Adding your own X-header when sending a message via Exchange Web Services

Thought this was worth a post its something that pretty easy to do with EWS but not something that maybe initially obvious. If you want to add an X-header to a message your sending via Exchange you need to add this via the PS_INTERNET_HEADERS namespace. With EWS you do this when using the MessageType class by adding an Extended property. Eg if you take the basic send message via EWS example from MSDN http://msdn2.microsoft.com/en-us/library/bb408521.aspx and all you need to do is add the following to add your own custom X-header

message.Sensitivity = SensitivityChoicesType.Normal;

// Start X-header Code

PathToExtendedFieldType epExPath1 = new PathToExtendedFieldType();
epExPath1.DistinguishedPropertySetId = DistinguishedPropertySetType.InternetHeaders;
epExPath1.DistinguishedPropertySetIdSpecified = true;
epExPath1.PropertyName = "x-myheader";
epExPath1.PropertyType = MapiPropertyTypeType.String;

ExtendedPropertyType xhXheaderProp = new ExtendedPropertyType();
xhXheaderProp.ExtendedFieldURI = epExPath1;
xhXheaderProp.Item = "blah";
message.ExtendedProperty = new ExtendedPropertyType[] { xhXheaderProp };

// End X-header Code

// Add the message to the array of items to be created.
createItemRequest.Items.Items = new ItemType[1];

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...

EWS-FAI Module for browsing and updating Exchange Folder Associated Items from PowerShell

Folder Associated Items are hidden Items in Exchange Mailbox folders that are commonly used to hold configuration settings for various Mailbox Clients and services that use Mailboxes. Some common examples of FAI's are Categories,OWA Signatures and WorkHours there is some more detailed documentation in the https://msdn.microsoft.com/en-us/library/cc463899(v=exchg.80).aspx protocol document. In EWS these configuration items can be accessed via the UserConfiguration operation https://msdn.microsoft.com/en-us/library/office/dd899439(v=exchg.150).aspx which will give you access to either the RoamingDictionary, XMLStream or BinaryStream data properties that holds the configuration depending on what type of FAI data is being stored. I've written a number of scripts over the years that target particular FAI's (eg this one that reads the workhours http://gsexdev.blogspot.com.au/2015/11/finding-timezone-being-used-in-mailbox.html is a good example ) but I didn't have a gene...

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.

Glen's Exchange and Office 365 Dev Blog

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