Skip to main content

Setting properties via EWS on a Draft message in a Compose Mail App

With the latest updates that have been released recently for Compose apps that are now available in OWA in Office365 and the Office/Exchange 16 preview the ability to extend what your compose apps can do has been greatly enhanced. With version 1.3 of the API you can now save an Item via the saveAsync method https://msdn.microsoft.com/en-us/library/office/mt269096.aspx .

Why this small change is important from an extensibility point of view is that when you save an Item this way, it creates a draft in the Mailbox you activated the compose app from which you can then modify anyway you like using the EWS updateItem operation. (normally you would be restricted in a compose app to just using the subset of properties and methods provided for in the Office.js).

One trick however is the ItemId which you need to make an UpdateItem EWS Request to update the Draft Item is still only available in Read Mode. So to get around this I've come up with the following workaround

  1. Set a custom property on the draft Item using the Mail App Custom properties method using something like https://msdn.microsoft.com/EN-US/library/office/fp142263.aspx . With my Mail Apps I generate a new GUID for the app session that I use as the value.
  2. Save the Item your composing as a Draft using saveAync
  3. Now you can use makeEwsRequestAsync to do a findItems on the drafts folder of the Mailbox with a restriction so it only finds the Item with the Custom property you have set. The Custom properties you can set in the Mail App API are documented in https://msdn.microsoft.com/en-us/library/hh968549(v=exchg.80).aspx . But basically what you have is they are a named property within the PS_PUBLIC_STRING propset of type String. The property name of the property is prefixed with cecp- and rest of the property name is the GUID of your Mail Apps as defined in the application's manifest Id .
  4. Once you have the ItemId and Change key you can then use UpdateItem in EWS to update any of the extended or strongly type properties on the draft Message.
One thing to note to use this workaround your Mail App needs the ReadWriteMailbox privilege to allow the use of the EWS Operations. I've put together a sample of using this workaround in my OWA Voting button app.

Also because this is using version 1.3 of the Mail App Api you should set the requirements in the Manifest file of your application eg

  <Requirements>
    <Sets DefaultMinVersion="1.3">
      <Set MinVersion="1.3" Name="Mailbox"></Set>
    </Sets>
  </Requirements>

This will mean your Mail App will only activate in clients that support version 1.3 which means at the moment it won't activate in Outlook 2013.

Labels

Labels:

Popular posts from this blog

Exporting and Uploading Mailbox Items using Exchange Web Services using the new ExportItems and UploadItems operations in Exchange 2010 SP1

Two new EWS Operations ExportItems and UploadItems where introduced in Exchange 2010 SP1 that allowed you to do a number of useful things that where previously not possible using Exchange Web Services. Any object that Exchange stores is basically a collection of properties for example a message object is a collection of Message properties, Recipient properties and Attachment properties with a few meta properties that describe the underlying storage thrown in. Normally when using EWS you can access these properties in a number of a ways eg one example is using the strongly type objects such as emailmessage that presents the underlying properties in an intuitive way that's easy to use. Another way is using Extended Properties to access the underlying properties directly. However previously in EWS there was no method to access every property of a message hence there is no way to export or import an item and maintain full fidelity of every property on that item (you could export the...
Read more

Sending a Message in Exchange Online via REST from an Arduino MKR1000

This is part 2 of my MKR1000 article, in this previous post  I looked at sending a Message via EWS using Basic Authentication.  In this Post I'll look at using the new Outlook REST API  which requires using OAuth authentication to get an Access Token. The prerequisites for this sketch are the same as in the other post with the addition of the ArduinoJson library  https://github.com/bblanchon/ArduinoJson  which is used to parse the Authentication Results to extract the Access Token. Also the SSL certificates for the login.windows.net  and outlook.office365.com need to be uploaded to the devices using the wifi101 Firmware updater. To use Token Authentication you need to register an Application in Azure https://msdn.microsoft.com/en-us/office/office365/howto/add-common-consent-manually  with the Mail.Send permission. The application should be a Native Client app that use the Out of Band Callback urn:ietf:wg:oauth:2.0:oob. You ...
Read more

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...
Read more
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.