I am trying to read in emails using mailbee from a gmail inbox. The idea is to take any winmail.dat and extract its attachments and add them to the attachment pool so we don't have to do it manually. MailBee won't recognize the winmail.dat I send with my testmail as a Tnef file, (the file's type is Tnef attachment type). the IsTnef comes out as false.
I couldn't find alot of info about mailbee tnef attachments, any ideas?
This is what I got:
var attachments = message.Attachments.Cast<MailBeeAttachment>().ToList();
var encapsulated = attachments.Where(a => a.IsTnef).SelectMany(a => a.GetAttachmentsFromTnef().Cast<MailBeeAttachment>());
// Add encapsulated attachments
attachments.AddRange(encapsulated);
You probably want to continue using MailBee... but in case you are open to alternatives, let me answer this question as if you were using my open source MimeKit/MailKit libraries instead:
When MimeKit's MIME parser encounters attachments with a Content-Type header that matches application/vnd.ms-tnef or application/ms-tnef, it will automatically use the special-purpose TnefPart class to represent that attachment.
To extract the encapsulated attachments from that, you can simply use the
ExtractAttachments() method which probably works a lot like MailBee's GetAttachmentsFromTnef() method.
The translation of your code from MailBee to MimeKit would look like this:
var attachments = message.Attachments.ToList();
var encapsulated = attachments.OfType<TnefPart>().SelectMany(a => a.ExtractAttachments ());
// Add encapsulated attachments
attachments.AddRange(encapsulated);
Most likely the reason that MailBee's IsTnef property is returning false for you, however, is probably because the Content-Type header doesn't match the tnef mime-types I mentioned earlier. If that is indeed the case, then the translated code I posted above will also fail under MimeKit.
However...
MimeKit also provides lower-level TNEF support classes that you can use if you decide to use an alternative method for determining of a MIME part contains TNEF content.
static void ExtractAttachments (MimePart attachment, IList<MimeEntity> attachments)
{
using (var reader = new TnefReader (attachment.ContentObject.Open (), 0, TnefComplianceMode.Loose)) {
// skip past the non-attachment tnef content...
while (reader.ReadNextAttribute ()) {
if (reader.AttributeLevel == TnefAttributeLevel.Attachment)
break;
}
if (reader.AttributeLevel == TnefAttributeLevel.Attachment)
ExtractAttachments (reader, attachments);
}
}
static void ExtractAttachments (TnefReader reader, IList<MimeEntity> attachments)
{
var attachMethod = TnefAttachMethod.ByValue;
var filter = new BestEncodingFilter ();
var prop = reader.TnefPropertyReader;
MimePart attachment = null;
int outIndex, outLength;
TnefAttachFlags flags;
string[] mimeType;
byte[] attachData;
string text;
do {
if (reader.AttributeLevel != TnefAttributeLevel.Attachment)
break;
switch (reader.AttributeTag) {
case TnefAttributeTag.AttachRenderData:
attachMethod = TnefAttachMethod.ByValue;
attachment = new MimePart ();
break;
case TnefAttributeTag.Attachment:
if (attachment == null)
break;
while (prop.ReadNextProperty ()) {
switch (prop.PropertyTag.Id) {
case TnefPropertyId.AttachLongFilename:
attachment.FileName = prop.ReadValueAsString ();
break;
case TnefPropertyId.AttachFilename:
if (attachment.FileName == null)
attachment.FileName = prop.ReadValueAsString ();
break;
case TnefPropertyId.AttachContentLocation:
text = prop.ReadValueAsString ();
if (Uri.IsWellFormedUriString (text, UriKind.Absolute))
attachment.ContentLocation = new Uri (text, UriKind.Absolute);
else if (Uri.IsWellFormedUriString (text, UriKind.Relative))
attachment.ContentLocation = new Uri (text, UriKind.Relative);
break;
case TnefPropertyId.AttachContentBase:
text = prop.ReadValueAsString ();
attachment.ContentBase = new Uri (text, UriKind.Absolute);
break;
case TnefPropertyId.AttachContentId:
attachment.ContentId = prop.ReadValueAsString ();
break;
case TnefPropertyId.AttachDisposition:
text = prop.ReadValueAsString ();
if (attachment.ContentDisposition == null)
attachment.ContentDisposition = new ContentDisposition (text);
else
attachment.ContentDisposition.Disposition = text;
break;
case TnefPropertyId.AttachData:
var stream = prop.GetRawValueReadStream ();
var content = new MemoryStream ();
var guid = new byte[16];
if (attachMethod == TnefAttachMethod.EmbeddedMessage) {
var tnef = new TnefPart ();
foreach (var param in attachment.ContentType.Parameters)
tnef.ContentType.Parameters[param.Name] = param.Value;
if (attachment.ContentDisposition != null)
tnef.ContentDisposition = attachment.ContentDisposition;
attachment = tnef;
}
// read the GUID
stream.Read (guid, 0, 16);
// the rest is content
using (var filtered = new FilteredStream (content)) {
filtered.Add (filter);
stream.CopyTo (filtered, 4096);
filtered.Flush ();
}
content.Position = 0;
attachment.ContentTransferEncoding = filter.GetBestEncoding (EncodingConstraint.SevenBit);
attachment.ContentObject = new ContentObject (content);
filter.Reset ();
attachments.Add (attachment);
break;
case TnefPropertyId.AttachMethod:
attachMethod = (TnefAttachMethod) prop.ReadValueAsInt32 ();
break;
case TnefPropertyId.AttachMimeTag:
mimeType = prop.ReadValueAsString ().Split ('/');
if (mimeType.Length == 2) {
attachment.ContentType.MediaType = mimeType[0].Trim ();
attachment.ContentType.MediaSubtype = mimeType[1].Trim ();
}
break;
case TnefPropertyId.AttachFlags:
flags = (TnefAttachFlags) prop.ReadValueAsInt32 ();
if ((flags & TnefAttachFlags.RenderedInBody) != 0) {
if (attachment.ContentDisposition == null)
attachment.ContentDisposition = new ContentDisposition (ContentDisposition.Inline);
else
attachment.ContentDisposition.Disposition = ContentDisposition.Inline;
}
break;
case TnefPropertyId.AttachSize:
if (attachment.ContentDisposition == null)
attachment.ContentDisposition = new ContentDisposition ();
attachment.ContentDisposition.Size = prop.ReadValueAsInt64 ();
break;
case TnefPropertyId.DisplayName:
attachment.ContentType.Name = prop.ReadValueAsString ();
break;
}
}
break;
case TnefAttributeTag.AttachCreateDate:
if (attachment != null) {
if (attachment.ContentDisposition == null)
attachment.ContentDisposition = new ContentDisposition ();
attachment.ContentDisposition.CreationDate = prop.ReadValueAsDateTime ();
}
break;
case TnefAttributeTag.AttachModifyDate:
if (attachment != null) {
if (attachment.ContentDisposition == null)
attachment.ContentDisposition = new ContentDisposition ();
attachment.ContentDisposition.ModificationDate = prop.ReadValueAsDateTime ();
}
break;
case TnefAttributeTag.AttachTitle:
if (attachment != null && string.IsNullOrEmpty (attachment.FileName))
attachment.FileName = prop.ReadValueAsString ();
break;
case TnefAttributeTag.AttachMetaFile:
if (attachment == null)
break;
// TODO: what to do with the meta data?
break;
case TnefAttributeTag.AttachData:
if (attachment == null || attachMethod != TnefAttachMethod.ByValue)
break;
attachData = prop.ReadValueAsBytes ();
filter.Flush (attachData, 0, attachData.Length, out outIndex, out outLength);
attachment.ContentTransferEncoding = filter.GetBestEncoding (EncodingConstraint.EightBit);
attachment.ContentObject = new ContentObject (new MemoryStream (attachData, false));
filter.Reset ();
attachments.Add (attachment);
break;
}
} while (reader.ReadNextAttribute ());
}
Of course... you could also just cheat by doing this:
var tnef = new TnefPart { ContentObject = attachment.ContentObject };
attachments.AddRange (tnef.ExtractAttachments ());
So the end result might look like this (if you decide to match against the FileName instead):
var attachments = message.Attachments.ToList();
var encapsulated = attachments.OfType<MimePart>()
.Where(x => (x is TnefPart) || x.FileName == "winmail.dat")
.SelectMany(x => {
var tnef = (x as TnefPart) ?? new TnefPart { ContentObject = x.ContentObject };
return tnef.ExtractAttachments ();
});
// Add encapsulated attachments
attachments.AddRange(encapsulated);