treasure-data/embulk-parser-query_string

require "addressable/uri"

module Embulk
  module Parser

    class QueryString < ParserPlugin
      Plugin.register_parser("query_string", self)

      def self.transaction(config, &control)
        decoder_task = config.load_config(Java::LineDecoder::DecoderTask)

        task = {
          "decoder" => DataSource.from_java(decoder_task.dump),
          "strip_quote" => config.param("strip_quote", :bool, default: true),
          "strip_whitespace" => config.param("strip_whitespace", :bool, default: true),
          "capture" => config.param("capture", :string, default: nil),
        }

        columns = []
        schema = config.param("columns", :array, default: [])
        schema.each do |column|
          name = column["name"]
          type = column["type"].to_sym

          columns << Column.new(nil, name, type)
        end

        yield(task, columns)
      end

      def init
        @options = {
          strip_quote: task["strip_quote"],
          strip_whitespace: task["strip_whitespace"],
          capture: task["capture"],
        }

        @decoder = task.param("decoder", :hash).load_task(Java::LineDecoder::DecoderTask)
      end

      def run(file_input)
        decoder = Java::LineDecoder.new(file_input.to_java, @decoder)

        while decoder.nextFile
          while line = decoder.poll
            process_line(line)
          end
        end

        page_builder.finish
      end

      def self.valid_query_string?(qs)
        if qs.match(/[\s]/)
          Embulk.logger.warn "'#{qs}' contains unescaped space"
          return false
        end

        if qs.match(/[^\x20-\x7e]/)
          Embulk.logger.warn "'#{qs}' contains non-ascii character (maybe unescaped)"
          return false
        end

        true
      end

      def self.parse(line, options = {})
        if options[:capture]
          line = line.match(options[:capture]).to_a[1] || ""
          # TODO: detect incorrect regexp given
        end

        return if line == ""

        line.strip! if options[:strip_whitespace]
        if options[:strip_quote]
          line = line[/\A(?:["'])?(.*?)(?:["'])?\z/, 1]
        end

        begin
          uri = Addressable::URI.parse("?#{line}")
          if valid_query_string?(uri.query)
            uri.query_values(Hash)
          else
            nil
          end
        rescue ArgumentError
          Embulk.logger.warn "Failed parse: #{line}"
          nil
        end
      end

      private

      def process_line(line)
        record = self.class.parse(line, @options)

        return unless record

        # NOTE: this conversion is needless afrer Embulk 0.6.13
        values = schema.map do |column|
          name = column.name
          value = record[name]

          next nil if value.nil? || value.empty?

          begin
            case column.type
            when :long
              value.strip.empty? ? nil : Integer(value)
            when :timestamp
              value.strip.empty? ? nil : Time.parse(value)
            when :boolean
              truthy_value?(value)
            else
              value.to_s
            end
          rescue => e
            raise ConfigError.new("Cast failed '#{value}' as '#{column.type}' (key is '#{column.name}')")
          end
        end

        page_builder.add(values)
      end

      def truthy_value?(str)
        # Same as Embulk csv parser
        # https://github.com/embulk/embulk/blob/v0.8.9/embulk-standards/src/main/java/org/embulk/standards/CsvParserPlugin.java#L35-L41
        %w(
          true True TRUE
          yes Yes YES
          t T y Y
          on On ON
          1
        ).include?(str)
      end
    end
  end
end