Fix W504 and disable W503 (closes #20863)
[youtube-dl] / youtube_dl / downloader / fragment.py
index 44a3c10403bedb2380178320d42729f94d63eee5..f2e5733b6406603f9a52b26b65bd4bc3cc833fec 100644 (file)
@@ -2,7 +2,7 @@ from __future__ import division, unicode_literals
 
 import os
 import time
-import io
+import json
 
 from .common import FileDownloader
 from .http import HttpFD
@@ -11,7 +11,6 @@ from ..utils import (
     encodeFilename,
     sanitize_open,
     sanitized_Request,
-    compat_str,
 )
 
 
@@ -30,6 +29,28 @@ class FragmentFD(FileDownloader):
                         and hlsnative only)
     skip_unavailable_fragments:
                         Skip unavailable fragments (DASH and hlsnative only)
+    keep_fragments:     Keep downloaded fragments on disk after downloading is
+                        finished
+
+    For each incomplete fragment download youtube-dl keeps on disk a special
+    bookkeeping file with download state and metadata (in future such files will
+    be used for any incomplete download handled by youtube-dl). This file is
+    used to properly handle resuming, check download file consistency and detect
+    potential errors. The file has a .ytdl extension and represents a standard
+    JSON file of the following format:
+
+    extractor:
+        Dictionary of extractor related data. TBD.
+
+    downloader:
+        Dictionary of downloader related data. May contain following data:
+            current_fragment:
+                Dictionary with current (being downloaded) fragment data:
+                index:  0-based index of current fragment among all fragments
+            fragment_count:
+                Total count of fragments
+
+    This feature is experimental and file format may change in future.
     """
 
     def report_retry_fragment(self, err, frag_index, count, retries):
@@ -48,31 +69,69 @@ class FragmentFD(FileDownloader):
         self._prepare_frag_download(ctx)
         self._start_frag_download(ctx)
 
+    @staticmethod
+    def __do_ytdl_file(ctx):
+        return not ctx['live'] and not ctx['tmpfilename'] == '-'
+
+    def _read_ytdl_file(self, ctx):
+        assert 'ytdl_corrupt' not in ctx
+        stream, _ = sanitize_open(self.ytdl_filename(ctx['filename']), 'r')
+        try:
+            ctx['fragment_index'] = json.loads(stream.read())['downloader']['current_fragment']['index']
+        except Exception:
+            ctx['ytdl_corrupt'] = True
+        finally:
+            stream.close()
+
+    def _write_ytdl_file(self, ctx):
+        frag_index_stream, _ = sanitize_open(self.ytdl_filename(ctx['filename']), 'w')
+        downloader = {
+            'current_fragment': {
+                'index': ctx['fragment_index'],
+            },
+        }
+        if ctx.get('fragment_count') is not None:
+            downloader['fragment_count'] = ctx['fragment_count']
+        frag_index_stream.write(json.dumps({'downloader': downloader}))
+        frag_index_stream.close()
+
     def _download_fragment(self, ctx, frag_url, info_dict, headers=None):
-        down = io.BytesIO()
-        success = ctx['dl'].download(down, {
+        fragment_filename = '%s-Frag%d' % (ctx['tmpfilename'], ctx['fragment_index'])
+        success = ctx['dl'].download(fragment_filename, {
             'url': frag_url,
             'http_headers': headers or info_dict.get('http_headers'),
         })
         if not success:
             return False, None
-        frag_content = down.getvalue()
+        down, frag_sanitized = sanitize_open(fragment_filename, 'rb')
+        ctx['fragment_filename_sanitized'] = frag_sanitized
+        frag_content = down.read()
         down.close()
         return True, frag_content
 
     def _append_fragment(self, ctx, frag_content):
-        ctx['dest_stream'].write(frag_content)
-        if not (ctx.get('live') or ctx['tmpfilename'] == '-'):
-            frag_index_stream, _ = sanitize_open(ctx['tmpfilename'] + '.fragindex', 'w')
-            frag_index_stream.write(compat_str(ctx['frag_index']))
-            frag_index_stream.close()
+        try:
+            ctx['dest_stream'].write(frag_content)
+            ctx['dest_stream'].flush()
+        finally:
+            if self.__do_ytdl_file(ctx):
+                self._write_ytdl_file(ctx)
+            if not self.params.get('keep_fragments', False):
+                os.remove(encodeFilename(ctx['fragment_filename_sanitized']))
+            del ctx['fragment_filename_sanitized']
 
     def _prepare_frag_download(self, ctx):
         if 'live' not in ctx:
             ctx['live'] = False
+        if not ctx['live']:
+            total_frags_str = '%d' % ctx['total_frags']
+            ad_frags = ctx.get('ad_frags', 0)
+            if ad_frags:
+                total_frags_str += ' (not including %d ad)' % ad_frags
+        else:
+            total_frags_str = 'unknown (live)'
         self.to_screen(
-            '[%s] Total fragments: %s'
-            % (self.FD_NAME, ctx['total_frags'] if not ctx['live'] else 'unknown (live)'))
+            '[%s] Total fragments: %s' % (self.FD_NAME, total_frags_str))
         self.report_destination(ctx['filename'])
         dl = HttpQuietDownloader(
             self.ydl,
@@ -89,22 +148,43 @@ class FragmentFD(FileDownloader):
         tmpfilename = self.temp_name(ctx['filename'])
         open_mode = 'wb'
         resume_len = 0
-        frag_index = 0
+
         # Establish possible resume length
         if os.path.isfile(encodeFilename(tmpfilename)):
             open_mode = 'ab'
             resume_len = os.path.getsize(encodeFilename(tmpfilename))
-            if os.path.isfile(encodeFilename(tmpfilename + '.fragindex')):
-                frag_index_stream, _ = sanitize_open(tmpfilename + '.fragindex', 'r')
-                frag_index = int(frag_index_stream.read())
-                frag_index_stream.close()
+
+        # Should be initialized before ytdl file check
+        ctx.update({
+            'tmpfilename': tmpfilename,
+            'fragment_index': 0,
+        })
+
+        if self.__do_ytdl_file(ctx):
+            if os.path.isfile(encodeFilename(self.ytdl_filename(ctx['filename']))):
+                self._read_ytdl_file(ctx)
+                is_corrupt = ctx.get('ytdl_corrupt') is True
+                is_inconsistent = ctx['fragment_index'] > 0 and resume_len == 0
+                if is_corrupt or is_inconsistent:
+                    message = (
+                        '.ytdl file is corrupt' if is_corrupt else
+                        'Inconsistent state of incomplete fragment download')
+                    self.report_warning(
+                        '%s. Restarting from the beginning...' % message)
+                    ctx['fragment_index'] = resume_len = 0
+                    if 'ytdl_corrupt' in ctx:
+                        del ctx['ytdl_corrupt']
+                    self._write_ytdl_file(ctx)
+            else:
+                self._write_ytdl_file(ctx)
+                assert ctx['fragment_index'] == 0
+
         dest_stream, tmpfilename = sanitize_open(tmpfilename, open_mode)
 
         ctx.update({
             'dl': dl,
             'dest_stream': dest_stream,
             'tmpfilename': tmpfilename,
-            'frag_index': frag_index,
             # Total complete fragments downloaded so far in bytes
             'complete_frags_downloaded_bytes': resume_len,
         })
@@ -116,8 +196,8 @@ class FragmentFD(FileDownloader):
         state = {
             'status': 'downloading',
             'downloaded_bytes': ctx['complete_frags_downloaded_bytes'],
-            'frag_index': ctx['frag_index'],
-            'frag_count': total_frags,
+            'fragment_index': ctx['fragment_index'],
+            'fragment_count': total_frags,
             'filename': ctx['filename'],
             'tmpfilename': ctx['tmpfilename'],
         }
@@ -139,13 +219,13 @@ class FragmentFD(FileDownloader):
             frag_total_bytes = s.get('total_bytes') or 0
             if not ctx['live']:
                 estimated_size = (
-                    (ctx['complete_frags_downloaded_bytes'] + frag_total_bytes) /
-                    (state['frag_index'] + 1) * total_frags)
+                    (ctx['complete_frags_downloaded_bytes'] + frag_total_bytes)
+                    / (state['fragment_index'] + 1) * total_frags)
                 state['total_bytes_estimate'] = estimated_size
 
             if s['status'] == 'finished':
-                state['frag_index'] += 1
-                ctx['frag_index'] = state['frag_index']
+                state['fragment_index'] += 1
+                ctx['fragment_index'] = state['fragment_index']
                 state['downloaded_bytes'] += frag_total_bytes - ctx['prev_frag_downloaded_bytes']
                 ctx['complete_frags_downloaded_bytes'] = state['downloaded_bytes']
                 ctx['prev_frag_downloaded_bytes'] = 0
@@ -167,15 +247,21 @@ class FragmentFD(FileDownloader):
 
     def _finish_frag_download(self, ctx):
         ctx['dest_stream'].close()
-        if os.path.isfile(encodeFilename(ctx['tmpfilename'] + '.fragindex')):
-            os.remove(encodeFilename(ctx['tmpfilename'] + '.fragindex'))
+        if self.__do_ytdl_file(ctx):
+            ytdl_filename = encodeFilename(self.ytdl_filename(ctx['filename']))
+            if os.path.isfile(ytdl_filename):
+                os.remove(ytdl_filename)
         elapsed = time.time() - ctx['started']
-        self.try_rename(ctx['tmpfilename'], ctx['filename'])
-        fsize = os.path.getsize(encodeFilename(ctx['filename']))
+
+        if ctx['tmpfilename'] == '-':
+            downloaded_bytes = ctx['complete_frags_downloaded_bytes']
+        else:
+            self.try_rename(ctx['tmpfilename'], ctx['filename'])
+            downloaded_bytes = os.path.getsize(encodeFilename(ctx['filename']))
 
         self._hook_progress({
-            'downloaded_bytes': fsize,
-            'total_bytes': fsize,
+            'downloaded_bytes': downloaded_bytes,
+            'total_bytes': downloaded_bytes,
             'filename': ctx['filename'],
             'status': 'finished',
             'elapsed': elapsed,