Introducing Microsoft Exchange Server 2013 : Useful utilities - MFCMAPI

MFCMAPI depends on the availability of Outlook on the workstation on which it runs, and you need to match the correct versions of Outlook and MFCMAPI before MFCMAPI can run. It can be run alongside both Outlook 2010 and Outlook 2013 without any problems. It’s best to run MFCMAPI when Outlook is configured in online mode because this exposes all the mailbox contents to MFCMAPI. Much of the more interesting mailbox contents such as the various subfolders of the Recoverable Items folder structure are not replicated to the PC when Outlook runs in cached Exchange mode.

MFCMAPI began as a training exercise in 2001 for Microsoft developer Stephen Griffin to learn how to program in the Messaging Application Programming Interface (MAPI). The MFC prefix indicates that he used the Microsoft Foundation Class Library as a framework. MFC is a library that encapsulates parts of the Windows API in C++ classes and thus makes it easier for programmers to work with the Windows API (so the theory goes).

Over the past decade, Stephen Griffin has done an incredible job of maintaining MFCMAPI to keep it up to date with the latest versions of Exchange, fix bugs, and add new features. Although Stephen has been working to improve the MFCMAPI user interface, it does not work like Outlook. The advantage delivered by MFCMAPI is that it exposes mailbox internals by using MAPI, so you can expect to encounter MAPI structures and names. It’s easy to figure out, but don’t attempt to make changes unless you know exactly what you are doing. As when operating on Active Directory data with ADSIEdit, it’s possible to cause problems in a mailbox if you make a change in the wrong place.

When you start MFCMAPI, you select an Outlook profile to use to connect to Exchange. MFCMAPI reads the profile data and presents a screen similar to Figure 1. In this instance, you can see that a number of mailboxes are available because they are listed in the profile, including mailboxes that have delegate access. The mailboxes include archive mailboxes linked to the primary mailboxes. The default store—the one to which Exchange delivers email—is marked. You can access on-premises and Office 365 mailboxes and those such as Outlook.com that Outlook accesses through IMAP. You’re not going to send or receive email. All you do with MFCMAPI is investigate and interrogate MAPI structures within mailboxes.

Figure 1. MFCMAPI opening a set of mailboxes

When you open a mailbox, you can navigate through its contents and examine the folders Outlook displays (click Top Of Information Store to reveal your folders) and those it doesn’t, such as Recoverable Items and its subfolders. In Figure 2, you can see the opened Sent Items folder in a mailbox. Twenty-eight items are in the folder. The MAPI properties for the selected message are shown in the bottom pane, and you view full details (or edit) many of these properties by clicking them.

The best way to learn MFCMAPI is to run it to examine mailbox structure and contents. You might like to run the program against a test mailbox and experiment with making changes just to see what you can and cannot do and the effects of making the changes. (The program does prevent you from making changes to some essential data.) Using a test mailbox is probably better than running MFCMAPI against your own production mailbox unless you like to live life on the edge of a razor.

Apart from examining mailboxes to learn how Exchange organizes data, when should you use MFCMAPI to solve problems? One common example is if a mailbox has become corrupt for some reason, and you need to work with Microsoft support to resolve the problem. In this scenario, you’re likely to be told exactly what to do, and you might have to remove items that are suspected of being corrupt. Exchange might deem a mailbox to be corrupt if too many threads freeze when a client attempts to retrieve data. In this case, the only access to the mailbox is possible through a program such as MFCMAPI. If the user can identify the items that cause the freeze, you could remove them by using MFCMAPI to see whether your action addresses the problem.

Figure 2. Navigating within a mailbox with MFCMAPI

The best thing about MAPI is the extensive feature set it enables for clients such as Outlook and, in its server-side variants, Exchange server. I guess you could argue that MAPI has been very persistent in that the name first appeared as “simple MAPI” in Microsoft Mail way back in the dim and distant early nineties. The functionality you can build on the 12 functions supported by simple MAPI is barely sufficient to create and send messages and can’t approach the kind of feature set in Outlook 2013, but it was a start.

Powerful as it is, MAPI has never attracted much developer enthusiasm outside Microsoft and has been viewed as an API that should be approached only when necessary. The lack of good documentation is one possible reason, and the result is that only heavy-duty engineering projects, such as those to create MAPI providers that allow Outlook to access non-Microsoft servers, have used MAPI. (Inside MAPI [Irving De La Cruz and Irving Thaler: Microsoft Press, 1996] has been out of print for many years.)

Microsoft has shipped many other messaging-related APIs in an attempt to make Exchange data more accessible or usable, including esoteric offerings such as Collaborative Data Objects (CDO) Routing (released with Exchange Server 5.5) and WebDAV (which was supposed to be the next great thing when Exchange Server 2000 was released). However, MAPI remains optimal, which is why tools such as MFCMAPI remain so important.

Over the past few years, Exchange Web Services (EWS) has transformed matters. EWS is now the recommended API for developers who want to access and work with the contents of the Exchange Store. Microsoft uses EWS for clients such as Outlook 2011 for Macintosh and Outlook Web App, and plans are in place to extend EWS further as new versions of Exchange appear, probably to close the functionality gap between EWS clients and the MAPI-based Outlook. As far as I am aware, no plan exists to discard MAPI for EWS in the short-to-medium future, but this is a possibility when EWS supports the same feature set as MAPI does today.

In the interim, it seems that EWS is a good thing to know something about. The Exchange Web Services Editor (EWSEditor, http://ewseditor.codeplex.com/) is another Codeplex project that’s built on top of .NET Framework 3.5. Like MFCMAPI, versions of EWSEditor are released on a regular basis and work with on-premises servers running Exchange 2007, Exchange 2010, or Exchange 2013. The utility also supports Office 365. If you have questions about how to program using EWS, you can find many examples and advice on MVP Glen Scales’s website (http://www.gsexdev.blogspot.com/).