Load past events when scrolling up

Also keep two nio clients internally: one for loop-syncing, one for the
rest; since they can't handle more than one talk at a time.

TODO.md

@@ -17,8 +17,6 @@
 - Use Loader? for MessageDelegate to show sub-components based on condition
 - Better names and organization for the Message components
 
-- Load previous events on scroll up
-
 - Migrate more JS functions to their own files
 
 - Accept room\_id arg for getUser

harmonyqml/backend/backend.py

@@ -15,6 +15,8 @@ from .html_filter import HtmlFilter
 class Backend(QObject):
     def __init__(self) -> None:
         super().__init__()
+        self.past_tokens: Dict[str, str] = {}
+
         self._client_manager: ClientManager = ClientManager()
         self._models:         QMLModels     = QMLModels()
         self._html_filter:    HtmlFilter    = HtmlFilter()
@@ -56,3 +58,16 @@ class Backend(QObject):
       # pylint:disable=no-self-use
         md5 = hashlib.md5(bytes(string, "utf-8")).hexdigest()
         return float("0.%s" % int(md5[-10:], 16))
+
+
+    @pyqtSlot(str)
+    def loadPastEvents(self, room_id: str) -> None:
+        if not room_id in self.past_tokens:
+            return  # Initial sync not done yet
+
+        for client in self.clientManager.clients.values():
+            if room_id in client.nio.rooms:
+                client.loadPastEvents(room_id, self.past_tokens[room_id])
+                break
+        else:
+            raise ValueError(f"Room not found in any client: {room_id}")

harmonyqml/backend/client.py

@@ -14,6 +14,8 @@ from PyQt5.QtCore import QObject, pyqtProperty, pyqtSignal, pyqtSlot
 import nio
 import nio.responses as nr
 
+from .network_manager import NetworkManager
+
 # One pool per hostname/remote server;
 # multiple Client for different accounts on the same server can exist.
 _POOLS: DefaultDict[str, ThreadPoolExecutor] = \
@@ -40,6 +42,8 @@ class Client(QObject):
     roomInvited                    = pyqtSignal(str)
     roomJoined                     = pyqtSignal(str)
     roomLeft                       = pyqtSignal(str)
+    roomSyncPrevBatchTokenReceived = pyqtSignal(str, str)
+    roomPastPrevBatchTokenReceived = pyqtSignal(str, str)
     roomEventReceived              = pyqtSignal(str, str, dict)
     roomTypingUsersUpdated         = pyqtSignal(str, list)
 
@@ -52,13 +56,18 @@ class Client(QObject):
         self.host: str = host
         self.port: int = int(port[0]) if port else 443
 
+        self.pool: ThreadPoolExecutor = _POOLS[self.host]
+
         self.nio: nio.client.HttpClient = \
             nio.client.HttpClient(self.host, username, device_id)
 
-        self.pool: ThreadPoolExecutor = _POOLS[self.host]
+        # Since nio clients can't handle more than one talk operation
+        # at a time, this one is used exclusively to poll the sync API
+        self.nio_sync: nio.client.HttpClient = \
+            nio.client.HttpClient(self.host, username, device_id)
 
-        from .network_manager import NetworkManager
-        self.net: NetworkManager = NetworkManager(self)
+        self.net      = NetworkManager(self.host, self.port, self.nio)
+        self.net_sync = NetworkManager(self.host, self.port, self.nio_sync)
 
         self._stop_sync: Event = Event()
 
@@ -78,7 +87,10 @@ class Client(QObject):
     @futurize
     def login(self, password: str, device_name: str = "") -> None:
         self.net.write(self.nio.connect())
-        self.net.talk(self.nio.login, password, device_name)
+        response = self.net.talk(self.nio.login, password, device_name)
+
+        self.net_sync.write(self.nio_sync.connect())
+        self.nio_sync.receive_response(response)
         self.startSyncing()
 
 
@@ -89,6 +101,9 @@ class Client(QObject):
         self.net.write(self.nio.connect())
         response = nr.LoginResponse(user_id, device_id, token)
         self.nio.receive_response(response)
+
+        self.net_sync.write(self.nio_sync.connect())
+        self.nio_sync.receive_response(response)
         self.startSyncing()
 
 
@@ -97,13 +112,16 @@ class Client(QObject):
     def logout(self) -> None:
         self._stop_sync.set()
         self.net.write(self.nio.disconnect())
+        self.net_sync.write(self.nio_sync.disconnect())
 
 
     @pyqtSlot()
     @futurize
     def startSyncing(self) -> None:
         while True:
-            self._on_sync(self.net.talk(self.nio.sync, timeout=10_000))
+            self._on_sync(self.net_sync.talk(
+                self.nio_sync.sync, timeout=10_000
+            ))
 
             if self._stop_sync.is_set():
                 self._stop_sync.clear()
@@ -111,12 +129,18 @@ class Client(QObject):
 
 
     def _on_sync(self, response: nr.SyncResponse) -> None:
+        self.nio.receive_response(response)
+
         for room_id in response.rooms.invite:
             self.roomInvited.emit(room_id)
 
         for room_id, room_info in response.rooms.join.items():
             self.roomJoined.emit(room_id)
 
+            self.roomSyncPrevBatchTokenReceived.emit(
+                room_id, room_info.timeline.prev_batch
+            )
+
             for ev in room_info.timeline.events:
                 self.roomEventReceived.emit(
                     room_id, type(ev).__name__, ev.__dict__
@@ -130,3 +154,24 @@ class Client(QObject):
 
         for room_id in response.rooms.leave:
             self.roomLeft.emit(room_id)
+
+
+    @futurize
+    def loadPastEvents(self, room_id: str, start_token: str) -> None:
+        # From QML, use Backend.loastPastEvents instead
+        self._on_past_events(
+            room_id,
+            self.net.talk(
+                self.nio.room_messages, room_id, start=start_token, limit=100
+            )
+        )
+
+
+    def _on_past_events(self, room_id: str, response: nr.RoomMessagesResponse
+                       ) -> None:
+        self.roomPastPrevBatchTokenReceived.emit(room_id, response.end)
+
+        for ev in response.chunk:
+            self.roomEventReceived.emit(
+                room_id, type(ev).__name__, ev.__dict__
+            )

harmonyqml/backend/html_filter.py

@@ -41,11 +41,11 @@ class HtmlFilter(QObject):
     @pyqtSlot(str, result=str)
     def filter(self, html: str) -> str:
         html = self._sanitizer.sanitize(html)
-        if not html:
-            return ""
-
         tree = etree.fromstring(html, parser=etree.HTMLParser())
 
+        if tree is None:
+            return ""
+
         for el in tree.iter("img"):
             el = self._wrap_img_in_a(el)
 

harmonyqml/backend/network_manager.py

@@ -5,13 +5,13 @@ import logging
 import socket
 import ssl
 import time
+from threading import Lock
 from typing import Callable, Optional, Tuple
 from uuid import UUID
 
+import nio
 import nio.responses as nr
 
-from .client import Client
-
 OptSock        = Optional[ssl.SSLSocket]
 NioRequestFunc = Callable[..., Tuple[UUID, bytes]]
 
@@ -26,16 +26,21 @@ class NetworkManager:
     http_retry_codes = {408, 429, 500, 502, 503, 504, 507}
 
 
-    def __init__(self, client: Client) -> None:
-        self.client = client
+    def __init__(self, host: str, port: int, nio_client: nio.client.HttpClient
+                ) -> None:
+        self.host = host
+        self.port = port
+        self.nio  = nio_client
+
         self._ssl_context: ssl.SSLContext = ssl.create_default_context()
         self._ssl_session: Optional[ssl.SSLSession] = None
+        self._lock: Lock = Lock()
 
 
     def _get_socket(self) -> ssl.SSLSocket:
         sock = self._ssl_context.wrap_socket(  # type: ignore
-            socket.create_connection((self.client.host, self.client.port)),
-            server_hostname = self.client.host,
+            socket.create_connection((self.host, self.port)),
+            server_hostname = self.host,
             session         = self._ssl_session,
         )
         self._ssl_session = self._ssl_session or sock.session
@@ -53,8 +58,12 @@ class NetworkManager:
 
         response = None
         while not response:
-            self.client.nio.receive(sock.recv(4096))
-            response = self.client.nio.next_response()
+            left_to_send = self.nio.data_to_send()
+            if left_to_send:
+                self.write(left_to_send, sock)
+
+            self.nio.receive(sock.recv(4096))
+            response = self.nio.next_response()
 
         if isinstance(response, nr.ErrorResponse):
             raise NioErrorResponse(response)
@@ -66,6 +75,9 @@ class NetworkManager:
 
 
     def write(self, data: bytes, with_sock: OptSock = None) -> None:
+        if not data:
+            return
+
         sock = with_sock or self._get_socket()
         sock.sendall(data)
 
@@ -74,6 +86,7 @@ class NetworkManager:
 
 
     def talk(self, nio_func: NioRequestFunc, *args, **kwargs) -> nr.Response:
+        with self._lock:
             while True:
                 to_send = nio_func(*args, **kwargs)[1]
                 sock    = self._get_socket()
@@ -83,7 +96,7 @@ class NetworkManager:
                     response = self.read(sock)
 
                 except NioErrorResponse as err:
-                logging.error("read bad response for %s: %s", nio_func, err)
+                    logging.error("bad read for %s: %s", nio_func, err)
                     self._close_socket(sock)
 
                     if self._should_abort_talk(err):

harmonyqml/backend/signal_manager.py

@@ -81,6 +81,21 @@ class SignalManager(QObject):
         del rooms[rooms.indexWhere("room_id", room_id)]
 
 
+    def onRoomSyncPrevBatchTokenReceived(
+            self, _: Client, room_id: str, token: str
+        ) -> None:
+
+        if room_id not in self.backend.past_tokens:
+            self.backend.past_tokens[room_id] = token
+
+
+    def onRoomPastPrevBatchTokenReceived(
+            self, _: Client, room_id: str, token: str
+        ) -> None:
+
+        self.backend.past_tokens[room_id] = token
+
+
     def onRoomEventReceived(
             self, _: Client, room_id: str, etype: str, edict: Dict[str, Any]
         ) -> None:

harmonyqml/components/chat/MessageList.qml

@@ -26,14 +26,8 @@ Rectangle {
         // reloaded from network.
         cacheBuffer: height * 6
 
-        function goToEnd() {
-            messageListView.positionViewAtEnd()
-            //messageListView.flick(0, -messageListView.bottomMargin * 100)
+        onMovementEnded: if (atYBeginning) {
+            Backend.loadPastEvents(chatPage.room.room_id)
         }
-
-        //Connections {
-            //target: messageListView.model
-            //onChanged: goToEnd()
-        //}
     }
 }