Glen's Exchange and Office 365 Dev Blog

Guest access is one of the ways in Office365 of collaborating between different organizations which allows you to give certain people who are outside of your company access to a limited subset of the resources you have in the Cloud. This can be an Office365 unified Group or Microsoft Team but also other workloads like SharePoint and OneDrive can utilize this. When it comes to scripting there are a number of value add things you can do to automate tasks for different people who have guest accounts in another tenant. The first step to automating with Guest Access is to Authenticate and generate an access token in the Guest tenant. Getting the Guest Tenants Authorization Endpoint Before you can authenticate you need to first obtain the Guest tenants Authorization endpoint for the tenant where the Guest Account exists in. To do this you can make a simple Get Request like the following Invoke-WebRequest -uri ("[https://login.windows.net/{0}/.well-known/openid-configu...

Office365 Groups (or unified\modern groups) is a new feature the was introduced in Office365 that Exchange Online is an active participant in by providing the Email/Conversation and calendar portions of this feature. Recently there was a new unified REST API released in preview https://msdn.microsoft.com/en-us/office/office365/howto/office-365-unified-api-overview  that I'll look at another day but with this post I want to look at just accessing the Exchange portion of the unified Groups using EWS and also we will take a look at how the config is stored in the mailbox. Accessing using the EWS Managed API If your following the changes to the EWS Managed API open source repository https://github.com/OfficeDev/ews-managed-api  support for reading the available Unified groups a Mailbox is a member of was added in April. This is done using the yet to be documented GetUserUnifiedGroups EWS operation. So if you have a version of the Ma...