project as well. I tested the REST API as well and it seems to work , for example; I was able to grab lists and templates using REST API. But, still I am having issues with sending email through MailChimp.
So far, I have tried the following code and its working. Now I want to send an email to a newly registered user. Kindly give me detailed code example that How can I achieve this, because I am totally struck here..
var apiKey = "myapikey-us11";
var listId = "mylistid";
var subscribeRequest = new
{
apikey = apiKey,
id = listId,
email = new
{
email = "muhammad.waqas#seventechnology.co.uk"
},
double_optin = true,
};
var requestJson = JsonConvert.SerializeObject(subscribeRequest);
var reqresult = CallMailChimpApi("lists/", requestJson);
CallMailChimApi
private static string CallMailChimpApi(string method, string requestJson)
{
var endpoint = String.Format("https://{0}.api.mailchimp.com/3.0/{1}", "us11", method);
var wc = new WebClient();
try
{
return wc.UploadString(endpoint, requestJson);
}
catch (WebException we)
{
using (var sr = new StreamReader(we.Response.GetResponseStream()))
{
return sr.ReadToEnd();
}
}
}

I Use this function and it work successfully
public void SendEmailByApiMailChimp ()
{
try
{
string UserEmail = " Exemple#gmail.com ";
MailChimpManager mc = new MailChimpManager("16d***********-us14");
EmailParameter email = new EmailParameter()
{
Email = UserEmail
};
EmailParameter resulte = mc.Subscribe("yourlistnumber", email);
var test = resulte;
}
catch (Exception ex)
{
var ters = ex;
}
}