Wednesday, May 13, 2015

Working with Referance Attachments in EWS on Exchange Online

Last year a new feature was introduced into Exchange Online to allow you to create an Attachment where the Attachment resided on OneDrive rather then the traditional Email attachment approach you can read more about this here http://blogs.office.com/2014/10/08/introducing-new-way-share-files-outlook-web-app/ there was also an Ignite session you can watch on how this has evolved https://channel9.msdn.com/Events/Ignite/2015/BRK2196. MAPI has always had a rich set of attachment types since Exchange's inception to deal with Rich Text Messaging eg the various attachment types you can encounter are listed in https://msdn.microsoft.com/en-us/library/office/cc815439.aspx  . In EWS these attachment types where simplified some what into either Item Attachments (for Attached Store Items) or File Attachments. To cater for this new feature a new Attachment Type called a
ReferenceAttachment has been introduced into EWS in Exchange Online. To see the
ReferenceAttachmentType you need to have your requested Server version set to Exchange2003_SP1 else the attachment will just be returned as a FileAttachment .  Essential this is what you will see in a EWS Response when you have a reference attachment

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                  <t:ReferenceAttachment>
                    <t:AttachmentId Id="AAMkADczNDE4YWE...." />
                    <t:Name>lb.txt</t:Name>
                    <t:ContentType>image/png</t:ContentType>
                    <t:ContentId>7cc92386-bee2-4db8-ae81-d17dad9350f8</t:ContentId>
                    <t:Size>598</t:Size>
                    <t:LastModifiedTime>2015-05-08T06:39:22</t:LastModifiedTime>
                    <t:IsInline>false</t:IsInline>
                    <t:AttachLongPathName>https://domain-my.sharepoint.com/personal/gscales_datarumble_com/Documents/Email%20attachments/lb.txt</t:AttachLongPathName>
                    <t:ProviderType>OneDrivePro</t:ProviderType>
                    <t:PermissionType>2</t:PermissionType>
                    <t:AttachmentIsFolder>false</t:AttachmentIsFolder>
                  </t:ReferenceAttachment>

If your using Proxy code and you've updated your WSDL proxies you should be able to use the  ReferenceAttachmentType to access the AttachLongPathName property etc. If your using the EWS Managed API there currently is no support for Reference Attachments in the last released version or the Open Source Repo https://github.com/OfficeDev/ews-managed-api . So I've forked the open source repo and added support in for this (note its read only support) into my GitHub repo https://github.com/gscales/ews-managed-api . For those that just want the binaries https://github.com/gscales/EWS-Binaries/blob/master/RAFork-Microsoft.Exchange.WebServices.zip Note this is patched build not a stable build so use it at your own risk.

To use this in code with the CSOM to download the Attachment from One drive looks like

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            FindItemsResults<Item> fiResults = service.FindItems(WellKnownFolderName.Inbox, new ItemView(1));
            Item Message = fiResults.Items[0];
            Message.Load();
            foreach (Attachment Attachment in Message.Attachments)
            {
                if (Attachment is ReferenceAttachment)
                {
                    ReferenceAttachment rfAttach = (ReferenceAttachment)Attachment;
                    Console.WriteLine(rfAttach.ProviderType);
                    Console.WriteLine(rfAttach.AttachLongPathName);

                    var credentials = new Microsoft.SharePoint.Client.SharePointOnlineCredentials(username, securedPassword);
                    Uri url = new Uri(rfAttach.AttachLongPathName);
                    Microsoft.SharePoint.Client.ClientContext clientContext = new Microsoft.SharePoint.Client.ClientContext("https://" + url.Host);
                    clientContext.Credentials = credentials;
                    Microsoft.SharePoint.Client.FileInformation fileInfo = Microsoft.SharePoint.Client.File.OpenBinaryDirect(clientContext, url.LocalPath);
                    FileStream fs = new FileStream("c:\\temp\\" + rfAttach.Name, FileMode.Create);
                    fileInfo.Stream.CopyTo(fs);
                    fs.Flush();
                    fs.Close();

                }   

            }

Or in a Script that will download the last email in the Mailbox and download any reference attachments from that message I've put a download of this script here

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####################### 
<# 
.SYNOPSIS 
 Download any OneDrive Attachments on the last message received in a Mailbox in Exchange Online 
 
.DESCRIPTION 
 Using the EWS Managed API and the Sharepoint CSOM this scripts downloads the any OneDrive Attachments
 on the last message received in a Mailbox in Exchange Online 
 
 Requires Forked version of the EWS Managed API dll from 
 https://github.com/gscales/EWS-Binaries/blob/master/RAFork-Microsoft.Exchange.WebServices.zip
 Requires Sharepoint CSOM

.EXAMPLE
 PS C:\>Download-LastOneDriveAttachment  -MailboxName user.name@domain.com -FilePath c:\temp

 This example downloads any OneDrive Attachments on the last message received in a Mailbox to the c:\temp directory
#> 
function Download-LastOneDriveAttachment 
{ 
    [CmdletBinding()] 
    param( 
    [Parameter(Position=0, Mandatory=$true)] [string]$MailboxName,
 [Parameter(Position=0, Mandatory=$true)] [string]$FilePath
    )  
 Begin
 {
  $SharePointClientDll = (($(Get-ItemProperty -ErrorAction SilentlyContinue -Path Registry::$(Get-ChildItem -ErrorAction SilentlyContinue -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SharePoint Client Components\'|Sort-Object Name -Descending| Select-Object -First 1 -ExpandProperty Name)).'Location') + "ISAPI\Microsoft.SharePoint.Client.dll")
  Add-Type -Path $SharePointClientDll 
  
  ## Load Managed API dll note forked version to support referance attachments
  $EWSDLL = "c:\temp\Microsoft.Exchange.WebServices.dll"
  Import-Module $EWSDLL
    
  ## Set Exchange Version  
  $ExchangeVersion = [Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2013_SP1 
  
  ## Create Exchange Service Object  
  $service = New-Object Microsoft.Exchange.WebServices.Data.ExchangeService($ExchangeVersion)  
    
  ## Set Credentials to use two options are availible Option1 to use explict credentials or Option 2 use the Default (logged On) credentials  
    
  #Credentials Option 1 using UPN for the windows Account  
  $psCred = Get-Credential  
  $creds = New-Object System.Net.NetworkCredential($psCred.UserName.ToString(),$psCred.GetNetworkCredential().password.ToString())  
  $soCredentials =  New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($psCred.UserName.ToString(),$psCred.password)
  $service.Credentials = $creds      
  #Credentials Option 2  
  #service.UseDefaultCredentials = $true  
    
  ## Choose to ignore any SSL Warning issues caused by Self Signed Certificates  
    
  ## Code From http://poshcode.org/624
  ## Create a compilation environment
  $Provider=New-Object Microsoft.CSharp.CSharpCodeProvider
  $Compiler=$Provider.CreateCompiler()
  $Params=New-Object System.CodeDom.Compiler.CompilerParameters
  $Params.GenerateExecutable=$False
  $Params.GenerateInMemory=$True
  $Params.IncludeDebugInformation=$False
  $Params.ReferencedAssemblies.Add("System.DLL") | Out-Null

  $TASource=@'
    namespace Local.ToolkitExtensions.Net.CertificatePolicy{
      public class TrustAll : System.Net.ICertificatePolicy {
        public TrustAll() { 
        }
        public bool CheckValidationResult(System.Net.ServicePoint sp,
          System.Security.Cryptography.X509Certificates.X509Certificate cert, 
          System.Net.WebRequest req, int problem) {
          return true;
        }
      }
    }
'@ 
  $TAResults=$Provider.CompileAssemblyFromSource($Params,$TASource)
  $TAAssembly=$TAResults.CompiledAssembly

  ## We now create an instance of the TrustAll and attach it to the ServicePointManager
  $TrustAll=$TAAssembly.CreateInstance("Local.ToolkitExtensions.Net.CertificatePolicy.TrustAll")
  [System.Net.ServicePointManager]::CertificatePolicy=$TrustAll

  ## end code from http://poshcode.org/624
    
  ## Set the URL of the CAS (Client Access Server) to use two options are availbe to use Autodiscover to find the CAS URL or Hardcode the CAS to use  
    
  #CAS URL Option 1 Autodiscover  
  $service.AutodiscoverUrl($MailboxName,{$true})  
  "Using CAS Server : " + $Service.url   
     
  #CAS URL Option 2 Hardcoded  
    
  #$uri=[system.URI] "https://casservername/ews/exchange.asmx"  
  #$service.Url = $uri    
    
  ## Optional section for Exchange Impersonation  
 }
    Process
    {
  # Bind to the Inbox Folder
  $folderid= new-object Microsoft.Exchange.WebServices.Data.FolderId([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Inbox,$MailboxName)   
  $Inbox = [Microsoft.Exchange.WebServices.Data.Folder]::Bind($service,$folderid)
  #Define ItemView to retrive just 1000 Items    
  $ivItemView =  New-Object Microsoft.Exchange.WebServices.Data.ItemView(1)   
  $psPropset= new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.BasePropertySet]::FirstClassProperties)  
  $fiItems = $service.FindItems($Inbox.Id,$ivItemView)    
  [Void]$service.LoadPropertiesForItems($fiItems,$psPropset)  
     foreach($Item in $fiItems.Items){      
   Write-Host ("Processing : " + $Item.Subject)
   foreach($Attachment in $Item.Attachments){
    if($Attachment -is [Microsoft.Exchange.WebServices.Data.ReferenceAttachment]){
     $DownloadURI = New-Object System.Uri($Attachment.AttachLongPathName);
      $SharepointHost = "https://" + $DownloadURI.Host
       $clientContext = New-Object Microsoft.SharePoint.Client.ClientContext($SharepointHost)
       $clientContext.Credentials = $soCredentials;
       $destFile = $FilePath + "\" + [System.IO.Path]::GetFileName($DownloadURI.LocalPath)
       $fileInfo = [Microsoft.SharePoint.Client.File]::OpenBinaryDirect($clientContext, $DownloadURI.LocalPath);
      $fstream = New-Object System.IO.FileStream($destFile, [System.IO.FileMode]::Create);
      $fileInfo.Stream.CopyTo($fstream)
      $fstream.Flush()
       $fstream.Close()
      Write-Host ("File downloaded to " + ($destFile))
    }
   }          
     }    
 }
 End{}
}