Do the same thing for AttachmentCollection.AddAsync()

Also added unit tests.
jstedfast · Feb 7, 2024 · a4bcf3e · a4bcf3e
1 parent 9f63257
commit a4bcf3e
Show file tree

Hide file tree

Showing 2 changed files with 73 additions and 11 deletions.
diff --git a/MimeKit/AttachmentCollection.cs b/MimeKit/AttachmentCollection.cs
@@ -289,19 +289,33 @@ MimeEntity CreateAttachment (ContentType contentType, bool autoDetected, string
 			return attachment;
 		}
 
-		async Task<MimeEntity> CreateAttachmentAsync (ContentType contentType, string path, Stream stream, bool copyStream, CancellationToken cancellationToken)
+		async Task<MimeEntity> CreateAttachmentAsync (ContentType contentType, bool autoDetected, string path, Stream stream, bool copyStream, CancellationToken cancellationToken)
 		{
 			var fileName = GetFileName (path);
-			MimeEntity attachment;
+			MimeEntity attachment = null;
 
 			if (contentType.IsMimeType ("message", "rfc822")) {
-				var message = await MimeMessage.LoadAsync (stream, cancellationToken).ConfigureAwait (false);
+				long position = stream.CanSeek ? stream.Position : 0;
 
-				if (!copyStream)
-					stream.Dispose ();
+				try {
+					var message = await MimeMessage.LoadAsync (stream, cancellationToken).ConfigureAwait (false);
+
+					if (!copyStream)
+						stream.Dispose ();
 
-				attachment = new MessagePart { Message = message };
-			} else {
+					attachment = new MessagePart { Message = message };
+				} catch (FormatException) {
+					if (autoDetected && stream.CanSeek) {
+						// If the contentType was auto-detected and the stream is seekable, fall back to attaching this content as a generic stream
+						contentType = new ContentType ("application", "octet-stream");
+						stream.Position = position;
+					} else {
+						throw;
+					}
+				}
+			}
+
+			if (attachment is null) {
 				MimePart part;
 
 				if (contentType.IsMimeType ("text", "*")) {
@@ -466,7 +480,7 @@ public async Task<MimeEntity> AddAsync (string fileName, Stream stream, ContentT
 			if (contentType is null)
 				throw new ArgumentNullException (nameof (contentType));
 
-			var attachment = await CreateAttachmentAsync (contentType, fileName, stream, true, cancellationToken).ConfigureAwait (false);
+			var attachment = await CreateAttachmentAsync (contentType, false, fileName, stream, true, cancellationToken).ConfigureAwait (false);
 
 			attachments.Add (attachment);
 
@@ -589,7 +603,7 @@ public async Task<MimeEntity> AddAsync (string fileName, Stream stream, Cancella
 			if (stream is null)
 				throw new ArgumentNullException (nameof (stream));
 
-			var attachment = await CreateAttachmentAsync (GetMimeType (fileName), fileName, stream, true, cancellationToken).ConfigureAwait (false);
+			var attachment = await CreateAttachmentAsync (GetMimeType (fileName), true, fileName, stream, true, cancellationToken).ConfigureAwait (false);
 
 			attachments.Add (attachment);
 
@@ -692,7 +706,7 @@ public async Task<MimeEntity> AddAsync (string fileName, ContentType contentType
 				throw new ArgumentNullException (nameof (contentType));
 
 			using (var stream = File.OpenRead (fileName)) {
-				var attachment = await CreateAttachmentAsync (contentType, fileName, stream, true, cancellationToken).ConfigureAwait (false);
+				var attachment = await CreateAttachmentAsync (contentType, false, fileName, stream, true, cancellationToken).ConfigureAwait (false);
 
 				attachments.Add (attachment);
 
@@ -791,7 +805,7 @@ public async Task<MimeEntity> AddAsync (string fileName, CancellationToken cance
 				throw new ArgumentException ("The specified file path is empty.", nameof (fileName));
 
 			using (var stream = File.OpenRead (fileName)) {
-				var attachment = await CreateAttachmentAsync (GetMimeType (fileName), fileName, stream, true, cancellationToken).ConfigureAwait (false);
+				var attachment = await CreateAttachmentAsync (GetMimeType (fileName), true, fileName, stream, true, cancellationToken).ConfigureAwait (false);
 
 				attachments.Add (attachment);
 

diff --git a/UnitTests/AttachmentCollectionTests.cs b/UnitTests/AttachmentCollectionTests.cs
@@ -515,6 +515,54 @@ public async Task TestAddEmailMessageAsync ()
 			attachments.Clear (true);
 		}
 
+		[Test]
+		public void TestAddEmailMessageFallback ()
+		{
+			var fileName = Path.Combine (TestHelper.ProjectDir, "TestData", "images", "girl.jpg");
+			var attachments = new AttachmentCollection ();
+			MimeEntity attachment;
+
+			using (var stream = File.OpenRead (fileName))
+				attachment = attachments.Add ("message.eml", stream);
+
+			Assert.That (attachment.ContentType.MimeType, Is.EqualTo ("application/octet-stream"));
+			Assert.That (attachment.ContentType.Name, Is.EqualTo ("message.eml"));
+			Assert.That (attachment.ContentDisposition, Is.Not.Null);
+			Assert.That (attachment.ContentDisposition.Disposition, Is.EqualTo ("attachment"));
+			Assert.That (attachment.ContentDisposition.FileName, Is.EqualTo ("message.eml"));
+			Assert.That (attachments.Count, Is.EqualTo (1));
+
+			Assert.That (attachments.Contains (attachment), Is.True, "Contains");
+			Assert.That (attachments.IndexOf (attachment), Is.EqualTo (0), "IndexOf");
+			Assert.That (attachments.Remove (attachment), Is.True, "Remove");
+			Assert.That (attachments.Count, Is.EqualTo (0));
+			attachments.Clear (true);
+		}
+
+		[Test]
+		public async Task TestAddEmailMessageFallbackAsync ()
+		{
+			var fileName = Path.Combine (TestHelper.ProjectDir, "TestData", "images", "girl.jpg");
+			var attachments = new AttachmentCollection ();
+			MimeEntity attachment;
+
+			using (var stream = File.OpenRead (fileName))
+				attachment = await attachments.AddAsync ("message.eml", stream);
+
+			Assert.That (attachment.ContentType.MimeType, Is.EqualTo ("application/octet-stream"));
+			Assert.That (attachment.ContentType.Name, Is.EqualTo ("message.eml"));
+			Assert.That (attachment.ContentDisposition, Is.Not.Null);
+			Assert.That (attachment.ContentDisposition.Disposition, Is.EqualTo ("attachment"));
+			Assert.That (attachment.ContentDisposition.FileName, Is.EqualTo ("message.eml"));
+			Assert.That (attachments.Count, Is.EqualTo (1));
+
+			Assert.That (attachments.Contains (attachment), Is.True, "Contains");
+			Assert.That (attachments.IndexOf (attachment), Is.EqualTo (0), "IndexOf");
+			Assert.That (attachments.Remove (attachment), Is.True, "Remove");
+			Assert.That (attachments.Count, Is.EqualTo (0));
+			attachments.Clear (true);
+		}
+
 		[Test]
 		public void TestAddInlineEmailMessage ()
 		{