Skip to main content

Using the Office365/Exchange 2016 REST API to access Mailbox data using PowerShell part 5 Sending

Following on from my previous posts in this series, I've made a number of changes to the Exch-REST PowerShell  module to increase its functionality.

The first is that it now supports using either the Microsoft Graph endpoint or the Outlook REST endpoint which has been default so far. If you want to know which endpoint you should use have a look at . The advantage of utilizing the graph endpoint is that it allows you to hook into all the other Office365 services like Groups,OneDrive,SharePoint, Onenote etc using the same endpoint and token (I'll have some example in future posts).

To utilize the graph endpoint is easy all you need to do is add one additional parameter when you create the token to specify you want the AccessToken for the graph eg

$Token = Get-AccessToken -MailboxName `
                         -ClientId 5471030d-f311-4c5d-91ef-74ca885463a7 `
                         -redirectUrl urn:ietf:wg:oauth:2.0:oob         
All the other cmdlets will then look at the AccessToken`s resource property using the new Get-Endpoint function and return the appropriate endpoint. If you want to use the preview endpoints you would need to tweak this function to return the appropriate preview endpoint.

function Get-EndPoint{
        [Parameter(Position=0, Mandatory=$true)] [psObject]$AccessToken,
        [Parameter(Position=1, Mandatory=$true)] [psObject]$Segment
        $EndPoint = ""
            "" {  $EndPoint = "" + $Segment }     
            "" {  $EndPoint = "" + $Segment  }     
        return , $EndPoint
The only quirk I've come across with the difference between the two endpoints is when using extended properties the Name used to identify the Property is PropertyId in the REST endpoint and Id in Graph Endpoint (when making GET). The module has partial coverage for this but its an area that needs some work and will improve with future updates.

I've also added one more AccessToken creation function that allows you to pass in the username and password via a PSCredential. This requires that you have implicit authentication enabled in your app configuration manifest see oauth2AllowImplicitFlow

I've also added functions for Item Creation, Sending messages and Attachment enumeration and downloading and it now stores the Tokens in securestrings.

Also thanks to Elijah Gagne there is also some proper getting started documentation in the GitHub Repo

I've added some samples for using the Send-MessageREST function which is what you would use when you want to send a Message. This function covers all the Send Message bases it can send a Message normally as a user, Send a Message On Behalf or SendAS, and also it can handle allowing you to set the ReplyTo header to allow a different reply to address as well as set Delivery and Read Recipients. The samples page can be found .

A full example that gets an Access token to send a Message with an Attachment would look like

$Mailbox = ""
$Subject = "Test Message"
$Body = "Test Body of Message"
$To = @(New-EmailAddress -Address

$Attachment = @("c:\temp\attachmentfile.doc")

$AccessToken = Get-AccessToken -MailboxName $Mailbox -ClientId 5471030d-f311-4c5d-91ef-74ca885463a7 -redirectUrl urn:ietf:wg:oauth:2.0:oob
Send-MessageREST -MailboxName $Mailbox  -AccessToken $AccessToken -ToRecipients $To -Subject $Subject -Body $Body -Attachments $Attachment   
The module is available from the PowerShell Gallery and the source from Github

Popular posts from this blog

Downloading a shared file from Onedrive for business using Powershell

I thought I'd quickly share this script I came up with to download a file that was shared using One Drive for Business (which is SharePoint under the covers) with Powershell. The following script takes a OneDrive for business URL which would look like This script is pretty simple it uses the SharePoint CSOM (Client side object Model) which it loads in the first line. It uses the URI object to separate the host and relative URL which the CSOM requires and also the SharePointOnlineCredentials object to handle the Office365 SharePoint online authentication. The following script is a function that take the OneDrive URL, Credentials for Office365 and path you want to download the file to and downloads the file. eg to run the script you would use something like ./spdownload.ps1 '

A walk-though using the Graph API Mailbox reports in Powershell

Quite recently the Reporting side of the Graph API has moved in GA from beta, there are quite a number of reports that can be run across various Office365 surfaces but in this post I'm going to focus on the Mailbox related ones. Accessing Office365 Reports using Powershell is nothing new and has been available in the previous reporting endpoint however from the end of January many of these cmdlets are now being depreciated in favour of the Graph API . Prerequisites  In comparison to using the Remote PowerShell cmdlets where only the correct Office365 Admin permissions where needed, to use the new Graph API reports endpoint you need to use OAuth for authentication so this requires an Application Registration  that is then given the correct oAuth Grants to use the Reports EndPoin

How to test SMTP using Opportunistic TLS with Powershell and grab the public certificate a SMTP server is using

Most email services these day employ Opportunistic TLS when trying to send Messages which means that wherever possible the Messages will be encrypted rather then the plain text legacy of SMTP.  This method was defined in RFC 3207 "SMTP Service Extension for Secure SMTP over Transport Layer Security" and  there's a quite a good explanation of Opportunistic TLS on Wikipedia .  This is used for both Server to Server (eg MTA to MTA) and Client to server (Eg a Message client like Outlook which acts as a MSA) the later being generally Authenticated. Basically it allows you to have a normal plain text SMTP conversation that is then upgraded to TLS using the STARTTLS verb. Not all servers will support this verb so if its not supported then a message is just sent as Plain text. TLS relies on PKI certificates and the administrative issue s that come around certificate management like expired certificates which is why I wrote th
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.