Saving attachments using the MailKit library?

Question

I am trying to learn how to use the MailKit library, but I am trying to get attachments. While my code opens the mailbox, look at each message and save the data, such as sender, subject, body, date, etc., but I can not deal with attachments.

I tried to use other people's solutions found here on github and other sites, but I still don’t understand what they are doing in my code, and when I get closer to working with the solution, it causes more errors. I get stress and delete all the code. I do not want to seem lazy, but I would like someone to explain how I can achieve this. I am mainly trying to create an email client for a web forms application.

Below is my code, as you can see that I'm pretty clueless :)

// Open the Inbox folder client.Inbox.Open(FolderAccess.ReadOnly, cancel.Token); //get the full summary information to retrieve all details var summary = client.Inbox.Fetch(0, -1, MessageSummaryItems.Full, cancel.Token); foreach (var msg in summary) { //this code originally downloaded just the text from the body var text = msg.Body as BodyPartText; //but I tried altering it so that it will get attachments here also var attachments = msg.Body as BodyPartBasic; if (text == null) { var multipart = msg.Body as BodyPartMultipart; if (multipart != null) { text = multipart.BodyParts.OfType<BodyPartText>().FirstOrDefault(); } } if (text == null) continue; //I hoped this would get the messages where the content dispositon was not null //and let me do something like save the attachments somewhere but instead it throws exceptions //about the object reference not set to an instance of the object so it very wrong if (attachments.ContentDisposition != null && attachments.ContentDisposition.IsAttachment) { //I tried to do the same as I did with the text here and grab the body part....... but no var attachedpart = client.Inbox.GetBodyPart(msg.Index, attachments, cancel.Token); } else { //there is no plan b :( } // this will download *just* the text var part = client.Inbox.GetBodyPart(msg.Index, text, cancel.Token); //cast main body text to Text Part TextPart _body = (TextPart)part; 

Answer 1

I don’t quite understand what you want to accomplish, but if you just want to download message attachments (without downloading the whole message) and save these attachments in the file system, here is how you can do it:

 var messages = client.Inbox.Fetch (0, -1, MessageSummaryItems.Full | MessageSummaryItems.UniqueId); int unnamed = 0; foreach (var message in messages) { var multipart = message.Body as BodyPartMultipart; var basic = message.Body as BodyPartBasic; if (multipart != null) { foreach (var attachment in multipart.BodyParts.OfType<BodyPartBasic> ().Where (x => x.IsAttachment)) { var mime = (MimePart) client.Inbox.GetBodyPart (message.UniqueId.Value, attachment); var fileName = mime.FileName; if (string.IsNullOrEmpty (fileName)) fileName = string.Format ("unnamed-{0}", ++unnamed); using (var stream = File.Create (fileName)) mime.ContentObject.DecodeTo (stream); } } else if (basic != null && basic.IsAttachment) { var mime = (MimePart) client.Inbox.GetBodyPart (message.UniqueId.Value, basic); var fileName = mime.FileName; if (string.IsNullOrEmpty (fileName)) fileName = string.Format ("unnamed-{0}", ++unnamed); using (var stream = File.Create (fileName)) mime.ContentObject.DecodeTo (stream); } } 

Answer 2

Another alternative that works for me, but looks a bit simpler:

 var messages = client.Inbox.Fetch (0, -1, MessageSummaryItems.Full | MessageSummaryItems.BodyStructure | MessageSummaryItems.UniqueId); int unnamed = 0; foreach (var message in messages) { foreach (var attachment in message.Attachments) { var mime = (MimePart) client.Inbox.GetBodyPart (message.UniqueId.Value, attachment); var fileName = mime.FileName; if (string.IsNullOrEmpty (fileName)) fileName = string.Format ("unnamed-{0}", ++unnamed); using (var stream = File.Create (fileName)) mime.ContentObject.DecodeTo (stream); } } 

Note that this asks for BODYSTRUCTURE instead of BODY in the Fetch statement, which seems to fix the problem of attachments that are not marked as such.