c# - MailKit SearchQuery.FromContains("")

Question

I am writing a little spams deletion tool for myself. This includes spams where the "FROM" field is empty. Unfortunately, when I try to enter a definition to search by an empty string

SearchQuery.FromContains("")

, I get an error saying that the string cannot be empty.

Anybody have any ideas on this? How can I filter emails based on an empty "TO" or "FROM" field?

Best regards Cezary

question from:https://stackoverflow.com/questions/65897971/mailkit-searchquery-fromcontains

Answer 1

The IMAP SEARCH command is the wrong approach for this, unfortunately, because a search for an empty string will match everything (not just messages with an empty From header or an empty From address).

The best way to do this would be something more like this:

var messages = folder.Fetch (0, -1, MessageSummaryItems.Envelope | MessageSummaryItems.UniqueId);
var spamUids = new UniqueIdSet ();
foreach (var message in messages) {
    if (message.Envelope?.From.Count == 0) {
        // This means there are 0 addresses in the From header
        spamUids.Add (message.UniqueId);
        continue;
    }

    if (message.Envelope?.To.Count == 0) {
        // This means there are 0 addresses in the To header
        spamUids.Add (message.UniqueId);
        continue;
    }
}