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POUsing MSMQ over HTTP. How to address the queue?
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  1. POUsing MSMQ over HTTP. How to address the queue?
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    copied!<p>I'm currently trying to use MSMQ with C# and .NET in order to achieve IPC. I am trying to understand how it works, and I'm quite confused about the <a href="http://blogs.msdn.com/b/johnbreakwell/archive/2009/02/26/difference-between-path-name-and-format-name-when-accessing-msmq-queues.aspx" rel="nofollow noreferrer">differences between Path name and Format name when accessing MSMQ queues</a>. I've found some similar issues in the following posts:</p> <ol> <li><a href="https://stackoverflow.com/questions/9488010/msmq-calls-over-http-not-reaching-destination-queue">MSMQ calls over HTTP not reaching destination queue</a></li> <li><a href="https://stackoverflow.com/questions/19156136/how-to-setup-msmq-server-so-that-it-can-be-accessed-over-the-internet">How to setup MSMQ server so that it can be accessed over the Internet</a></li> <li><a href="https://stackoverflow.com/questions/4499091/how-to-use-msmq-over-http-through-the-respective-wcf-binding">How to use MSMQ over http through the respective WCF binding?</a></li> </ol> <p>However, they're all using MSMQ and WCF, and I don't want to use WCF for now.</p> <p>What I want to achieve is the following:</p> <p><strong>Client:</strong> Sends data to the queue through <strong>http</strong>.</p> <p><strong>Server:</strong> Receives data from the queue through <strong>http</strong>.</p> <p>My point here is that I want that either <em>server, client and the queue</em> to be hosted in potentially different computers. (For now I'm testing everything in the same machine).</p> <p>Here I have the following code, which demonstrates what I have in mind:</p> <p>First, I create the queue:</p> <pre><code>if(!System.Messaging.MessageQueue.Exists(@".\Private$\SimplestExamplePrivateQueue"); System.Messaging.MessageQueue.Create(@".\Private$\SimplestExamplePrivateQueue"); </code></pre> <p><strong>Client code:</strong></p> <p>Then, at the client side, I have a callback function which is invoked when the user presses a button in order to send a message.</p> <pre><code>private void button1_Click(object sender, System.EventArgs e) { try { // Create a connection to the queue System.Messaging.MessageQueue mq = new System.Messaging.MessageQueue(@"FormatName:Direct=http://localhost/msmq/Private$/SimplestExamplePrivateQueue"); // Create a point object to send Point myPoint = new Point (Convert.ToInt32(textBox2.Text), Convert.ToInt32(textBox3.Text)) ; // Send object mq.Send (myPoint) ; } // Catch the exception that signals all types of error // from the message queueing subsystem. Report error // to the user. catch (System.Messaging.MessageQueueException mqx) { MessageBox.Show (mqx.Message) ; } </code></pre> <p>Everything until here works fine.</p> <p><strong>Server code:</strong></p> <p>Then, I have a button which invokes a callback function to synchronously read one message from the queue at the server side:</p> <pre><code>private void button1_Click(object sender, EventArgs e) { try { // Create a connection to the queue var mq = new MessageQueue(@"Direct=http://localhost/msmq/Private$/SimplestExamplePrivateQueue"); // Set the queue's formatter to decode Point objects mq.Formatter = new XmlMessageFormatter(new[] {typeof (Point)}); // Receive message synchronously Message msg = mq.Receive(); // Convert received message to object that we think was sent var pt = (Point) msg.Body; // Display it to the user MessageBox.Show(pt.ToString(), "Received Point"); } // Report any exceptions to the user. A timeout would cause such // an exception catch (Exception x) { MessageBox.Show(x.Message); } } </code></pre> <p>In my (limited) understanding of MSMQ, this should work. However, when I call <code>Message msg = mq.Receive();</code> I get the following exception:</p> <pre><code>The specified format name does not support the requested operation. For example, a direct queue format name cannot be deleted. </code></pre> <p>And the Stack Trace: </p> <pre><code>at System.Messaging.MessageQueue.MQCacheableInfo.get_ReadHandle() at System.Messaging.MessageQueue.StaleSafeReceiveMessage(UInt32 timeout, Int32 action, MQPROPS properties, NativeOverlapped* overlapped, ReceiveCallback receiveCallback, CursorHandle cursorHandle, IntPtr transaction) at System.Messaging.MessageQueue.ReceiveCurrent(TimeSpan timeout, Int32 action, CursorHandle cursor, MessagePropertyFilter filter, MessageQueueTransaction internalTransaction, MessageQueueTransactionType transactionType) at System.Messaging.MessageQueue.Receive() at InternetQueueingRecipient.Form1.button1_Click(Object sender, EventArgs e) in c:\Users\felipedalcin\Documents\MSMQ\MSMQandNET\InternetQueuing\InternetQueueingRecipient\Form1.cs:line 85 </code></pre> <p>Does anyone have an idea of how I could debug this or even if what I want to do is achievable by those means?</p>
 

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