old_contents: from __future__ import unicode_literals
  
  import re
  
  from .common import PostProcessor
  from ..utils import PostProcessingError
  
  
  class MetadataFromTitlePPError(PostProcessingError):
      pass
  
  
  class MetadataFromTitlePP(PostProcessor):
      def __init__(self, downloader, titleformat):
          super(MetadataFromTitlePP, self).__init__(downloader)
          self._titleformat = titleformat
          self._titleregex = self.format_to_regex(titleformat)
  
      def format_to_regex(self, fmt):
          """
          Converts a string like
             '%(title)s - %(artist)s'
          to a regex like
             '(?P<title>.+)\ \-\ (?P<artist>.+)'
          """
          lastpos = 0
          regex = ''
          # replace %(..)s with regex group and escape other string parts
          for match in re.finditer(r'%\((\w+)\)s', fmt):
              regex += re.escape(fmt[lastpos:match.start()])
              regex += r'(?P<' + match.group(1) + '>.+)'
              lastpos = match.end()
          if lastpos < len(fmt):
              regex += re.escape(fmt[lastpos:len(fmt)])
          return regex
  
      def run(self, info):
          title = info['title']
          match = re.match(self._titleregex, title)
          if match is None:
              raise MetadataFromTitlePPError('Could not interpret title of video as "%s"' % self._titleformat)
          for attribute, value in match.groupdict().items():
              value = match.group(attribute)
              info[attribute] = value
              self._downloader.to_screen('[fromtitle] parsed ' + attribute + ': ' + value)
  
          return [], info
  
new_contents: from __future__ import unicode_literals
  
  import re
  
  from .common import PostProcessor
  from ..utils import PostProcessingError
  
  
  class MetadataFromTitlePPError(PostProcessingError):
      pass
  
  
  class MetadataFromTitlePP(PostProcessor):
      def __init__(self, downloader, titleformat):
          super(MetadataFromTitlePP, self).__init__(downloader)
          self._titleformat = titleformat
          self._titleregex = self.format_to_regex(titleformat)
  
      def format_to_regex(self, fmt):
          """
          Converts a string like
             '%(title)s - %(artist)s'
          to a regex like
             '(?P<title>.+)\ \-\ (?P<artist>.+)'
          """
          lastpos = 0
          regex = ''
          # replace %(..)s with regex group and escape other string parts
          for match in re.finditer(r'%\((\w+)\)s', fmt):
              regex += re.escape(fmt[lastpos:match.start()])
              regex += r'(?P<' + match.group(1) + '>.+)'
              lastpos = match.end()
          if lastpos < len(fmt):
              regex += re.escape(fmt[lastpos:len(fmt)])
          return regex
  
      def run(self, info):
          title = info['title']
          match = re.match(self._titleregex, title)
          if match is None:
              self._downloader.to_screen('[fromtitle] Could not interpret title of video as "%s"' % self._titleformat)
              return [], info
          for attribute, value in match.groupdict().items():
              value = match.group(attribute)
              info[attribute] = value
              self._downloader.to_screen('[fromtitle] parsed ' + attribute + ': ' + value)
  
          return [], info
  
subject: Make --metadata-from-title non fatal