Glen's Exchange and Office 365 Dev Blog

As the information on how to do this would cover multiple posts, I've bound this into a series of mini post docs in my GitHub Repo to try and make this subject a little easier to understand and hopefully navigate for most people.   The Binder index is  https://gscales.github.io/Graph-Powershell-101-Binder/   The topics covered are How you can access the Recoverable Items Folders (and get the size of these folders)  How you can access and search for items in the Deletions and Purges Folders and also how you can Export an item to an Eml from that folder How you can Restore a Deleted Item back to the folder it was deleted from (using the Last Active Parent FolderId) and the sample script is located  https://github.com/gscales/Powershell-Scripts/blob/master/Graph101/Dumpster.ps1

For an updated article on this problem please have a read of https://glenscales.substack.com/p/application-is-over-its-mailboxconcurrency 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...

I haven't done a basics series for a while but based on some of the questions I've been getting lately and the lack of some good Mailbox specific examples for basic but more complex tasks using the Graph against Exchange Online Mailboxes this seemed like a good series to write. For all the scripts in this series I'm not going to use any modules or other libraries so everything will be using Invoke-WebRequest and Invoke-RestMethod, while there is nothing wrong with using libraries or modules and a number of advantages in doing so it just keeps the examples as simple and easy to understand as they can be. Authentication  You can't have an article on the Graph without talking about authentication and we are now far from the past where all you needed was a simple username and password and you where off to the races. The basics of Authentication are is that first you will need an Azure App Registration (that has been consented to), there are many pages dedicated to how you c...

Microsoft have just released the Mail.ReadBasic permission into beta for the Microsoft Graph endpoint  https://developer.microsoft.com/en-us/graph/blogs/new-basic-read-access-to-a-users-mailbox/ which is a much needed addition that allows the creation of automation and apps that can just access messages at a more meta information level without having access to the Body or Attachments. Privacy and security are always pressing issues especially around email so this can turn down the privacy concerns while also reduce the security concerns of giving full access to content.  Lets look at one use case for this new permission which is getting the Message Headers from a Message that has arrived in a users Mailbox that you suspect might be spam but you want the header information to do some analysis. Normally if you wanted to build an app to automate this you would have to at least assign Mail.Read which would give full access to all email content in a Mailbox (either deleg...

One of the features that is currently in beta in the Microsoft Graph API is an operation that will let you unsubscribe from any mailing list that supports the List-Unsubscribe header in a message that complies with RFC-2369 (https://docs.microsoft.com/en-us/graph/api/message-unsubscribe?view=graph-rest-beta). This can have a number of uses one that does come to mind is when you have staff that are leaving the company (or even taking an extended break where they won't be reading their email) and they have signed up to quite of number of mailing lists. As part of your deprovisioning process you can include a script that will unsubscribe from the emails in a Mailbox before you remove the account instead of deleting and hoping the NDR's do it for you. The RFC state the following for List-Unsubscribe 3.2. List-Unsubscribe The List-Unsubscribe field describes the command (preferably using mail) to directly unsubscribe the user (removing them from the list). Examples...

Group calendars have always been one of the big asks for in any group collaboration programs back from Lotus Notes to Microsoft Exchange and now Microsoft Teams. There are a few ways of getting a Group calendar working in Teams, one is hosting the OWA web apps see or some other people advocate using a SharePoint calendar and hosting that similarly. Here is a different method you can use by taking advantage of being able to call the Graph API in a  Tab application. The getSchedule Graph action (still currently in beta) allows you to query up to 62 days of Freebusy information on up to 100 calendars in a single call this makes it a good option for this type of application. So as long as users can view each others calendars or have detailed freebusy permissions the action should return the le vel of detail required for a Group calendar.   The other thing you can do with the Graph API is get the users photo and build a nice legend for the Group calendar also. To make this visu...

First a little news about Exchange Identifiers that you may have missed (its not often that something like this changes so its rather exciting) When you access an item in an Exchange Mailbox store whether its OnPrem or in the Cloud you use the Identifier of the particular item which will vary across whatever API your using. Eg MAPI - PR_EntryId eg NameSpace.GetItemFromID(EntryId) EWS -  EWSId eg EmailMessage.Bind(service,ewsid) Rest -   RestId  eg  https://graph.microsoft.com/v1.0/me/messages('restid') The advice over the years has always been its not a good idea to store these Id's in something like a database because they change whenever and Item is moved. Eg if an Item is moved from the Inbox to a Subfolder in the Inbox it will received a different Id so whatever you have stored in your database suddenly becomes invalid and its not easy to reconcile this. However a new feature that has appeared in Exchange Online in Beta with the Graph API is imm...

I've had some time recently to do some much needed updates to my Exch-Rest module so it now supports both Azure Cloud Shell and PowerShell Core on Linux (tested on RHEL,CentOS, Debian and Ubuntu). So now you can logon to an Office365 Mailbox using this Module with Powershell on Linux and send Email or a Skype for Business Message or do some mailbox reporting eg The requirements on Linux is you need to be using the latest version of PowerShell core installed as per  https://docs.microsoft.com/en-us/powershell/scripting/setup/installing-powershell-core-on-linux?view=powershell-6 .This ensures that all the required .net Core libraries will be available as older version of .Net core didn't have some of the libraries I'm using and I didn't want to backport for older versions.  Also because there are no Linux forms to interact with for authentication you need to pass in the credentials to use via a PSCredential and the code will use the password grant to get the Token e...

A little background The LAPFID property is an extended property that gets set on an Exchange Store Item when its deleted (any type of delete soft or hard) that is the enabler for the original folder item recovery feature that rolled out to both Exchange Online and Exchange OnPrem (2016) last year. If you where to look at this property in a MAPI editor it would look like the following To understand what that property Id value represents you need to first understand a little bit more about the Folder EntryId format (PR_EntryId) that exchange uses which is documented in this Exchange Protocol Document https://msdn.microsoft.com/en-us/library/ee217297(v=exchg.80).aspx . A different visual representation of this with the individual components highlighted would look something like this Hopefully from this you can see that the LAPFID is comprised of the DatabaseGUID and GlobalCounter constituents of the FolderEntryId. To make sense of the  LAPFID you need to resolve it back ...