Friday, April 17, 2009

Using the EWS Managed API with powershell

If you missed it the first public beta of Exchange 2010 was released this week while I'm not one for getting two excited over beta's there was one other important release this week which was the beta release of the EWS Managed API. Why this is a little more exciting then a new version of Exchange is that you can actually start using this now to access Exchange Web Services on a Exchange 2007 Server. What makes this component a little more significant if you have done any programming in EWS even if it just sending raw XML to and from the server you may have noticed that at times this can be difficult and the interface isn't that intuitive. So what the EWS Managed API sets out to do is provide you with a interface that makes writing Exchange code a more intuitive experience by essential normalising the logic and the interfaces you use. While there are still some inescapable realities of writing Exchange code like Mapi properties etc (If you have missed them there has been some great posts recently on Mapi properties on the Exchange blog see) this is a much needed addition.

For anybody who wants to write simple Powershell scripts that access Exchange mailbox data your going to love this API. Lets look at how to get started and then you can start buring some daylight.

Requirments

The EWS Managed API requires the workstation where your running this from to have .NET 3.5 installed. The RTM version of Powershell will work fine with 3.5 so there's no need for V2. You then need to download and Install the EWS Managed API first from here

Coding

First you need to load the DLL

$dllpath = "C:\Program Files\Microsoft\Exchange\Web Services\1.0\Microsoft.Exchange.WebServices.dll"
[void][Reflection.Assembly]::LoadFile($dllpath)


Now you can create a ExchangeService object if your going to be coding against 2007 you must explictly set the version.

$service = new-object Microsoft.Exchange.WebServices.Data.ExchangeService([Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2007_SP1)

Depending on where your running this code if you can make use of Autodiscover then all you need to do is provide the email address and the component will autodicover the CAS server to use. eg

$service.AutodiscoverUrl("email@domain.com")

You may not however want to hardcode the users email address in a script so what you might want to do is grab the email address using ADSI by using the Users SID eg.

$windowsIdentity = [System.Security.Principal.WindowsIdentity]::GetCurrent()
$sidbind = "LDAP://<SID=" + $windowsIdentity.user.Value.ToString() + ">"
$aceuser = [ADSI]$sidbind

$service.AutodiscoverUrl($aceuser.mail.ToString())

If you can't use Autodiscover and you want to hardcode the URI then you could use

$uri=[system.URI] "https://casservername/ews/exchange.asmx"
$service.Url = $uri

If you dont want to use the currently logged on users credentials then you can specifiy your own
$service.Credentials = New-Object System.Net.NetworkCredential("username","password","domain")

You can also make use of Impersonation if you so wish but i haven't got a sample for that yet. But once you have connected and authenticated against EWS you can then use some simple code to do a varitety of things here one sample of showing the number of unread email and that last received email's details

$inbox = [Microsoft.Exchange.WebServices.Data.Folder]::Bind($service, [Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Inbox)
"Number or Unread Messages : " + $inbox.UnreadCount
$view = New-Object Microsoft.Exchange.WebServices.Data.ItemView(1)
$findResults = $service.FindItems([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Inbox,$view)
""
"Last Mail From : " + $findResults.Items[0].From.Name
"Subject : " + $findResults.Items[0].Subject
"Sent : " + $findResults.Items[0].DateTimeSent

If your running this against a development server that has self signed certificates then there is another thing you need to add to your code to make it capable of dealing with self signed certificates. Because you cant use delegates in the RTM version of Powershell you need to use a workaround there is this one
or http://poshcode.org/624

For more samples have a look at Exchange development portal.


I've put a download of these scripts here

4 comments:

Gorkem said...

Hi Glen,

Thank you very much for this post, EWS Managed API is a major improvement over the proxy classes, that's for sure.
Just a few quick fixes on the non-Autodiscover script:
Line 41 needs to read:
$uri=[system.URI] ("https://" + $casserverName + "/ews/exchange.asmx")

The second concatenation operator needs to be + instead of & and the whole string operation needs to be put in parantheses

On line 17, the namespace has to read Local.ToolkitExtensions rather than Com.Marchview.

Thank you for sharing your code!

Glen said...

Thanks for the fixes much apprecaited I've updated that script. I had a few different versions of the certificate class and I managed to post the one that didn't work :(. You've already helped a few people out that had the same problem.

Cheers
Glen

Anonymous said...

Can you think of a reason why the Microsoft.Exchange.WebServices.dll would not be found on an Exchange 2010 installation? I cannot take advantage of all of this wonderfulness if the dll is not there. It is also not part of the Exchange Web Services SDK download. :(

aloneguid said...

Because EWS is just a web service, why would you need a .NET library to use it?