Skip to main content

Processing Meeting requests remotely with WebDAV and OWA

This was something interesting I learned this week. If you want to process meeting requests remotely the same way you can locally with CDOEX then using a combination of WebDAV and some OWA commands can make this happen.

Process the request

Basically when someone invites you to a meeting you will get sent a calendar message that contains all the invitation information. You can differentiate this from a normal message by looking at the DAV:Contentclass and seeing if its set to urn:content-classes:calendarmessage. Now if you want to scan a inbox for any of these messages you could do a WebDAV search against that mailbox for any messages that have this particular content class and also who’s outlookmessage class was set to IPM.Schedule.Meeting.Request which delineates this as a meeting request. Eg

server = "servername"
mailbox = "mailbox"
strURL = "http://" & server & "/exchange/" & mailbox & "/inbox/"
strQuery = ""
strQuery = strQuery & "SELECT ""DAV:href"", ""http://schemas.microsoft.com/exchange/outlookmessageclass"""
strQuery = strQuery & " FROM scope('shallow traversal of """
strQuery = strQuery & strURL & """') Where ""DAV:ishidden"" = False AND ""DAV:isfolder"" = False AND "
strQuery = strQuery & """DAV:contentclass"" = 'urn:content-classes:calendarmessage'"
set req = createobject("microsoft.xmlhttp")
req.open "SEARCH", strURL, false
req.setrequestheader "Content-Type", "text/xml"
req.setRequestHeader "Translate","f"
req.send strQuery
If req.status >= 500 Then
wscript.echo "Status: " & req.status & " Status text: An error occurred on the server."
ElseIf req.status = 207 Then
wscript.echo "Status: " & req.status & " Status text: An error occurred on the server."
set oResponseDoc = req.responseXML
set oNodeList = oResponseDoc.getElementsByTagName("a:href")
set oclasslist = oResponseDoc.getElementsByTagName("d:outlookmessageclass")
For i = 0 To (oclasslist.length -2)
set oNode1 = oclasslist.nextNode
set oNode = oNodeList.nextNode
if oNode1.Text = "IPM.Schedule.Meeting.Request" then acceptcalmess(oNode.Text)
Next
Else
wscript.echo "Status: " & req.status & " Status text: An error occurred on the server."
End If

sub acceptcalmess(objhref)
wscript.echo objhref
end sub

Now to process the calendar messages this is where you can use the OWA accept and decline commands. Once you issue one of these commands OWA will create a new calendar response message saying that you have accepted or declined this meeting and save this into your drafts folder (the original calendar request message is also deleted). To send this message all you then need to do is move it to the DavMailSubmissionURI. To put this all together with the search example it would look like this

server = "servername"
mailbox = "mailbox"
strURL = "http://" & server & "/exchange/" & mailbox & "/inbox/"
strQuery = ""
strQuery = strQuery & "SELECT ""DAV:href"", ""http://schemas.microsoft.com/exchange/outlookmessageclass"""
strQuery = strQuery & " FROM scope('shallow traversal of """
strQuery = strQuery & strURL & """') Where ""DAV:ishidden"" = False AND ""DAV:isfolder"" = False AND "
strQuery = strQuery & """DAV:contentclass"" = 'urn:content-classes:calendarmessage'"
set req = createobject("microsoft.xmlhttp")
req.open "SEARCH", strURL, false
req.setrequestheader "Content-Type", "text/xml"
req.setRequestHeader "Translate","f"
req.send strQuery
If req.status >= 500 Then
wscript.echo "Status: " & req.status
wscript.echo "Status text: An error occurred on the server."
ElseIf req.status = 207 Then
wscript.echo "Status: " & req.status
wscript.echo "Status text: " & req.statustext
set oResponseDoc = req.responseXML
set oNodeList = oResponseDoc.getElementsByTagName("a:href")
set oclasslist = oResponseDoc.getElementsByTagName("d:outlookmessageclass")
For i = 0 To (oclasslist.length -2)
set oNode1 = oclasslist.nextNode
set oNode = oNodeList.nextNode
if oNode1.Text = "IPM.Schedule.Meeting.Request" then acceptcalmess(oNode.Text)
Next
Else
wscript.echo "Status: " & req.status
wscript.echo "Status text: " & req.statustext
wscript.echo "Response text: " & req.responsetext
End If

sub acceptcalmess(objhref)

Req.open "GET", objhref & "?cmd=Accept", false
Req.send
wscript.echo req.status
sDestinationURL = "http://" & server & "/exchange/" & mailbox & "/##DavMailSubmissionURI##/"
sSource = replace(lcase(objhref),"/inbox/","/drafts/")
req.open "MOVE", sSource, False
req.setRequestHeader "Destination", sDestinationURL
req.setRequestHeader "Content-Type", "message/rfc822;"
req.setRequestHeader "Translate", "f"
req.setRequestHeader "Content-Length:", Len(xmlstr)
req.send(xmlstr)
wscript.echo req.status
end sub

The last thing you might want to do in regards to processing calendar messages is to process that actual responses that come back from people so that the attendee status in the appointment is updated with accepted, rejected and any new attendees that are invited. To do this all you need to do is open the responses with the open cmd from OWA and OWA will process the request and update the meeting appropriately. To identify the response calendar messages from a request calendar messages you can use the Oulookmessageclass and see if its of type IPM.Schedule.Meeting.Resp.Pos, IPM.Schedule.Meeting.Resp.Neg, IPM.Schedule.Meeting.Resp.Tent .

server = "servername"
mailbox = "username"
strURL = "http://" & server & "/exchange/" & mailbox & "/inbox/"
strQuery = ""
strQuery = strQuery & "SELECT ""DAV:href"", ""http://schemas.microsoft.com/exchange/outlookmessageclass"""
strQuery = strQuery & " FROM scope('shallow traversal of """
strQuery = strQuery & strURL & """') Where ""DAV:ishidden"" = False AND ""DAV:isfolder"" = False AND "
strQuery = strQuery & """DAV:contentclass"" = 'urn:content-classes:calendarmessage' "
set req = createobject("microsoft.xmlhttp")
req.open "SEARCH", strURL, false
req.setrequestheader "Content-Type", "text/xml"
req.setRequestHeader "Translate","f"
req.send strQuery
If req.status >= 500 Then
wscript.echo "Status: " & req.status
wscript.echo "Status text: An error occurred on the server."
ElseIf req.status = 207 Then
wscript.echo "Status: " & req.status
wscript.echo "Status text: " & req.statustext
set oResponseDoc = req.responseXML
set oNodeList = oResponseDoc.getElementsByTagName("a:href")
set oclasslist = oResponseDoc.getElementsByTagName("d:outlookmessageclass")
For i = 0 To (oclasslist.length -2)
set oNode1 = oclasslist.nextNode
set oNode = oNodeList.nextNode
select case oNode1.Text
case "IPM.Schedule.Meeting.Resp.Neg" acceptcalmess(oNode.Text)
case "IPM.Schedule.Meeting.Resp.Tent" acceptcalmess(oNode.Text)
case "IPM.Schedule.Meeting.Resp.Pos" acceptcalmess(oNode.Text)
end select
Next
Else
wscript.echo "Status: " & req.status
wscript.echo "Status text: " & req.statustext
wscript.echo "Response text: " & req.responsetext
End If

sub acceptcalmess(objhref)

Req.open "GET", objhref & "?cmd=Open", false
Req.send
wscript.echo req.status
end sub



Note processing the meeting responses this way does not delete the response you have to do this manually.

What about task requests?
Task requests seem to be a little different OWA for example doesn’t give you the option to process task requests. So this method is really not applicable.

Popular posts from this blog

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

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.
Read more

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...
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.