Pause download when playback stops

Use the add-on's service to monitor when the playback is stopped.
When it occurs, the download of the torrent is paused to have a
behavior similar to streaming.

To be able to pause the torrent, the service needs to use the
torrent handle. The torrent handle is recreated on the service-side
using the URL that was sent to vfs.libtorrent. This URL is sent to
the service before the playback starts using the AddonSignals.
Calling `xbmcvfs.File()` on existing torrent is fast enough for this
solution to be used even on slow devices.

addon.xml

@@ -9,7 +9,7 @@
   <extension point="xbmc.python.pluginsource" library="main.py">
     <provides>video</provides>
   </extension>
-  <!--<extension point="xbmc.service" library="service.py"/>-->
+  <extension point="xbmc.service" library="service.py"/>
   <extension point="xbmc.addon.metadata">
     <summary lang="de_DE">Add-on für PeerTube</summary>
 	<description lang="de_DE">PeerTube ist eine kostenlose, dezentralisierte und föderierte Alternative zu anderen Videoplattformen (wie YouTube).</description>

resources/language/resource.language.de_de/strings.po

@@ -86,8 +86,8 @@ msgid "PeerTube service started"
 msgstr "PeerTube-Dienst gestartet"
 
 msgctxt "#30401"
-msgid "Torrents can now be downloaded."
+msgid "Torrents can now be controlled."
-msgstr "Torrents können jetzt heruntergeladen werden."
+msgstr ""
 
 msgctxt "#30402"
 msgid "Request error"

resources/language/resource.language.en_gb/strings.po

@@ -86,7 +86,7 @@ msgid "PeerTube service started"
 msgstr ""
 
 msgctxt "#30401"
-msgid "Torrents can now be downloaded."
+msgid "Torrents can now be controlled."
 msgstr ""
 
 msgctxt "#30402"

resources/language/resource.language.fr_fr/strings.po

@@ -86,8 +86,8 @@ msgid "PeerTube service started"
 msgstr "Le service PeerTube a démarré"
 
 msgctxt "#30401"
-msgid "Torrents can now be downloaded."
+msgid "Torrents can now be controlled."
-msgstr "Les torrents peuvent maintenant être téléchargés."
+msgstr "Les torrents peuvent maintenant être contrôlés."
 
 msgctxt "#30402"
 msgid "Request error"

resources/lib/addon.py

@@ -15,6 +15,7 @@ from urllib import quote_plus
 from resources.lib.kodi_utils import kodi
 from resources.lib.peertube import PeerTube, list_instances
 
+import AddonSignals
 import xbmcvfs
 
 class PeerTubeAddon():
@@ -22,9 +23,6 @@ class PeerTubeAddon():
     Main class used by the add-on
     """
 
-    # URL of the page which explains how to install libtorrent
-    HELP_URL = "https://link.infini.fr/libtorrent-peertube-kodi"
-
     def __init__(self):
         """Initialize parameters and create a PeerTube instance"""
 
@@ -40,14 +38,6 @@ class PeerTubeAddon():
         self.torrent_name = ""
         self.torrent_file = ""
 
-        # Check whether libtorrent could be imported by the service. The value
-        # of the associated property is retrieved only once and stored in an
-        # attribute because libtorrent is imported only once at the beginning
-        # of the service (we assume it is not possible to start the add-on
-        # before the service)
-        self.libtorrent_imported = \
-            kodi.get_property("libtorrent_imported") == "True"
-
         # Create a PeerTube object to send requests: settings which are used
         # only by this object are directly retrieved from the settings
         self.peertube = PeerTube(
@@ -349,6 +339,8 @@ class PeerTubeAddon():
         vfs_url = "torrent://{}".format(quote_plus(torrent_url))
         torrent = xbmcvfs.File(vfs_url)
 
+        AddonSignals.sendSignal("get_torrent", {"torrent_url": vfs_url})
+
         # Download the file
         if(torrent.write("download")):
 
@@ -366,6 +358,7 @@ class PeerTubeAddon():
             # Play the file
             kodi.debug("Starting video playback of {}".format(self.torrent_file))
             kodi.play(self.torrent_file)
+
         else:
             kodi.notif_error(title=kodi.get_string(30421),
                              message=kodi.get_string(30422))

service.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 """
-    PeerTube service to download torrents in the background
+    PeerTube service to perform action on torrents in background
 
     Copyright (C) 2018 Cyrille Bollu
     Copyright (C) 2021 Thomas Bétous
@@ -8,73 +8,36 @@
     SPDX-License-Identifier: GPL-3.0-only
     See LICENSE.txt for more information.
 """
-
+import AddonSignals
-import AddonSignals # Module exists only in Kodi - pylint: disable=import-error
+import xbmc
-from threading import Thread
+import xbmcvfs
-import xbmc # Kodistubs for Leia is not compatible with python3 / pylint: disable=syntax-error
-import xbmcvfs # Kodistubs for Leia is not compatible with python3 / pylint: disable=syntax-error
 
 from resources.lib.kodi_utils import kodi
 
-class PeertubeDownloader(Thread):
+class PeertubePlayer(xbmc.Player):
-    """
+    # Initialize the attributes and call the parent class constructor
-    A class to download PeerTube torrents in the background
+    def __init__(self):
-    """
+        self.torrent_url = None
+        super(xbmc.Player, self).__init__()
+        # super().__init__()
 
-    def __init__(self, url, temp_dir):
+    # This function will be called through AddonSignals when a video is played.
-        """
+    # It will save the URL expected by vfs.libtorrent to control the torrent. 
-        Initialise a PeertubeDownloader instance for downloading the torrent
+    def receive_torrent(self, data):
-        specified by url
+        self.torrent_url = data["torrent_url"]
+        kodi.debug(message="Received handle:\n{}".format(self.torrent_url), prefix="PeertubePlayer")
 
-        :param url, temp_dir: str
+    # Callback when the playback is stopped. It is used to pause the torrent to
-        :return: None
+    # avoid downloading in background a video which may never be played.
-        """
+    def onPlayBackStopped(self):
-        Thread.__init__(self)
+        if self.torrent_url is not None:
-        self.torrent = url
+            kodi.debug(message="Playback stopped: pausing torrent...", prefix="PeertubePlayer")            
-        self.temp_dir = temp_dir
+            # Get the torrent handle
-
+            torrent = xbmcvfs.File(self.torrent_url)
-    def debug(self, message):
+            # Call seek() to pause the torrent. 0 is used as second argument so
-        """Log a debug message
+            # that GetLength() is not called.
-
+            torrent.seek(0, 0)
-        :param str message: Message to log (will be prefixed with the name of
+            self.torrent_url = None
-        the class)
-        """
-        kodi.debug(message=message, prefix="PeertubeDownloader")
-
-    def run(self):
-        """
-        Download the torrent specified by self.torrent
-        :param: None
-        :return: None
-        """
-
-        self.debug("Opening BitTorent session")
-        # Open BitTorrent session
-        ses = libtorrent.session()
-        ses.listen_on(6881, 6891)
-
-        # Add torrent
-        self.debug("Adding torrent {}".format(self.torrent))
-        h = ses.add_torrent({"url": self.torrent, "save_path": self.temp_dir})
-
-        # Set sequential mode to allow watching while downloading
-        h.set_sequential_download(True)
-
-        # Download torrent
-        self.debug("Downloading torrent {}".format(self.torrent))
-        signal_sent = 0
-        while not h.is_seed():
-            xbmc.sleep(1000)
-            s = h.status()
-            # Inform addon that all the metadata has been downloaded and that
-            # it may start playing the torrent
-            if s.state >=3 and signal_sent == 0:
-                self.debug("Received all torrent metadata, notifying"
-                           " PeertubeAddon")
-                i = h.torrent_file()
-                f = self.temp_dir + i.name()
-                AddonSignals.sendSignal("metadata_downloaded", {"file": f})
-                signal_sent = 1
 
 class PeertubeService():
     """
@@ -83,13 +46,10 @@ class PeertubeService():
 
     def __init__(self):
         """
-        PeertubeService initialisation function
+        Create an instance of PeertubePlayer that will always be active
+        (required to monitor the events and call the callbacks)
         """
-        # Create our temporary directory
+        self.player = PeertubePlayer()
-        self.temp = "{}{}".format(xbmc.translatePath("special://temp"),
-                                  "plugin.video.peertube/")
-        if not xbmcvfs.exists(self.temp):
-            xbmcvfs.mkdir(self.temp)
 
     def debug(self, message):
         """Log a debug message
@@ -99,43 +59,29 @@ class PeertubeService():
         """
         kodi.debug(message=message, prefix="PeertubeService")
 
-    def download_torrent(self, data):
-        """
-        Start a downloader thread to download torrent specified by data["url"]
-        :param data: dict
-        :return: None
-        """
-
-        self.debug("Received a start_download signal")
-        downloader = PeertubeDownloader(data["url"], self.temp)
-        downloader.start()
-
     def run(self):
         """
         Main loop of the PeertubeService class
 
-        It registers the start_download signal to start a PeertubeDownloader
-        thread when needed, and exit when Kodi is shutting down.
         """
 
-        self.debug("Starting")
+        # Signal that is sent by the main script of the add-on
-
-        # Launch the download_torrent callback function when the
-        # "start_download" signal is received
         AddonSignals.registerSlot(kodi.addon_id,
-                                  "start_download",
+                                  "get_torrent",
-                                  self.download_torrent)
+                                  self.player.receive_torrent)
 
-        # Monitor Kodi's shutdown signal
+
-        self.debug("Service started, waiting for signals")
+        # Display a notification now that the service started.
+        self.debug("Service started")
         if kodi.get_setting("service_start_notif") == "true":
             kodi.notif_info(title=kodi.get_string(30400),
                             message=kodi.get_string(30401))
+
+        # Run the service until Kodi exits
         monitor = xbmc.Monitor()
         while not monitor.abortRequested():
             if monitor.waitForAbort(1):
-                # Abort was requested while waiting. We must exit
+                # Abort was requested while waiting. We must exit.
-                # TODO: Clean temporary directory
                 self.debug("Exiting")
                 break
 
@@ -143,18 +89,5 @@ if __name__ == "__main__":
     # Create a PeertubeService instance
     service = PeertubeService()
 
-    # Import libtorrent here to manage when the library is not installed
-    try:
-        from python_libtorrent import libtorrent
-        LIBTORRENT_IMPORTED = True
-    except ImportError as exception:
-        LIBTORRENT_IMPORTED = False
-        service.debug("The libtorrent library could not be imported because of"
-                      " the following error:\n{}".format(exception))
-
-    # Save whether libtorrent could be imported as a window property so that
-    # this information can be retrieved by the add-on
-    kodi.set_property("libtorrent_imported", str(LIBTORRENT_IMPORTED))
-
     # Start the service
     service.run()