SMTP: fix 3024482, avoid duplicate messages with gmail

git-svn-id: http://svn.code.sf.net/p/davmail/code/trunk@1228 3d1905a2-6b24-0410-a738-b14d5a86fcbd

src/java/davmail/exchange/ExchangeSession.java

@@ -194,6 +194,7 @@ public abstract class ExchangeSession {
 
     /**
      * Return standard zulu date formatter.
+     *
      * @return zulu date formatter
      */
     public static SimpleDateFormat getZuluDateFormat() {
@@ -917,6 +918,11 @@ public abstract class ExchangeSession {
      * @throws MessagingException on error
      */
     public void sendMessage(List<String> rcptToRecipients, MimeMessage mimeMessage) throws IOException, MessagingException {
+        // check Sent folder for duplicates
+        ExchangeSession.MessageList messages = searchMessages(SENT, headerEquals("message-id", mimeMessage.getMessageID()));
+        if (!messages.isEmpty()) {
+            LOGGER.debug("Dropping message: already sent");
+        } else {
             // Exchange 2007 : skip From: header
             mimeMessage.removeHeader("from");
 
@@ -936,6 +942,7 @@ public abstract class ExchangeSession {
 
             sendMessage(baos.toByteArray());
         }
+    }
 
     /**
      * Get folder object.

src/test/davmail/smtp/TestSmtp.java

@@ -148,6 +148,16 @@ public class TestSmtp extends AbstractDavMailTestCase {
         sendAndCheckMessage(mimeMessage);
     }
 
+    public void testSendMessageTwice() throws IOException, MessagingException, InterruptedException {
+        String body = "First line\r\n.\r\nSecond line";
+        MimeMessage mimeMessage = new MimeMessage((Session) null);
+        mimeMessage.addHeader("to", Settings.getProperty("davmail.to"));
+        mimeMessage.setSubject("Test subject");
+        mimeMessage.setText(body);
+        sendAndCheckMessage(mimeMessage);
+        sendAndCheckMessage(mimeMessage);
+    }
+
     public void testQuit() throws IOException {
        writeLine("QUIT");
         assertEquals("221 Closing connection", readLine());