mstehle: The CDOs and CDONTS of Messaging Development : WebDAV

FYI: Glen's Exchange Dev Blog is awesome...

mstehle — Wed, 29 Nov 2006 00:51:00 GMT

If you are an Exchange developer and haven't checked out Glen Scales's blog then you are missing out. Chances are he has written part of your project for you and posted it on his blog. Check out his latest post for a script which generates a report of mailbox size broken down by the age of messages...

KB: 919169, Access Denied or 403 Forbidden When Creating Appointments in WebDAV/CDOEX

mstehle — Wed, 22 Nov 2006 00:00:00 GMT

I saw another case on this issue and remembered that I hadn't put this on my blog yet. If you are getting 403's when trying to create an appointment in another user's calendar using WebDAV or an access denied in CDOEX after installing our Send As hotfix (895949) then check out this article...

919169 You cannot save an appointment to another user's calendar by using CDOEX in Exchange Server 2003 after you apply hotfix 895949
http://support.microsoft.com/default.aspx?scid=kb;EN-US;919169

...You will have to open a support incident to get this hotfix....

Note from the article, "In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question."

...In other words you should not be charged for this case if it is opened solely for the purpose of getting the hotfix, any additional troubleshooting or help may incur a cost...

HOWTO: How To Search mv.string Properties using WebDAV

mstehle — Thu, 20 Apr 2006 07:46:00 GMT

...I have posted a new WebDAV sample for using mv.string properties like Keywords and RRule in WHERE clauses, enjoy...

DAV: How To Search mv.string Properties

FYI: New Sample Code! CDOEX & WebDAV How To Add Recurrence to

mstehle — Fri, 10 Mar 2006 05:16:00 GMT

In an effort to provide samples in a organized and repeatable manner, I have created a format for adding code samples to my blog. The code samples will be added as articles which won't get aggregated here. You can also check the TOC to get links to the new sample section as they come available (right now I just have CDOEX and WebDAV section). I will make posts to advertise the new sample additions so that those of you who subscribe to this feed will get notifications but the code itself will be not be in the post. For example...

After struggling to get this just right for items created in Outlook and OWA, I have samples available that add recurrence to a single appointment using CDOEX and WebDAV...

CDOEX: How To Add Recurrence to a Single Appointment

DAV: How To Add Recurrence to a Single Appointment

...Enjoy

HOWTO: Bind to items from CDO/MAPI using WebDAV

mstehle — Wed, 01 Mar 2006 03:50:00 GMT

Summary

Using PR_URL_COMPNAME to bind to an item in WebDAV from CDO/MAPI involves understanding the encoding rules for the Exchange version where the item is homed. These rules are different and incompatiable between Exchange 2000, Exchange 2000 SP 1, and Exchange 2003. These rules are not documented and often require reverse engineering to properly encode URLs.

Reading proptag 0x670E001E via MAPI on a folder or item will return a value such as…

/-FlatUrlSpace-/ca09cf9efaad754e8a85909b04bb255c-12ee443

...which can be appended to a URL and used to access and item or folder via WebDAV…

http://server/exchange/mailbox/-FlatUrlSpace-/ca09cf9efaad754e8a85909b04bb255c-12ee443

More Information

Flat URLs do not have encoding and escaping rules and will work for folders and items in most every DAV operation with the following exceptions:

- as destination of MOVE or COPY operation
- as a source for a DELETE
- for OWA URL commands, e.g. "?cmd=[foo]"

...You are going to use this property in cases where you are stepping out of CDO 1.21 or MAPI code into WebDAV. The HREF in WebDAV is usually created from the subject that was typed in OL (messages created in OWA typically have a GUID file name). The subject in OL can contain characters that must be encoding for use with DAV similar to URL encoding. Rather than figure out those rules, you can use the Flat URL to get the item. The great thing about the proptag is that it is a direct link between MAPI and WebDAV...

...Enjoy...

FYI: Exchange 12 Developer Roadmap...

mstehle — Tue, 06 Dec 2005 03:27:00 GMT

A couple days ago I posted a link to upcoming Outlook Object Model changes and new features, I wanted to go back and note that the Exchange team posted about their developer roadmap as well. This post mentions three new ways of interfacing with Exchange in version 12 that you should be really excited about: web services, agent scripts, and the Monad shell. From what I have seen and heard about E12, I can't help but get excited. The Exchange team has done a great job of listening to the community and delivering product features and enhancements that go a long way towards addressing our wish lists as well as things we never knew to ask for.

...I paid particular attention to the following line about web services in E12, "Our new Web Services will offer remotely-accessible Outlook-compatible business logic for all PIM types." Obviously this sentence is intentionally vague but you should be thinking about a remoteable API that would allow access to Outlook item types like Appointments and Contacts. I don't have specifics on which item types will or will not be supported by the E12 web services, you'll have to keep checking with the Exchange team or my blog to get updates in the coming months.

With the new additions there are things that are being de-emphasized and others that will not be available. Note that WebDAV, CDOEX, and EXOLEDB are the three de-emphasized API's. As they suggest agents will replace CDOEX and EXOLEDB for Exchange server eventing, however Event Sinks will still work against E12.

...It is important to understand the support impact of the word "de-emphasized". From my perspective it means that I will support the use of WebDAV, CDOEX, and EXOLEDB against E12 for entire lifecycle of the product, however the product team will not accept design changes or feature enhancements submitted by me on your behalf regarding these API's. It does mean that these API's will have full break/fix support in which the product team will provide with hotfixes and workarounds. It also means that E13+ will most likely not ship support for these API's.

For every new day there is one that has drawn to a close and with that in mind there are a couple existing API's and developer features not continuing to E12. They are listed in the blog post as well. The most common technologies listed here are Web Forms (custom ASP forms in OWA, much like custom forms in Outlook) and CDOWF (Workflow for Exchange apparently will not be supported in E12). The other technologies are less common but I don't doubt that this will impact many of you.

...Most of the technologies listed here that are going away in E12 will have a much better alternative or had some supportability issues to begin with. For example, ExWin32 or the M: drive, isn't considered an API or development technology at all, we don't support doing any development against it in the current versions of Exchange. Web Forms in OWA are almost always better handled through a custom web application or Sharepoint. Workflow application in Exchange can be better served through BizTalk or the new Windows Workflow Foundation...

FYI: Exchange's CDO 1.21 NOT Supported with Kerberos

mstehle — Wed, 30 Nov 2005 08:03:00 GMT

It's late so I'm going to keep this brief but since we don't have any public content I wanted to get the word out. Exchange's CDO 1.21 was never tested and will not work with Kerberos authentication. While Outlook's version of CDO 1.21 does have Kerberos support, it is not suitable for use in serviced applications.

Problem

A lot people install Exchange System Manager on an IIS box in hopes of using CDO 1.21 inside an ASP application. Typically this ASP application was hosted on the Exchange server itself in the Windows 2000 days but Windows 2003 fully supports Kerberos and this seems like an opportunity to seperate the tiers a bit. What we see people wanting to do is seperate the ASP application to a seperate IIS server with integrated authentication turned on thus allowing users to use this internal web application to pull information from their mailbox or a public folder using their credentials against Exchange through CDO 1.21. What they find is that they get a MAPI_E_LOGON_FAILED error even though they verify the IIS application is running as the logged in user. The problem is that CDO 1.21 doesn't support Kerberos.

Resolution

Unfortunately we can only offer workarounds. CDO 1.21 is old and being de-emphasized in Exchange 12. Here are your options:

Use Basic Authentication. Basic authentication will work because it generates an Interactive token which can be passed to different servers. The drawback with Basic authentication is that users are prompted for a user name and password. Additionally that user name and password is sent in clear text to the server so you should be sure to run your web application with SSL if you are using Basic Authentication.
Use WebDAV. WebDAV uses HTTP requests and responses with XML to query, create, and modify Exchange data. Since you are using HTTP requests, IIS handles authentication and security is much easier to handle. WebDAV can be cumbersome to use but must be given create for its wide supportability (supported with managed code and from non-PC clients) and its ability to support Contacts, Meetings, and Mail Items.
Host your web application on the Exchange server. Since Kerberos is used to pass credentials between servers, if the web application and Exchange are on the same machine there is no need to use Kerberos and your web application will work.

...I thought I was going to keep this brief but I guess not. Anyway, like I said we don't have offical content up yet but I will update this post with the KB article when it goes public. Until then look into WebDAV.

...Update, here is the only offical explaination of this issue that is out there right now...

http://www.microsoft.com/technet/prodtechnol/exchange/2003/insider/providers.mspx

...the most important thing to take away is quoted below..

"EMSMDB32 on the client was modified to support RPC canceling instead of waiting on the server as well as RPC over HTTP and Kerberos authentication. EMSMDB32 on the server went through a series of multithreading changes to improve performance for server applications. EMSABP32 on the client gained the ability to rebind to global catalog servers, where the server version originally did not. MAPI32 was further adapted to work well with third-party providers, while the server version received additional fixes to the temp profile provider."

...Updated 6-02-06...Here is the KB link...http://support.microsoft.com/?kbid=918710

FYI: Supportability of Exchange API's in Managed Code

mstehle — Tue, 22 Nov 2005 23:21:00 GMT

As more and more developers move to managed code (.NET), especially with the release of Visual Studio 2005, it is important to be reminded of what current API's are supported for use in managed code and which are not. The following KB article is a must read when starting .NET development against Exchange, Outlook, or SMTP.

http://support.microsoft.com/default.aspx?scid=kb;en-us;813349

...We all would like to see more supportability with .NET from our Exchange API's. Exchange 12 could offer some more options to that end. It is important to know the basics about all our API's, their functionality limitations, and supportability concerns. Exchange development often requires blending multiple API's to get the job done; you should be open to that possibility.