Can we add Custom Headers to the received mails through IMAP?

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asked May 31 by Saranyan (120 points)

We want to add a Custom Header to each received email and archive it using imap. We want to know,whether we can do this using Rebex IMAP. We are planning to purchase the software.

Applies to: Rebex Secure Mail

1 Answer

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answered Jun 1 by Lukas Pokorny (109,670 points)

The IMAP protocol doesn't make it possible to modify a message at the IMAP server. However, you can download the message, modify it, and then optionally re-upload it (in case you would like to archive it on the IMAP server).

For information on how to download messages, please see IMAP - message operations and check out the ImapDownloader sample that comes with Rebex Secure Mail install package.

To add a header to a downloaded message, the most efficient method would be to use the low-level MimeMessage class with OnlyParseHeaders option:

var message = new MimeMessage();
message.Options = MimeOptions.OnlyParseHeaders;
message.Load(path);
message.Headers.Add("X-My-Custom-Header", "Custom header value");
message.Save(path);

(Although, for more complex operations, the high-level MailMessage class is usually more suitable.)

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