A bit of thread refactoring

spotdl/command_line/arguments.py

@@ -68,31 +68,37 @@ def get_arguments(argv=None, to_merge=True):
     group.add_argument(
         "-l",
         "--list",
-        help="download tracks from a file"
+        help="download tracks from a file (WARNING: this file will be modified!)"
     )
     group.add_argument(
         "-p",
         "--playlist",
-        help="load tracks from playlist URL into <playlist_name>.txt",
+        help="load tracks from playlist URL into <playlist_name>.txt or "
+             "if `--write-to=<path/to/file.txt>` has been passed",
     )
     group.add_argument(
-        "-b", "--album", help="load tracks from album URL into <album_name>.txt"
+        "-b"
+        "--album",
+        help="load tracks from album URL into <album_name>.txt or if "
+             "`--write-to=<path/to/file.txt>` has been passed"
     )
     group.add_argument(
         "-ab",
         "--all-albums",
-        help="load all tracks from artist URL into <artist_name>.txt",
+        help="load all tracks from artist URL into <artist_name>.txt "
+             "or if `--write-to=<path/to/file.txt>` has been passed"
     )
     group.add_argument(
         "-u",
         "--username",
-        help="load tracks from user's playlist into <playlist_name>.txt",
+        help="load tracks from user's playlist into <playlist_name>.txt "
+             "or if `--write-to=<path/to/file.txt>` has been passed"
     )
 
     parser.add_argument(
         "--write-m3u",
         help="generate an .m3u playlist file with youtube links given "
-            "a text file containing tracks",
+             "a text file containing tracks",
         action="store_true",
     )
     parser.add_argument(
@@ -102,13 +108,6 @@ def get_arguments(argv=None, to_merge=True):
         help="choose the track to download manually from a list of matching tracks",
         action="store_true",
     )
-    parser.add_argument(
-        "-nr",
-        "--no-remove-original",
-        default=config["no-remove-original"],
-        help="do not remove the original file after conversion",
-        action="store_true",
-    )
     parser.add_argument(
         "-nm",
         "--no-metadata",

spotdl/command_line/helpers.py

@@ -1,7 +1,10 @@
 from spotdl.metadata.providers import ProviderSpotify
 from spotdl.metadata.providers import ProviderYouTube
 from spotdl.metadata.embedders import EmbedderDefault
-from spotdl.encode.encoders import EncoderFFmpeg, EncoderAvconv
+
+from spotdl.encode.encoders import EncoderFFmpeg
+from spotdl.encode.encoders import EncoderAvconv
+
 from spotdl.lyrics.providers import LyricWikia
 from spotdl.lyrics.providers import Genius
 
@@ -11,7 +14,6 @@ import spotdl.util
 
 import os
 import urllib.request
-import threading
 
 
 def search_metadata(track, lyrics=True, search_format="{artist} - {track-name}"):
@@ -46,7 +48,7 @@ def download_track(track, arguments):
 
 def download_track_from_metadata(metadata, arguments):
     track = Track(metadata, cache_albumart=(not arguments.no_metadata))
-    # log.info(log_fmt)
+    print(metadata["name"])
 
     stream = metadata["streams"].get(
         quality=arguments.quality,
@@ -114,45 +116,41 @@ def download_tracks_from_file(path, arguments):
 
     # Remove duplicates and empty elements
     # Also strip whitespaces from elements (if any)
-    spotdl.util.remove_duplicates(tracks, condition=lambda x: x, operation=str.strip)
+    spotdl.util.remove_duplicates(
+        tracks,
+        condition=lambda x: x,
+        operation=str.strip
+    )
 
     # Overwrite file
     with open(path, "w") as fout:
         fout.writelines(tracks)
 
-    next_track_metadata = threading.Thread(target=lambda: None)
-    next_track_metadata.start()
     tracks_count = len(tracks)
     current_iteration = 1
 
-    def mutable_assignment(mutable_resource, track):
+    next_track = tracks.pop(0)
-        mutable_resource["next_track"] = search_metadata(
-            track,
-            search_format=arguments.search_format
-        )
-
     metadata = {
         "current_track": None,
-        "next_track": None,
+        "next_track": spotdl.util.ThreadWithReturnValue(
+            target=search_metadata,
+            args=(next_track, True, arguments.search_format)
+        )
     }
+    metadata["next_track"].start()
     while tracks_count > 0:
-        current_track = tracks.pop(0)
         tracks_count -= 1
-        metadata["current_track"] = metadata["next_track"]
+        metadata["current_track"] = metadata["next_track"].join()
         metadata["next_track"] = None
         try:
-            if metadata["current_track"] is None:
-                metadata["current_track"] = search_metadata(
-                    current_track,
-                    search_format=arguments.search_format
-                )
             if tracks_count > 0:
-                next_track = tracks[0]
+                current_track = next_track
-                next_track_metadata = threading.Thread(
+                next_track = tracks.pop(0)
-                    target=mutable_assignment,
+                metadata["next_track"] = spotdl.util.ThreadWithReturnValue(
-                    args=(metadata, next_track)
+                    target=search_metadata,
+                    args=(next_track, True, arguments.search_format)
                 )
-                next_track_metadata.start()
+                metadata["next_track"].start()
 
             log_fmt=(str(current_iteration) + ". {artist} - {track-name}")
             # log.info(log_fmt)
@@ -161,7 +159,6 @@ def download_tracks_from_file(path, arguments):
                 arguments
             )
             current_iteration += 1
-            next_track_metadata.join()
         except (urllib.request.URLError, TypeError, IOError) as e:
             # log.exception(e.args[0])
             # log.warning("Failed. Will retry after other songs\n")

spotdl/config.py

@@ -6,7 +6,6 @@ import spotdl.util
 
 DEFAULT_CONFIGURATION = {
     "spotify-downloader": {
-        "no-remove-original": False,
         "manual": False,
         "no-metadata": False,
         "no-fallback-metadata": False,

spotdl/track.py

@@ -2,11 +2,12 @@ import tqdm
 
 import urllib.request
 import subprocess
-import threading
 
 from spotdl.encode.encoders import EncoderFFmpeg
 from spotdl.metadata.embedders import EmbedderDefault
 
+import spotdl.util
+
 CHUNK_SIZE= 16 * 1024
 
 class Track:
@@ -14,25 +15,18 @@ class Track:
         self.metadata = metadata
         self._chunksize = CHUNK_SIZE
 
-        self._cache_resources = {
-            "albumart": {"content": None, "threadinstance": None }
-        }
         if cache_albumart:
             self._albumart_thread = self._cache_albumart()
 
-    def _fetch_response_content_threaded(self, mutable_resource, url):
+        self._cache_albumart = cache_albumart
-        content = urllib.request.urlopen(url).read()
-        mutable_resource["content"] = content
 
     def _cache_albumart(self):
-        # A hack to get a thread's return value
+        albumart_thread = spotdl.util.ThreadWithReturnValue(
-        albumart_thread = threading.Thread(
+            target=lambda url: urllib.request.urlopen(url).read(),
-            target=self._fetch_response_content_threaded,
+            args=(self.metadata["album"]["images"][0]["url"],)
-            args=(self._cache_resources["albumart"],
-                  self.metadata["album"]["images"][0]["url"]),
         )
         albumart_thread.start()
-        self._cache_resources["albumart"]["threadinstance"] = albumart_thread
+        return albumart_thread
 
     def _calculate_total_chunks(self, filesize):
         return (filesize // self._chunksize) + 1
@@ -79,14 +73,15 @@ class Track:
         process.wait()
 
     def apply_metadata(self, input_path, encoding=None, embedder=EmbedderDefault()):
-        albumart = self._cache_resources["albumart"]
+        if self._cache_albumart:
-        if albumart["threadinstance"]:
+            albumart = self._albumart_thread.join()
-            albumart["threadinstance"].join()
+        else:
+            albumart = None
 
         embedder.apply_metadata(
             input_path,
             self.metadata,
-            cached_albumart=albumart["content"],
+            cached_albumart=albumart,
             encoding=encoding,
         )
 

spotdl/util.py

@@ -4,6 +4,8 @@ import sys
 import math
 import urllib.request
 
+import threading
+
 
 try:
     import winreg
@@ -18,6 +20,26 @@ except ImportError:
     sys.exit(5)
 
 
+# This has been referred from
+# https://stackoverflow.com/a/6894023/6554943
+# It's because threaded functions do not return by default
+# Whereas this will return the value when `join` method
+# is called.
+class ThreadWithReturnValue(threading.Thread):
+    def __init__(self, target=lambda: None, args=()):
+        super().__init__(target=target, args=args)
+        self._return = None
+    def run(self):
+        if self._target is not None:
+            self._return = self._target(
+                *self._args,
+                **self._kwargs
+            )
+    def join(self, *args):
+        super().join(*args)
+        return self._return
+
+
 def merge(base, overrider):
     """ Override default dict with config dict. """
     merger = base.copy()