JAMES-5431 add SanitizeMimeMessageId mailet (#2718)

Author: AlaeMghirbi

docs/modules/servers/partials/SanitizeMimeMessageId.adoc

@@ -0,0 +1,28 @@
+=== SanitizeMimeMessageId Mailet
+
+Some email clients, such as Outlook for Android, may send emails **without a `Message-ID` header**.
+
+== Why is this needed?
+ The absence of the `Message-ID` header can cause emails to be rejected by downstream mail servers,
+ as required by RFC 5322 specifications. For example, Gmail rejects messages without this header with
+ an error like the following:
+ 550-5.7.1 [IP] Messages missing a valid Message-ID header are not
+ 550-5.7.1 accepted. For more information, go to
+ 550-5.7.1 https://support.google.com/mail/?p=RfcMessageNonCompliant and review
+ 550 5.7.1 RFC 5322 specifications.
+
+To mitigate this, the `SanitizeMimeMessageId` mailet will automatically add a `Message-ID` to emails **that lack one**.
+
+== Configuration
+
+You can configure it simply by adding the following in your `mailetcontainer.xml` file:
+
+....
+<mailet match="All" class="SanitizeMimeMessageId"/>
+....
+
+== Behavior
+
+- If a `Message-ID` header already exists: nothing is done.
+- If the header is missing: a new one is generated and added.
+

docs/modules/servers/partials/configure/mailets.adoc

@@ -147,4 +147,6 @@ include::partial$UseHeaderRecipients.adoc[]
 
 include::partial$WrapText.adoc[]
 
-include::partial$SubAddressing.adoc[]
+include::partial$SubAddressing.adoc[]
+
+include::partial$SanitizeMimeMessageId.adoc[]

mailet/standard/src/main/java/org/apache/james/transport/mailets/SanitizeMimeMessageId.java

@@ -0,0 +1,52 @@
+/****************************************************************
+ * Licensed to the Apache Software Foundation (ASF) under one   *
+ * or more contributor license agreements.  See the NOTICE file *
+ * distributed with this work for additional information        *
+ * regarding copyright ownership.  The ASF licenses this file   *
+ * to you under the Apache License, Version 2.0 (the            *
+ * "License"); you may not use this file except in compliance   *
+ * with the License.  You may obtain a copy of the License at   *
+ *                                                              *
+ *   http://www.apache.org/licenses/LICENSE-2.0                 *
+ *                                                              *
+ * Unless required by applicable law or agreed to in writing,   *
+ * software distributed under the License is distributed on an  *
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
+ * KIND, either express or implied.  See the License for the    *
+ * specific language governing permissions and limitations      *
+ * under the License.                                           *
+ ****************************************************************/
+
+package org.apache.james.transport.mailets;
+
+import jakarta.mail.MessagingException;
+
+import org.apache.mailet.Mail;
+import org.apache.mailet.base.GenericMailet;
+
+/**
+* The `SanitizeMimeMessageId` mailet is designed to address a specific issue where some email clients, such as Outlook for Android, do not add the MIME `Message-ID` header to the emails they send.
+* The absence of the `Message-ID` header can cause emails to be rejected by downstream mail servers,
+* as required by RFC 5322 specifications.
+*
+* Sample configuration:
+*
+* <pre><code>
+* &lt;mailet match="All" class="SanitizeMimeMessageId"&gt;
+* &lt;/mailet&gt;
+* </code></pre>
+*/
+public class SanitizeMimeMessageId extends GenericMailet {
+
+    @Override
+    public void service(Mail mail) throws MessagingException {
+        if (mail.getMessage().getMessageID() == null) {
+            mail.getMessage().saveChanges();
+        }
+    }
+
+    @Override
+    public String getMailetInfo() {
+        return "SanitizeMimeMessageId Mailet";
+    }
+}

mailet/standard/src/test/java/org/apache/james/transport/mailets/SanitizeMimeMessageIdTest.java

@@ -0,0 +1,72 @@
+/****************************************************************
+ * Licensed to the Apache Software Foundation (ASF) under one   *
+ * or more contributor license agreements.  See the NOTICE file *
+ * distributed with this work for additional information        *
+ * regarding copyright ownership.  The ASF licenses this file   *
+ * to you under the Apache License, Version 2.0 (the            *
+ * "License"); you may not use this file except in compliance   *
+ * with the License.  You may obtain a copy of the License at   *
+ *                                                              *
+ *   http://www.apache.org/licenses/LICENSE-2.0                 *
+ *                                                              *
+ * Unless required by applicable law or agreed to in writing,   *
+ * software distributed under the License is distributed on an  *
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
+ * KIND, either express or implied.  See the License for the    *
+ * specific language governing permissions and limitations      *
+ * under the License.                                           *
+ ****************************************************************/
+package org.apache.james.transport.mailets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Properties;
+
+import jakarta.mail.Session;
+import jakarta.mail.internet.MimeMessage;
+
+import org.apache.mailet.base.test.FakeMail;
+import org.apache.mailet.base.test.FakeMailetConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SanitizeMimeMessageIdTest {
+
+    private SanitizeMimeMessageId testee;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        testee = new SanitizeMimeMessageId();
+        testee.init(FakeMailetConfig.builder()
+            .mailetName("SanitizeMimeMessageId")
+            .build());
+    }
+
+    @Test
+    public void shouldAddMessageIdWhenMissing() throws Exception {
+        MimeMessage mimeMessage = new MimeMessage(Session.getDefaultInstance(new Properties()));
+        FakeMail mail = FakeMail.builder()
+            .name("mail")
+            .mimeMessage(mimeMessage)
+            .build();
+
+        testee.service(mail);
+
+        assertThat(mail.getMessage().getHeader("Message-ID")).isNotNull();
+    }
+
+    @Test
+    public void shouldNotModifyExistingMessageId() throws Exception {
+        MimeMessage mimeMessage = new MimeMessage(Session.getDefaultInstance(new Properties()));
+        mimeMessage.setHeader("Message-ID", "<existing-id@domain.com>");
+        FakeMail mail = FakeMail.builder()
+            .name("mail")
+            .mimeMessage(mimeMessage)
+            .build();
+
+        testee.service(mail);
+
+        assertThat(mail.getMessage().getHeader("Message-ID")).containsExactly("<existing-id@domain.com>");
+    }
+}
+