From 88b35117aee79417a5e2e8c30b25e67fa54efbe8 Mon Sep 17 00:00:00 2001
From: Mike Varga <mvarga6@kent.edu>
Date: Fri, 14 Oct 2022 13:49:59 -0400
Subject: [PATCH] Implement read-only mail fetching

---
 django_mailbox/transports/generic.py |  3 ++
 django_mailbox/transports/imap.py    | 45 ++++++++++++++++++++++------
 django_mailbox/transports/pop3.py    |  3 ++
 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/django_mailbox/transports/generic.py b/django_mailbox/transports/generic.py
index 5832fda..2d27fba 100644
--- a/django_mailbox/transports/generic.py
+++ b/django_mailbox/transports/generic.py
@@ -24,3 +24,6 @@ class GenericFileMailbox(EmailTransport):
             yield message
         repository.flush()
         repository.unlock()
+
+    def get_new_message_ro(self, since=None):
+        raise NotImplementedError("GenericFileMailbox.get_new_message_ro not implemented!")
diff --git a/django_mailbox/transports/imap.py b/django_mailbox/transports/imap.py
index 2599ada..79d5b49 100644
--- a/django_mailbox/transports/imap.py
+++ b/django_mailbox/transports/imap.py
@@ -99,19 +99,47 @@ class ImapTransport(EmailTransport):
         if not message_ids:
             return
 
-        # Limit the uids to the small ones if we care about that
-        if self.max_message_size:
-            message_ids = self._get_small_message_ids(message_ids)
-
         if self.archive:
             typ, folders = self.server.list(pattern=self.archive)
             if folders[0] is None:
                 # If the archive folder does not exist, create it
                 self.server.create(self.archive)
 
+        for message in self._iter_messages(message_ids):
+            yield message
+
+        self.server.expunge()
+        return
+
+    def get_new_message_ro(self, since):
+        """Read-only version of `get_message`. Uses a timestamp to fetch only messages
+        originating later than `since` parameter.
+        """
+
+        date_format = "%d-%b-%Y"
+        typ, [raw_msg_ids] = self.server.search(None, '(since "%s")' % (since.strftime(date_format)))
+
+        message_ids = raw_msg_ids.decode().split()
+
+        if not message_ids:
+            return
+
+        for message in self._iter_messages(message_ids, archive=False, delete=False):
+            yield message
+
+        self.server.expunge()
+        return
+
+
+    def _iter_messages(self, message_ids, condition=None, archive=True, delete=True):
+
+        # Limit the uids to the small ones if we care about that
+        if self.max_message_size:
+            message_ids = self._get_small_message_ids(message_ids)
+
         for uid in message_ids:
             try:
-                typ, msg_contents = self.server.uid('fetch', uid, '(RFC822)')
+                typ, msg_contents = self.server.fetch(uid, '(RFC822)')
                 if not msg_contents:
                     continue
                 try:
@@ -129,9 +157,8 @@ class ImapTransport(EmailTransport):
             except MessageParseError:
                 continue
 
-            if self.archive:
+            if archive and self.archive:
                 self.server.uid('copy', uid, self.archive)
 
-            self.server.uid('store', uid, "+FLAGS", "(\\Deleted)")
-        self.server.expunge()
-        return
+            if delete:
+                self.server.uid('store', uid, "+FLAGS", "(\\Deleted)")
\ No newline at end of file
diff --git a/django_mailbox/transports/pop3.py b/django_mailbox/transports/pop3.py
index 6dbe995..3c861f0 100644
--- a/django_mailbox/transports/pop3.py
+++ b/django_mailbox/transports/pop3.py
@@ -42,3 +42,6 @@ class Pop3Transport(EmailTransport):
             self.server.dele(i + 1)
         self.server.quit()
         return
+
+    def get_new_message_ro(self, since=None):
+        raise NotImplementedError("Pop3Transport.get_new_message_ro not implemented!")
\ No newline at end of file