Skip to main content

Writing a simple scripted process to download attachmentts in Exchange 2007/ 2010 using the EWS Managed API

Every complicated thing in life is made up of smaller simpler building blocks, when it comes to writing a script (or any code really) the more of these little building blocks you have to figure out the more the process of solving a problem can become bewildering. The Internet generally provides you with lots of half eaten sandwiches of information something someone else has taken a bite out but a lot of the time half done, and as with any code its usefulness declines over time as new and better API's and methods are derived. In this post I'm going to go through a simple scripted process that hopefully covers a few more of these smaller building blocks that you might face when asked to come up with a simple costless solution to perform an automated business function with a script.

So the process im going to look at is one that comes up a lot and that is you have an Email that comes into to certain mailbox every day with a certain subject in my case "Daily Export" this email has an attachment that must be downloaded to a fileserver. After the message is downloaded the email should then be moved into a processed folder which is a subfolder of the inbox of the mailbox and marked as Read.

So first this script will be designed to be run once a day from a scheduled task. First off with this script is we need a few variables that need to be hardcoded with some settings.

$MailboxName = "user@mailbox.com"

This is the emailaddress of the mailbox the script is going to retrieve the message from

$Subject = "Daily Export"

This is the subject of the Email that has the attachment to process.

$ProcessedFolderPath = "/Inbox/Processed"

This is the Folder path to where the message is going to moved to this is needed for the fuction that will find the FolderID of this folder which is important when you go to move messages with EWS.

$downloadDirectory = "c:\temp\"

This is the folder where attachments will be downloaded to

The next part of this script is the FindTargetFolder function this is a function that takes a folderpath in the format of /FirstLevelFolder/SecondLevelFolder etc and then uses this to find the folderID of the folder when the email once processed will be moved to.

The next part of the script is some standard EWS Managed API Powershell stuff that I've talked about a lot before in this post

Then we come to the search filter which is a little interesting this search filter is doing a bitwise AND which means that all three conditions must be meet for it to return items.

$Sfir = new-object Microsoft.Exchange.WebServices.Data.SearchFilter+IsEqualTo([Microsoft.Exchange.WebServices.Data.EmailMessageSchema]::IsRead, $false)
$Sfsub = new-object Microsoft.Exchange.WebServices.Data.SearchFilter+IsEqualTo([Microsoft.Exchange.WebServices.Data.ItemSchema]::Subject, $Subject)
$Sfha = new-object Microsoft.Exchange.WebServices.Data.SearchFilter+IsEqualTo([Microsoft.Exchange.WebServices.Data.EmailMessageSchema]::HasAttachments, $true)
$sfCollection = new-object Microsoft.Exchange.WebServices.Data.SearchFilter+SearchFilterCollection([Microsoft.Exchange.WebServices.Data.LogicalOperator]::And);

So what this filter does is looks for Emails that are unread, have attachments and have a subject "Daily Export". If all these are true then these items will be returned into the finditems collection which brings us to the next part of the script.

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

This part of the script loads the messsages and then loops through the attachments and downloads them to the specified path.

$miMailItems.isread = $true
$miMailItems.Update([Microsoft.Exchange.WebServices.Data.ConflictResolutionMode]::AlwaysOverwrite)

These two lines set the message to read and then updates it.

[VOID]$miMailItems.Move($Global:findFolder.Id.UniqueId)

This last line moves the message to the processed folder.

That's it although generally not really but its as far as this half eaten sandwich is going to go but its pretty easy from here. I've put a download of this script here
Labels:

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...
Read more

Sending a MimeMessage via the Microsoft Graph using the Graph SDK, MimeKit and MSAL

One of the new features added to the Microsoft Graph recently was the ability to create and send Mime Messages (you have been able to get Message as Mime for a while). This is useful in a number of different scenarios especially when trying to create a Message with inline Images which has historically been hard to do with both the Graph and EWS (if you don't use MIME). It also opens up using SMIME for encryption and a more easy migration path for sending using SMTP in some apps. MimeKit is a great open source library for parsing and creating MIME messages so it offers a really easy solution for tackling this issue. The current documentation on Send message via MIME lacks any real sample so I've put together a quick console app that use MSAL, MIME kit and the Graph SDK to send a Message via MIME. As the current Graph SDK also doesn't support sending via MIME either there is a workaround for this in the future my guess is this will be supported.
Read more

Export calendar Items to a CSV file using Microsoft Graph and Powershell

For the last couple of years the most constantly popular post by number of views on this blog has been  Export calendar Items to a CSV file using EWS and Powershell closely followed by the contact exports scripts. It goes to show this is just a perennial issue that exists around Mail servers, I think the first VBS script I wrote to do this type of thing was late 90's against Exchange 5.5 using cdo 1.2. Now it's 2020 and if your running Office365 you should really be using the Microsoft Graph API to do this. So what I've done is create a PowerShell Module (and I made it a one file script for those that are more comfortable with that format) that's a port of the EWS script above that is so popular. This script uses the ADAL library for Modern Authentication (which if you grab the library from the PowerShell gallery will come down with the module). Most EWS properties map one to one with the Graph and the Graph actually provides better information on recurrences then...
Read more
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.