Merge remote-tracking branch 'derrotebaron/master'

diff --combined youtube_dl/utils.py
index b433b591bdfc690064523e226227fdbe34373c37,daf94abd1d541d77e8b74f0f17e6fde780b054e8..3536a5bd6f3216a62eaaec2ba11a08893c5e62ab
--- 1/youtube_dl/utils.py
--- 2/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@@ -399,9 -399,8 +399,9 @@@ def formatSeconds(secs)
  def make_HTTPS_handler(params, **kwargs):
      opts_no_check_certificate = params.get('nocheckcertificate', False)
      if hasattr(ssl, 'create_default_context'):  # Python >= 3.4 or 2.7.9
 -        context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
 +        context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
          if opts_no_check_certificate:
 +            context.check_hostname = False
              context.verify_mode = ssl.CERT_NONE
          try:
              return YoutubeDLHTTPSHandler(params, context=context, **kwargs)
@@@ -612,7 -611,9 +612,9 @@@ class YoutubeDLHandler(compat_urllib_re
  
      def http_request(self, req):
          for h, v in std_headers.items():
-             if h not in req.headers:
+             # Capitalize is needed because of Python bug 2275: http://bugs.python.org/issue2275
+             # The dict keys are capitalized because of this bug by urllib
+             if h.capitalize() not in req.headers:
                  req.add_header(h, v)
          if 'Youtubedl-no-compression' in req.headers:
              if 'Accept-encoding' in req.headers:
@@@ -722,7 -723,6 +724,7 @@@ def unified_strdate(date_str, day_first
          '%b %dst %Y %I:%M%p',
          '%b %dnd %Y %I:%M%p',
          '%b %dth %Y %I:%M%p',
 +        '%Y %m %d',
          '%Y-%m-%d',
          '%Y/%m/%d',
          '%Y/%m/%d %H:%M:%S',
@@@ -1277,7 -1277,7 +1279,7 @@@ def parse_duration(s)
      s = s.strip()
  
      m = re.match(
 -        r'''(?ix)T?
 +        r'''(?ix)(?:P?T)?
          (?:
              (?P<only_mins>[0-9.]+)\s*(?:mins?|minutes?)\s*|
              (?P<only_hours>[0-9.]+)\s*(?:hours?)|
@@@ -1612,14 -1612,6 +1614,14 @@@ def urlhandle_detect_ext(url_handle)
      except AttributeError:  # Python < 3
          getheader = url_handle.info().getheader
  
 +    cd = getheader('Content-Disposition')
 +    if cd:
 +        m = re.match(r'attachment;\s*filename="(?P<filename>[^"]+)"', cd)
 +        if m:
 +            e = determine_ext(m.group('filename'), default_ext=None)
 +            if e:
 +                return e
 +
      return getheader('Content-Type').split("/")[1]
  
  
@@@ -1631,23 -1623,3 +1633,23 @@@ def age_restricted(content_limit, age_l
      if content_limit is None:
          return False  # Content available for everyone
      return age_limit < content_limit
 +
 +
 +def is_html(first_bytes):
 +    """ Detect whether a file contains HTML by examining its first bytes. """
 +
 +    BOMS = [
 +        (b'\xef\xbb\xbf', 'utf-8'),
 +        (b'\x00\x00\xfe\xff', 'utf-32-be'),
 +        (b'\xff\xfe\x00\x00', 'utf-32-le'),
 +        (b'\xff\xfe', 'utf-16-le'),
 +        (b'\xfe\xff', 'utf-16-be'),
 +    ]
 +    for bom, enc in BOMS:
 +        if first_bytes.startswith(bom):
 +            s = first_bytes[len(bom):].decode(enc, 'replace')
 +            break
 +    else:
 +        s = first_bytes.decode('utf-8', 'replace')
 +
 +    return re.match(r'^\s*<', s)