Office 365 REST API (Python) Mark Email as Read

At first glance it looks OK. I wonder if the Content-Type header isn't being set to "application/json" or something along those lines. Try getting a network trace and verify that the request looks something like:

PATCH https://outlook.office365.com/api/v1.0/Me/Messages('msgid') HTTP/1.1
Accept: application/json;odata.metadata=full
Authorization: Bearer <token>
Content-Type: application/json;odata.metadata=full
Host: outlook.office365.com
Content-Length: 24
Expect: 100-continue
Connection: Keep-Alive

{
  "IsRead": "true"
}

Well I have an answer for myself and it is indeed a simple matter. It was a mistake to not fully read how PATCH is different from GET or POST. In short it's important to make sure your headers are set for the right content-type.

Here is the working code:

# once file acquired mark the email as read
changes = {u'IsRead':u'True'}
headers = {'Content-Type': 'application/json'}
json_changes = json.dumps(changes)
base_email_url = u'https://outlook.office365.com/api/v1.0/me/messages/{0}'.format( msgId )
response = requests.patch(base_email_url, data=json_changes, auth=__AUTH, headers=headers)
log.debug( response )