Refactor Message to use Python properties

lib/nntp/tiny/message.py

@@ -43,6 +43,7 @@ class MessageState(enum.Enum):
 
 class Message(DatabaseTable):
     __slots__ = (
+        '_cache',
         'id',
         'newsgroup_id',
         'state',
@@ -68,10 +69,11 @@ class Message(DatabaseTable):
     RE_HEADER = re.compile(r'^([A-Za-z0-9\-]+): (.*)$')
 
     def __init__(self):
+        self._cache       = dict()
         self.id           = None
         self.newsgroup_id = None
         self.state        = MessageState.EMPTY
-        self.headers      = dict()
+        self.headers      = None
         self.line         = None
         self.content      = ''
         self.body         = None
@@ -80,7 +82,14 @@ class Message(DatabaseTable):
     @staticmethod
     def __from_row__(row):
         message = Message()
-        message.id = row['id']
+        message.headers      = dict()
+        message.id           = row['id']
+        message.newsgroup_id = row['newsgroup_id']
+        message.created_on   = row['created_on']
+        message.message_id   = row['message_id']
+        message.parent_id    = row['parent_id']
+        message.sender       = row['sender']
+
         message.read(row['content'])
 
         return message
@@ -88,35 +97,76 @@ class Message(DatabaseTable):
     def __values__(self) -> tuple:
         return (
             self.newsgroup_id,
-            self.date(),
-            self.unique_id(),
-            self.header('references'),
-            self.sender(),
-            self.subject(),
+            self.created_on,
+            self.message_id,
+            self.parent_id,
+            self.sender,
+            self.subject,
             self.content
         )
 
     def header(self, key: str):
+        if self.headers is None:
+            self.read(self.content)
+
         return self.headers.get(key.lower())
 
-    def unique_id(self) -> str:
+    @property
+    def created_on(self):
+        try:
+            value = self._cache.get('created_on')
+
+            if value is not None:
+                ret = datetime.datetime.fromisoformat(value)
+            else:
+                value = self.header('Date')
+
+                if value is None:
+                    ret = search_dates(value)[0][1]
+
+                    self._cache['created_on'] = str(ret)
+        except:
+            ret = datetime.datetime.fromtimestamp(0)
+
+        return ret
+
+    @created_on.setter
+    def created_on(self, value):
+        self.headers['date']      = str(value)
+        self._cache['created_on'] = str(value)
+
+    @property
+    def message_id(self) -> str:
         return self.header('Message-ID')
 
+    @message_id.setter
+    def message_id(self, value):
+        self.headers['message-id'] = value
+
+    @property
     def parent_id(self) -> str:
         return self.header('References')
 
-    def date(self):
-        try:
-            return search_dates(self.headers['date'])[0][1]
-        except:
-            return datetime.datetime.fromtimestamp(0)
+    @parent_id.setter
+    def parent_id(self, value):
+        self.headers['references'] = value
 
-    def sender(self):
+    @property
+    def sender(self) -> str:
         return self.headers.get('from', 'Unknown')
 
-    def subject(self):
+    @sender.setter
+    def sender(self, value):
+        self.headers['from'] = value
+
+    @property
+    def subject(self) -> str:
         return self.headers.get('subject', '(no subject)')
 
+    @subject.setter
+    def subject(self, value):
+        self.headers['subject'] = value
+
     def is_first_line(self):
         return len(self.headers) == 1 and (self.body == '' or self.body is None)
 
@@ -125,7 +175,8 @@ class Message(DatabaseTable):
             self.content += self.line
 
         if self.state is MessageState.EMPTY:
-            self.state = MessageState.HEADER
+            self.state   = MessageState.HEADER
+            self.headers = dict()
 
         if self.state is MessageState.HEADER:
             if line == '\n' or line == '\r\n':