75.2 IMAP: новый сервер на Reactor Netty (STARTTLS, 993, IDLE, UIDPLUS, MOVE)

Старый IMAP (выключен, .block() на сетевом потоке) удалён, написан заново:
- ImapServer: декодер целых команд с литералами ({n} после "+ Ready", {n+}),
  команды по одной на рабочем потоке; STARTTLS (без выполнения открытого текста
  после него) и неявный TLS; IDLE с опросом раз в 5 с до DONE
- ImapSession: IMAP4rev1 + LITERAL+, SASL-IR, IDLE, UIDPLUS, MOVE, UNSELECT,
  NAMESPACE, SPECIAL-USE, ID; FETCH (ENVELOPE, BODYSTRUCTURE, BODY[section]<partial>),
  SEARCH, STORE, COPY/MOVE с COPYUID, APPEND с APPENDUID, EXPUNGE/UID EXPUNGE
- MimeTree: части письма по байтам — размеры BODYSTRUCTURE совпадают с BODY[]
- V4: UID на папку выдаёт триггер (перенос из веба тоже получает новый UID),
  флаги \Answered/\Deleted, message_sources — письмо как пришло (SMTP, APPEND)
  или собранное один раз (MimeSource); правка черновика сбрасывает его
- тесты: настоящий клиент Angus IMAP, сырые литералы/IDLE/подмешивание (47 всего)
- живая проверка: обновление V3 -> V4 на PostgreSQL с письмами, Python imaplib:
  STARTTLS, 993, папки, вложения, поиск, APPEND/COPY/MOVE/EXPUNGE, IDLE — 0 ошибок

α
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

backend/src/main/java/com/mailserver/service/LocalDelivery.java

@@ -38,9 +38,12 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
     private final SpfService spfService;
     private final DmarcService dmarcService;
     private final String hostname;
+    private final MessageSources sources;
 
     public LocalDelivery(MailService mailService, DkimService dkimService, SpfService spfService,
-                         DmarcService dmarcService, @Value("${mailserver.smtp.hostname:localhost}") String hostname) {
+                         DmarcService dmarcService, @Value("${mailserver.smtp.hostname:localhost}") String hostname,
+                         MessageSources sources) {
+        this.sources = sources;
         this.mailService = mailService;
         this.dkimService = dkimService;
         this.spfService = spfService;
@@ -82,11 +85,13 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
             for (FilePart file : attachments(mime)) {
                 mailService.storeIncomingAttachment(stored.getId(), file.name(), file.contentType(), file.bytes());
             }
+            // IMAP serves the message exactly as it arrived
+            sources.put(stored.getId(), raw).block();
         }
     }
 
     /** "a@x, b@y" from a header, or null. A broken header is ignored, not a reason to lose the message. */
-    static String addresses(MimeMessage mime, jakarta.mail.Message.RecipientType type) {
+    public static String addresses(MimeMessage mime, jakarta.mail.Message.RecipientType type) {
         try {
             jakarta.mail.Address[] list = mime.getRecipients(type);
             if (list == null || list.length == 0) {
@@ -103,11 +108,11 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
         }
     }
 
-    record FilePart(String name, String contentType, byte[] bytes) {
+    public record FilePart(String name, String contentType, byte[] bytes) {
     }
 
     /** Parts with a file name (attachments and inline images), nested multiparts walked. */
-    static List<FilePart> attachments(Part part) throws MessagingException, IOException {
+    public static List<FilePart> attachments(Part part) throws MessagingException, IOException {
         List<FilePart> files = new ArrayList<>();
         collect(part, files);
         return files;
@@ -144,11 +149,11 @@ public class LocalDelivery implements DeliveryWorker.BounceSender {
         }
     }
 
-    record Body(String text, boolean html) {
+    public record Body(String text, boolean html) {
     }
 
     /** HTML part when the message has one, otherwise the plain text; nested multiparts are walked. */
-    static Body body(Part part) throws MessagingException, IOException {
+    public static Body body(Part part) throws MessagingException, IOException {
         String html = find(part, "text/html");
         if (html != null) {
             return new Body(html, true);

backend/src/main/java/com/mailserver/service/MailService.java

@@ -59,7 +59,8 @@ public class MailService {
     public MailService(MessageRepository messageRepository, FolderRepository folderRepository,
                        UserRepository userRepository, AttachmentRepository attachmentRepository,
                        ContactRepository contactRepository,
-                       SpamFilterService spamFilterService) {
+                       SpamFilterService spamFilterService, MessageSources sources) {
+        this.sources = sources;
         this.messageRepository = messageRepository;
         this.folderRepository = folderRepository;
         this.userRepository = userRepository;
@@ -69,6 +70,8 @@ public class MailService {
     }
 
     /** System folders in the order the web client shows them; the rest — own folders, by name. */
+    private final MessageSources sources;
+
     public static final List<String> SYSTEM_FOLDERS = List.of("INBOX", "Drafts", "Sent", "Spam", "Trash");
 
     /** Messages per folder in one list — the web client sorts and pages them itself. */
@@ -212,6 +215,8 @@ public class MailService {
                     message.setMessageSize((long) (subject.length() + body.length()));
                     return messageRepository.save(message);
                 })
+                // IMAP: the draft changed — its MIME text is built anew
+                .flatMap(saved -> sources.remove(saved.getId()).thenReturn(saved))
                 .flatMap(this::withAttachmentCount);
     }
 
@@ -226,6 +231,7 @@ public class MailService {
     /** After sending: the draft's attachments move to the copy in Sent, the draft itself is removed. */
     public Mono<Void> finishDraft(Long draftId, Long sentMessageId) {
         return attachmentRepository.moveAll(draftId, sentMessageId)
+                .then(sources.remove(sentMessageId))
                 .then(messageRepository.deleteById(draftId));
     }
 
@@ -467,7 +473,7 @@ public class MailService {
                     attachment.setContentType(contentType);
                     attachment.setSizeBytes(sizeBytes);
                     attachment.setFilePath(filePath);
-                    return attachmentRepository.save(attachment);
+                    return sources.remove(messageId).then(attachmentRepository.save(attachment));
                 })
                 .map(this::toAttachmentResponse);
     }
@@ -491,7 +497,7 @@ public class MailService {
         return ownedAttachment(attachmentId, userId)
                 .flatMap(attachment -> {
                     deleteFile(attachment.getFilePath());
-                    return attachmentRepository.delete(attachment);
+                    return sources.remove(attachment.getMessageId()).then(attachmentRepository.delete(attachment));
                 });
     }
 

backend/src/main/java/com/mailserver/service/MessageSources.java

@@ -0,0 +1,38 @@
+package com.mailserver.service;
+
+import org.springframework.r2dbc.core.DatabaseClient;
+import org.springframework.stereotype.Component;
+import reactor.core.publisher.Mono;
+
+/**
+ * The message exactly as received or appended (table message_sources). IMAP serves it as BODY[]; a message without
+ * one gets its MIME text built once ({@link com.mailserver.imap.MimeSource}). A changed draft loses it.
+ */
+@Component
+public class MessageSources {
+
+    private final DatabaseClient db;
+
+    public MessageSources(DatabaseClient db) {
+        this.db = db;
+    }
+
+    public Mono<byte[]> get(Long messageId) {
+        return db.sql("SELECT raw FROM message_sources WHERE message_id = :id")
+                .bind("id", messageId)
+                .map(row -> row.get("raw", byte[].class))
+                .one();
+    }
+
+    public Mono<Void> put(Long messageId, byte[] raw) {
+        return db.sql("INSERT INTO message_sources (message_id, raw) VALUES (:id, :raw) "
+                        + "ON CONFLICT (message_id) DO UPDATE SET raw = EXCLUDED.raw")
+                .bind("id", messageId)
+                .bind("raw", raw)
+                .then();
+    }
+
+    public Mono<Void> remove(Long messageId) {
+        return db.sql("DELETE FROM message_sources WHERE message_id = :id").bind("id", messageId).then();
+    }
+}