[fc2:live] Add extractor (#2418)

Authored by: Lesmiscore

yt_dlp/downloader/fc2.py

@@ -0,0 +1,41 @@
+from __future__ import division, unicode_literals
+
+import threading
+
+from .common import FileDownloader
+from .external import FFmpegFD
+
+
+class FC2LiveFD(FileDownloader):
+    """
+    Downloads FC2 live without being stopped. <br>
+    Note, this is not a part of public API, and will be removed without notice.
+    DO NOT USE
+    """
+
+    def real_download(self, filename, info_dict):
+        ws = info_dict['ws']
+
+        heartbeat_lock = threading.Lock()
+        heartbeat_state = [None, 1]
+
+        def heartbeat():
+            try:
+                heartbeat_state[1] += 1
+                ws.send('{"name":"heartbeat","arguments":{},"id":%d}' % heartbeat_state[1])
+            except Exception:
+                self.to_screen('[fc2:live] Heartbeat failed')
+
+            with heartbeat_lock:
+                heartbeat_state[0] = threading.Timer(30, heartbeat)
+                heartbeat_state[0]._daemonic = True
+                heartbeat_state[0].start()
+
+        heartbeat()
+
+        new_info_dict = info_dict.copy()
+        new_info_dict.update({
+            'ws': None,
+            'protocol': 'live_ffmpeg',
+        })
+        return FFmpegFD(self.ydl, self.params or {}).download(filename, new_info_dict)