I am using graph.microsoft.com to fetch the exchange online folders and messages. But I am not getting the size of the message and folders in the response. Is there any way to get the message size using the graph Api. Although the size of the attachments is returned in the response. Another problem I am facing is I am not able to fetch all the folders in a mailbox. I was able to fetch all the folders using Exchange Web Service. I have checked the permission level of the folders which were not fetched by the graph api but there was no any such subtle differences when I compared them with the discovered ones.
The Message entity doesn't have a size property. You could suggest one at http://officespdev.uservoice.com/.
You should be able to get folders, as long as their visible to normal clients. Which folders can you not get?