INFO: Save Message to MSG Compound File

• Extended Messaging Application Programming Interface (MAPI), version 1.0
• Microsoft Exchange Windows 3.x client, versions 4.0, 5.0
• Microsoft Exchange Windows NT client, versions 4.0, 5.0
  on the following platforms: NT, x86
• Microsoft Exchange Windows 95 client, versions 4.0, 5.0

SUMMARY

This article contains code that demonstrates how to save a message to a compound document--specifically an .msg file--that is readable by any client that supports the .msg file format.

MORE INFORMATION

The function below takes a valid message object as an in parameter and uses its properties to create a duplicate of the message and save it to a compound file using the .msg format. The subject line of the message is used as the file name of the new file.

NOTE: Special characters in the subject line of the in parameter of this function can cause unexpected results. While code can be written to avoid special characters in the subject line, it is not germane to the topic and such code is intentionally left out.

NOTE: pMessage->CopyTo in the following code may return MAPI_E_NOT_ENOUGH_MEMORY if the message is too large. A large number of recipients or attachments may also contribute to this. The message means that the computer on which the code is running did not have enough free memory to complete the operation. Freeing memory by closing other programs or adding more memory to the computer will correct this.

#define INITGUID
#include <objbase.h>

#define USES_IID_IMessage

#include <mapix.h>
#include <mapitags.h>
#include <mapidefs.h>
#include <mapiutil.h>
#include <mapiguid.h>
#include <imessage.h>

// {00020D0B-0000-0000-C000-000000000046}
DEFINE_GUID(CLSID_MailMessage,
0x00020D0B,
0x0000, 0x0000, 0xC0, 0x00, 0x0, 0x00, 0x0, 0x00, 0x00, 0x46);

HRESULT SaveToMSG ( LPMESSAGE pMessage )
{
    HRESULT hRes = S_OK;
    LPSPropValue pSubject = NULL;
    LPSTORAGE pStorage = NULL;
    LPMSGSESS pMsgSession =  NULL;
    LPMESSAGE pIMsg = NULL;
    SizedSPropTagArray ( 7, excludeTags );
    char szPath[_MAX_PATH];
    char strAttachmentFile[_MAX_PATH];
    LPWSTR lpWideCharStr = NULL;
    ULONG cbStrSize = 0L;

    // create the file name in the directory where "TMP" is defined
    // with subject as the filename and ".msg" extension.

    // get temp file directory
    GetTempPath(_MAX_PATH, szPath);

    // get subject line of message to copy. This will be used as the
    // new file name.
    HrGetOneProp( pMessage, PR_SUBJECT, &pSubject );

    // fuse path, subject, and suffix into one string
    strcpy ( strAttachmentFile, szPath );
    strcat ( strAttachmentFile, pSubject->Value.lpszA  );
    strcat ( strAttachmentFile, ".msg");

    // get memory allocation function
    LPMALLOC pMalloc = MAPIGetDefaultMalloc();

    // Convert new file name to WideChar
    cbStrSize = MultiByteToWideChar (CP_ACP,
                                     MB_PRECOMPOSED,
                                     strAttachmentFile,
                                     -1, lpWideCharStr, 0);

    MAPIAllocateBuffer ( cbStrSize * sizeof(WCHAR),
                            (LPVOID *)&lpWideCharStr );

    MultiByteToWideChar (CP_ACP,
                         MB_PRECOMPOSED,
                         strAttachmentFile,
                         -1, lpWideCharStr, cbStrSize );

    // create compound file
    hRes = ::StgCreateDocfile(lpWideCharStr,
                              STGM_READWRITE |
                              STGM_TRANSACTED |
                              STGM_CREATE, 0, &pStorage);

    // Open an IMessage session.
    hRes = ::OpenIMsgSession(pMalloc, 0, &pMsgSession);

    // Open an IMessage interface on an IStorage object
    hRes = ::OpenIMsgOnIStg(pMsgSession,
                            MAPIAllocateBuffer,
                            MAPIAllocateMore,
                            MAPIFreeBuffer,
                            pMalloc,
                            NULL,
                            pStorage,
                            NULL, 0, 0, &pIMsg);

    // write the CLSID to the IStorage instance - pStorage. This will
    // only work with clients that support this compound document type
    // as the storage medium. If the client does not support
    // CLSID_MailMessage as the compound document, you will have to use
    // the CLSID that it does support.
    hRes = WriteClassStg(pStorage, CLSID_MailMessage );

    // Specify properties to exclude in the copy operation. These are
    // the properties that Exchange excludes to save bits and time.
    // Should not be necessary to exclude these, but speeds the process
    // when a lot of messages are being copied.
    excludeTags.cValues = 7;
    excludeTags.aulPropTag[0] = PR_ACCESS;
    excludeTags.aulPropTag[1] = PR_BODY;
    excludeTags.aulPropTag[2] = PR_RTF_SYNC_BODY_COUNT;
    excludeTags.aulPropTag[3] = PR_RTF_SYNC_BODY_CRC;
    excludeTags.aulPropTag[4] = PR_RTF_SYNC_BODY_TAG;
    excludeTags.aulPropTag[5] = PR_RTF_SYNC_PREFIX_COUNT;
    excludeTags.aulPropTag[6] = PR_RTF_SYNC_TRAILING_COUNT;

    // copy message properties to IMessage object opened on top of
    // IStorage.
    hRes = pMessage->CopyTo(0, NULL,
                            (LPSPropTagArray)&excludeTags,
                            NULL, NULL,
                            (LPIID)&IID_IMessage,
                            pIMsg, 0, NULL );

    // save changes to IMessage object.
    pIMsg -> SaveChanges ( KEEP_OPEN_READWRITE );

    // save changes in storage of new doc file
    hRes = pStorage -> Commit(STGC_DEFAULT);

    // free objects and clean up memory
    MAPIFreeBuffer ( lpWideCharStr );
    pStorage->Release();
    pIMsg->Release();
    CloseIMsgSession ( pMsgSession );

    pStorage = NULL;
    pIMsg = NULL;
    pMsgSession = NULL;
    lpWideCharStr = NULL;

    return hRes;
} 

Additional query words:

Keywords : kbXchge kbMsg kbMAPI100 XCLN
Version : WINDOWS:1.0,4.0,5.0
Platform : WINDOWS
Issue type : kbinfo