Writing MSMQ Client for MAPI Transport Provider

#include <windows.h>
#include "mq.h"

int main(void)
{
    /*
     * Algorithm:
     *  1. Open MSMQ MAPI Transport inbound queue.
     *  2. Prepare MQMSGPROPS struct.
     *  3. Send a message to the queue.
     */

    // I assume this queue name. Replace this as necessary.
    #define MY_IN_QUEUE_PATHNAME L"mig\\nokuntseff_mqxp"
 
    // Determine format name of the incoming queue
    wchar_t wcsQueueFormatName[MAX_PATH];
    DWORD dwSize = MAX_PATH;
    HRESULT hRes = ::MQPathNameToFormatName(MY_IN_QUEUE_PATHNAME,
           wcsQueueFormatName,
           &dwSize);
    if (FAILED(hRes))
        throw (-1);

    // Open it.
    QUEUEHANDLE hInQueue = NULL;
    hRes = ::MQOpenQueue(wcsQueueFormatName,
       MQ_SEND_ACCESS,
       MQ_DENY_NONE,
       &hInQueue);
    if (FAILED(hRes))
        throw (-1);

    // Prepare MQMSGPROPS struct.
    MQMSGPROPS MsgProps;

    // We'll send message body only. Arrays of size 1 are enough.
    MQPROPVARIANT aVariant[1];
    MSGPROPID aPropId[1];
 
    // Define simple message in MSMQ mail format
    char * pszMessage = "Mime-Version: 1.0\r\n"
      "Date: 9 Apr 1998 17:58:44 +0700\r\n"
      "From: Nik Okuntseff<xpp_outbound>\r\n"
      "Subject: Hello, world!\r\n"
      "X-Delivery-Report-Requested: False\r\n"
      "X-Non-Delivery-Report-Requested: True\r\n"
      "Content-Transfer-Encoding: binary\r\n"
      "To: Nik Okuntseff<nokuntseff_mqxp>\r\n"
      "\r\n"          // Empty line separates message body
      "Hello, world!\r\n";      // Message body
    DWORD dwMessageSize = strlen(pszMessage);

    // Set the PROPID_M_BODY property.
    aPropId[0] = PROPID_M_BODY;        // PropId
    aVariant[0].vt = VT_VECTOR | VT_UI1;     // Type
    aVariant[0].caub.cElems = dwMessageSize;    // Size.
    aVariant[0].caub.pElems = (unsigned char *) pszMessage; // Message itself

    // Set the MQMSGPROPS structure
    MsgProps.cProp = 1;    // Number of properties.
    MsgProps.aPropID = aPropId;  // Ids of properties.
    MsgProps.aPropVar = aVariant; // Values of properties.
    MsgProps.aStatus = NULL;  // No error report.

    hRes = ::MQSendMessage(hInQueue,
       &MsgProps,
       NULL);
    if (FAILED(hRes))
        throw (-1);

    // Close the queue
    hRes = ::MQCloseQueue(hInQueue);
    if (FAILED(hRes))
        throw (-1);

    return 0;
}

This sample is very similar to the XConClient sample. Algorithm is the same. Message queue is of course different. The message body which is sent to the queue is also different. The "To:" and "From:" fields are constructed in format that MAPI transport can understand. Notice that the queue label alone is used as the recipient address (we had it prefixed with a user alias when dealing with MSMQ Exchange connector).

You may use this sample to send the "Hello, world!" message to a MAPI recipient. Reply to this message in a MAPI client and observe outbound message appear in the outbound queue (xpp_outbound in my case).