Skip to main content

Downloading Attachments and Exporting Email as eml files in the EWS Managed API using Powershell

A common and useful thing you may want to do in Powershell when working with Exchange Email automation is to download an attachment. When working with Exchange Web Services you first need to use a GetItem operation to work out what attachments are on a message then use a GetAttachment operation which returns a Byte Array of each attachments content. So all you need to do with this Byte array is write it out to a file using the System.IO.FileStream Class.

To do this you first need a message object that you would normally get doing a GetItem operation in EWS in the managed API its just one line once you know the MessageID. Eg

$msMessage = [Microsoft.Exchange.WebServices.Data.EmailMessage]::Bind($service,$MessageID)


Once you have the message object you will have a list of attachments and the attachmentID you need to make a GetAttachment operations. Again this is pretty easy to do using the Managed API which extrapolates the GetAttachment operation as the load method on an attachment object.

$fileName = “C:\temp”
foreach($attach in $msMessage.Attachments){
$attach.Load()
$fiFile = new-object System.IO.FileStream(($fppath + “\” + $attach.Name.ToString()), [System.IO.FileMode]::Create)
$fiFile.Write($attach.Content, 0, $attach.Content.Length)
$fiFile.Close()
write-host "Downloaded Attachment : " + (($fppath + “\” + $attach.Name.ToString())
}


In Exchange Web Services you have the ability to export the whole message in a serialized EML format (this is different from a Compound message format msg file which contains all the Mapi properties related to the rich types of the Exchange store). To do this when you do the original Get-Item operation request for the message you need to make sure you also request the MIME content of the message. This MIME content will contain the RFC serialized copy of the message which you can write out to a file. Eg

$psPropset = new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.ItemSchema]::MimeContent)
$msMessage = [Microsoft.Exchange.WebServices.Data.EmailMessage]::Bind($service,$MessageID,$psPropset)
Then similar to the above attachment example you can write that MIME content out to filestream. Eg
$fileName = “C:\temp\exportedmail.eml”
$fiFile = new-object System.IO.FileStream($fileName, [System.IO.FileMode]::Create) $fiFile.Write($msMessage.MimeContent.Content, 0,$msMessage.MimeContent.Content.Length)
$fiFile.Close()

Popular posts from this blog

The MailboxConcurrency limit and using Batching in the Microsoft Graph API

If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background   The Mailbox  concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons.  Batching in the Gr...

Exporting and Uploading Mailbox Items using Exchange Web Services using the new ExportItems and UploadItems operations in Exchange 2010 SP1

Two new EWS Operations ExportItems and UploadItems where introduced in Exchange 2010 SP1 that allowed you to do a number of useful things that where previously not possible using Exchange Web Services. Any object that Exchange stores is basically a collection of properties for example a message object is a collection of Message properties, Recipient properties and Attachment properties with a few meta properties that describe the underlying storage thrown in. Normally when using EWS you can access these properties in a number of a ways eg one example is using the strongly type objects such as emailmessage that presents the underlying properties in an intuitive way that's easy to use. Another way is using Extended Properties to access the underlying properties directly. However previously in EWS there was no method to access every property of a message hence there is no way to export or import an item and maintain full fidelity of every property on that item (you could export the...

EWS Create Mailbox folder Powershell module for Exchange and Office365 Mailboxes

This is a rollup post for a couple of scripts I've posted in the past for creating folders using EWS in an Exchange OnPremise or Exchange online Cloud mailbox. It can do the following Create a Folder in the Root of the Mailbox Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test Create a Folder as a SubFolder of the Inbox Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Inbox' Create a Folder as a SubFolder of the Inbox using EWS Impersonation Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Inbox' -useImpersonation Create a new Contacts Folder as a SubFolder of the Mailboxes Contacts Folder Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Contacts' -FolderClass IPF.Contact Create a new Calendar Folder as a SubFolder of the Mailboxes Calendar Folder Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -Parent...
All sample scripts and source code is provided by for illustrative purposes only. All examples are untested in different environments and therefore, I cannot guarantee or imply reliability, serviceability, or function of these programs.

All code contained herein is provided to you "AS IS" without any warranties of any kind. The implied warranties of non-infringement, merchantability and fitness for a particular purpose are expressly disclaimed.