Make sure netrc works for all extractors with login support

Fixes #5112

youtube_dl/extractor/atresplayer.py

@@ -19,6 +19,7 @@ from ..utils import (
 
 class AtresPlayerIE(InfoExtractor):
     _VALID_URL = r'https?://(?:www\.)?atresplayer\.com/television/[^/]+/[^/]+/[^/]+/(?P<id>.+?)_\d+\.html'
+    _NETRC_MACHINE = 'atresplayer'
     _TESTS = [
         {
             'url': 'http://www.atresplayer.com/television/programas/el-club-de-la-comedia/temporada-4/capitulo-10-especial-solidario-nochebuena_2014122100174.html',

youtube_dl/extractor/crunchyroll.py

@@ -29,6 +29,7 @@ from ..aes import (
 
 class CrunchyrollIE(InfoExtractor):
     _VALID_URL = r'https?://(?:(?P<prefix>www|m)\.)?(?P<url>crunchyroll\.(?:com|fr)/(?:[^/]*/[^/?&]*?|media/\?id=)(?P<video_id>[0-9]+))(?:[/?&]|$)'
+    _NETRC_MACHINE = 'crunchyroll'
     _TESTS = [{
         'url': 'http://www.crunchyroll.com/wanna-be-the-strongest-in-the-world/episode-1-an-idol-wrestler-is-born-645513',
         'info_dict': {

youtube_dl/extractor/gdcvault.py

@@ -12,6 +12,7 @@ from ..utils import remove_end
 
 class GDCVaultIE(InfoExtractor):
     _VALID_URL = r'https?://(?:www\.)?gdcvault\.com/play/(?P<id>\d+)/(?P<name>(\w|-)+)'
+    _NETRC_MACHINE = 'gdcvault'
     _TESTS = [
         {
             'url': 'http://www.gdcvault.com/play/1019721/Doki-Doki-Universe-Sweet-Simple',

youtube_dl/extractor/lynda.py

@@ -19,6 +19,7 @@ class LyndaBaseIE(InfoExtractor):
     _LOGIN_URL = 'https://www.lynda.com/login/login.aspx'
     _SUCCESSFUL_LOGIN_REGEX = r'isLoggedIn: true'
     _ACCOUNT_CREDENTIALS_HINT = 'Use --username and --password options to provide lynda.com account credentials.'
+    _NETRC_MACHINE = 'lynda'
 
     def _real_initialize(self):
         self._login()

youtube_dl/extractor/twitch.py

@@ -23,6 +23,7 @@ class TwitchBaseIE(InfoExtractor):
     _API_BASE = 'https://api.twitch.tv'
     _USHER_BASE = 'http://usher.twitch.tv'
     _LOGIN_URL = 'https://secure.twitch.tv/user/login'
+    _NETRC_MACHINE = 'twitch'
 
     def _handle_error(self, response):
         if not isinstance(response, dict):