Module: Gmail::ImapExtensions

Defined in:
lib/gmail/imap_extensions.rb

Constant Summary collapse

LABELS_FLAG_REGEXP =
/\\([^\x80-\xff(){ \x00-\x1f\x7f%"\\]+)/n

Class Method Summary collapse

Class Method Details

.add_unescape(klass = String) ⇒ Object

PNIRP


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# File 'lib/gmail/imap_extensions.rb', line 120

def self.add_unescape(klass = String)
  klass.class_eval do
    # Add a method to string which unescapes special characters
    # We use a simple state machine to ensure that specials are not
    # themselves escaped
    def unescape
      unesc = ''
      special = false
      escapes = { '\\' => '\\',
                  '"'  => '"',
                  'n' => "\n",
                  't' => "\t",
                  'r' => "\r",
                  'f' => "\f",
                  'v' => "\v",
                  '0' => "\0",
                  'a' => "\a"
                }

      self.each_char do |char|
        if special
          # If in special mode, add in the replaced special char if there's a match
          # Otherwise, add in the backslash and the current character
          unesc << (escapes.keys.include?(char) ? escapes[char] : "\\#{char}")
          special = false
        else
          # Toggle special mode if backslash is detected; otherwise just add character
          if char == '\\'
            special = true
          else
            unesc << char
          end
        end
      end
      unesc
    end
  end
end

.patch_net_imap_response_parser(klass = Net::IMAP::ResponseParser) ⇒ Object


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# File 'lib/gmail/imap_extensions.rb', line 5

def self.patch_net_imap_response_parser(klass = Net::IMAP::ResponseParser)
  # https://github.com/ruby/ruby/blob/4d426fc2e03078d583d5d573d4863415c3e3eb8d/lib/net/imap.rb#L2258
  klass.class_eval do
    def msg_att(n = -1)
      match(Net::IMAP::ResponseParser::T_LPAR)
      attr = {}
      while true
        token = lookahead
        case token.symbol
        when Net::IMAP::ResponseParser::T_RPAR
          shift_token
          break
        when Net::IMAP::ResponseParser::T_SPACE
          shift_token
          next
        end
        case token.value
        when /\A(?:ENVELOPE)\z/ni
          name, val = envelope_data
        when /\A(?:FLAGS)\z/ni
          name, val = flags_data
        when /\A(?:INTERNALDATE)\z/ni
          name, val = internaldate_data
        when /\A(?:RFC822(?:\.HEADER|\.TEXT)?)\z/ni
          name, val = rfc822_text
        when /\A(?:RFC822\.SIZE)\z/ni
          name, val = rfc822_size
        when /\A(?:BODY(?:STRUCTURE)?)\z/ni
          name, val = body_data
        when /\A(?:UID)\z/ni
          name, val = uid_data

        # Gmail extension
        # Cargo-cult code warning: no idea why the regexp works - just copying a pattern
        when /\A(?:X-GM-LABELS)\z/ni
          name, val = x_gm_labels_data
        when /\A(?:X-GM-MSGID)\z/ni
          name, val = uid_data
        when /\A(?:X-GM-THRID)\z/ni
          name, val = uid_data
        # End Gmail extension

        else
          parse_error("unknown attribute `%s' for {%d}", token.value, n)
        end
        attr[name] = val
      end
      return attr
    end

    # Based on Net::IMAP#flags_data, but calling x_gm_labels_list to parse labels
    def x_gm_labels_data
      token = match(self.class::T_ATOM)
      name = token.value.upcase
      match(self.class::T_SPACE)
      return name, x_gm_label_list
    end

    # Based on Net::IMAP#flag_list with a modified Regexp
    # Labels are returned as escape-quoted strings
    # We extract the labels using a regexp which extracts any unescaped strings
    def x_gm_label_list
      if @str.index(/\(([^)]*)\)/ni, @pos)
        resp = extract_labels_response

        # We need to manually update the position of the regexp to prevent trip-ups
        @pos += resp.length - 1

        # `resp` will look something like this:
        # ("\\Inbox" "\\Sent" "one's and two's" "some new label" Awesome Ni&APE-os)
        result = resp.gsub(/^\s*\(|\)+\s*$/, '').scan(/"([^"]*)"|([^\s"]+)/ni).flatten.compact.collect(&:unescape)
        result.map do |x|
          flag = x.scan(LABELS_FLAG_REGEXP)
          if flag.empty?
            x
          else
            flag.first.first.capitalize.untaint.intern
          end
        end
      else
        parse_error("invalid label list")
      end
    end

    # The way Gmail return tokens can cause issues with Net::IMAP's reader,
    # so we need to extract this section manually
    def extract_labels_response
      special, quoted = false, false
      index, paren_count = 0, 0

      # Start parsing response string for the labels section, parentheses inclusive
      labels_header = "X-GM-LABELS ("
      start = @str.index(labels_header) + labels_header.length - 1
      substr = @str[start..-1]
      substr.each_char do |char|
        index += 1
        case char
        when '('
          paren_count += 1 unless quoted
        when ')'
          paren_count -= 1 unless quoted
          break if paren_count == 0
        when '"'
          quoted = !quoted unless special
        end
        special = (char == '\\' && !special)
      end
      substr[0..index]
    end
  end # class_eval

  # Add String#unescape
  add_unescape
end