Add creator to shared calender entry event sink

One of the big pains i find when your using a shared calendar in a public folder is that you can't easily tell which user has created each of the calendar entries. I came up with the following sink for a small project I'm working on that will append the name of the creator to the location field of an appointment or meeting request when its created (this will mean it will appear in brackets when you look at the normal calendar view next to each appointment). You can grab the creator of a item from the "http://schemas.microsoft.com/mapi/proptag/0x3FF8001E" mapi property.

Sub ExStoreEvents_OnSave(pEventInfo, bstrURLItem, lFlags)
on error resume next
Const EVT_NEW_ITEM = 1
Const EVT_IS_DELIVERED = 8

If (lFlags And EVT_IS_DELIVERED) Or (lFlags And EVT_NEW_ITEM) Then
set apptobj = CreateObject("CDO.Appointment")
apptobj.datasource.open bstrURLItem,,3
creator = " Created by " & apptobj.fields("http://schemas.microsoft.com/mapi/proptag/0x3FF8001E").Value
apptobj.fields("urn:schemas:calendar:location") = apptobj.fields("urn:schemas:calendar:location") & creator
apptobj.fields.update
apptobj.datasource.save
end if
set apptobj = nothing

End Sub

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...

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.

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...

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