Common Functions and Tasks

[This is preliminary documentation and is subject to change.]

Here you can find a series of code snippets and additional information which demonstrate common functions that may be performed using the CFX SDK. You should read the Getting Started section before looking through the examples below.

Publishing or Receiving Encrypted/Secure Messages to/from a Broker (or other Destination)

To enable encrypted/secure message transmission, simply use "amqps://" as the scheme in your Uri instead of "amqp://". By default, all unsecured transmissions are sent using TCP port 5672. All secure transmissions are sent on TCP port 5671.

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AmqpCFXEndpoint endpoint = new AmqpCFXEndpoint();
endpoint.Open("Vendor1.Model1.Machine34");

// Note the user of "amqps://" instead of "amqp://"
Uri uri = new Uri("amqps://mycfxbroker.mydomain.com");           

// Target exchange on broker (shown here in RabbitMQ compatible format)
string amqpTarget = "/exchange/myexchange";
endpoint.AddPublishChannel(uri, amqpTarget);

// Source queue on broker (shown here in RabbitMQ compatible format)
string amqpSource = "/queue/myqueue";
endpoint.AddSubscribeChannel(uri, amqpSource);

Authenticating with a Broker (or other Destination) when Publishing or Receiving Messages

Encode your username and password into the target Uri. Though encrypted communication (AMQPS) is not required, it is highly recommended. If standard AMQP is used, your password will be transmitted in clear text across the network.

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AmqpCFXEndpoint endpoint = new AmqpCFXEndpoint();
endpoint.Open("Vendor1.Model1.Machine34");

// Encode your username and password into the destination Uri
string username = "myusername";
string password = "mypassword";
string hostname = "mycfxbroker.mydomain.com";

//  eg.  amqps://myusername:mypassword@mycfxbroker.mydomain.com
Uri uri = new Uri(string.Format("amqps://{0}:{1}@{2}", username, password, hostname));

// Target exchange on broker (shown here in RabbitMQ compatible format)
string amqpTarget = "/exchange/myexchange";
endpoint.AddPublishChannel(uri, amqpTarget);

// Source queue on broker (shown here in RabbitMQ compatible format)
string amqpSource = "/queue/myqueue";
endpoint.AddSubscribeChannel(uri, amqpSource);

Sending a Direct, Synchronous Request (Request/Response Pattern) to another CFX Endpoint

Use the ExecuteRequest method to make direct requests to other CFX endpoints. This is a syncrhonous (blocking) method. Just as with pub/sub messages, you may use secure communications (AMQPS) for direct point-to-point request/response transactions. Just use "amqps://" in your Uri rather than "amqp://". If the remote CFX endpoint requires authentication, you may pass your username and password in the Uri as well (just as you would with standard pub/sub message transmission).

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string myCFXHandle = "Vendor1.Model1.Machine34";

AmqpCFXEndpoint endpoint = new AmqpCFXEndpoint();
endpoint.Open(myCFXHandle);

string targetEndpointHostname = "machine55.mydomain.com";
string targetCFXHandle = "Vendor2.Model2.Machine55";
string remoteUri = string.Format("amqp://{0}", targetEndpointHostname);

// Set a timeout of 20 seconds.  If the target endpoint does not
// respond in this time, the request will time out.
AmqpCFXEndpoint.RequestTimeout = TimeSpan.FromSeconds(20);

// Build a GetEndpointInfomation Request
CFXEnvelope request = CFXEnvelope.FromCFXMessage(new GetEndpointInformationRequest()
{
    CFXHandle = targetCFXHandle
});

CFXEnvelope response = endpoint.ExecuteRequest(remoteUri, request);

Receiving and Processing Direct, Synchronous Requests (Request/Response Pattern) from other CFX Endpoints

Initialize your endpoint with an inbound request Uri (optional parameter of the Open method). Hook up an event handler to process requests and return responses.

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AmqpCFXEndpoint endpoint;
string myCFXHandle = "Vendor1.Model1.Machine34";
Uri myRequestUri;

public void OpenEndpoint()
{
    endpoint = new AmqpCFXEndpoint();
    myRequestUri = new Uri(string.Format("amqp://{0}", System.Net.Dns.GetHostName()));

    endpoint.OnRequestReceived += Endpoint_OnRequestReceived;
    endpoint.Open(myCFXHandle, myRequestUri);
}

private CFXEnvelope Endpoint_OnRequestReceived(CFXEnvelope request)
{
    // Process request.  Return Result.
    if (request.MessageBody is WhoIsThereRequest)
    {
        CFXEnvelope result = CFXEnvelope.FromCFXMessage(new WhoIsThereResponse()
        { CFXHandle = myCFXHandle, RequestNetworkUri = myRequestUri.ToString(), RequestTargetAddress = "" });
        result.Source = myCFXHandle;
        result.Target = request.Source;
        return result;
    }

    return null;
}

Receiving and Processing Secure Direct, Synchronous Requests (Request/Response Pattern) from other CFX Endpoints

Initialize your endpoint with an inbound request Uri (optional parameter of the Open method). Hook up an event handler to process requests and return responses.

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AmqpCFXEndpoint endpoint;
string myCFXHandle = "Vendor1.Model1.Machine34";
Uri myRequestUri;

public void OpenEndpointSecure()
{
    endpoint = new AmqpCFXEndpoint();
    myRequestUri = new Uri(string.Format("amqps://{0}", System.Net.Dns.GetHostName()));

    // Load certificate from local machine or user certificate store
    X509Certificate2 cert = AmqpUtilities.GetCertificate("MyCertificateName");

    endpoint.OnRequestReceived += Endpoint_OnRequestReceived;
    endpoint.Open(myCFXHandle, myRequestUri, cert);
}

private CFXEnvelope Endpoint_OnRequestReceived(CFXEnvelope request)
{
    // Process request.  Return Result.
    if (request.MessageBody is WhoIsThereRequest)
    {
        CFXEnvelope result = CFXEnvelope.FromCFXMessage(new WhoIsThereResponse()
        { CFXHandle = myCFXHandle, RequestNetworkUri = myRequestUri.ToString(), RequestTargetAddress = "" });
        result.Source = myCFXHandle;
        result.Target = request.Source;
        return result;
    }

    return null;
}