Class: Aspera::Cli::ExtendedValue

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/aspera/cli/extended_value.rb

Overview

Command line extended values

Constant Summary collapse

DEFAULT_DECODERS =

First is default

%i[none json ruby yaml]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#default_decoder ⇒ Object

Returns the value of attribute default_decoder.



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# File 'lib/aspera/cli/extended_value.rb', line 125

def default_decoder
  @default_decoder
end

Class Method Details

.assert_no_value(value, ext_type) ⇒ Object

The value must be empty

Parameters:

  • value (String) —

    The value as parameter

  • ext_type (Symbol) —

    The method of extended value



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# File 'lib/aspera/cli/extended_value.rb', line 69

def assert_no_value(value, ext_type)
  Aspera.assert(value.empty?, type: BadArgument){"no value allowed for extended value type: #{ext_type}"}
end

.decode_csvt(value) ⇒ Object

Decode comma separated table text



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# File 'lib/aspera/cli/extended_value.rb', line 30

def decode_csvt(value)
  col_titles = nil
  hash_array = []
  CSV.parse(value).each do |values|
    next if values.empty?
    if col_titles.nil?
      col_titles = values
    else
      hash_array.push(col_titles.zip(values).to_h)
    end
  end
  Log.log.warn('Titled CSV file without any row') if hash_array.empty?
  return hash_array
end

.instance ⇒ ExtendedValue

Returns the singleton instance of ExtendedValue

Returns:



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# File 'lib/aspera/cli/extended_value.rb', line 22

class ExtendedValue
  include Singleton

  # First is default
  DEFAULT_DECODERS = %i[none json ruby yaml]

  class << self
    # Decode comma separated table text
    def decode_csvt(value)
      col_titles = nil
      hash_array = []
      CSV.parse(value).each do |values|
        next if values.empty?
        if col_titles.nil?
          col_titles = values
        else
          hash_array.push(col_titles.zip(values).to_h)
        end
      end
      Log.log.warn('Titled CSV file without any row') if hash_array.empty?
      return hash_array
    end

    # JSON Parser, with more information on error location
    # extract a context: 10 chars before and after the error on the given line and display a pointer "^"
    # :reek:UncommunicativeMethodName
    def JSON_parse(value) # rubocop:disable Naming/MethodName
      JSON.parse(value)
    rescue JSON::ParserError => e
      m = /at line (\d+) column (\d+)/.match(e.message)
      raise if m.nil?
      line = m[1].to_i - 1
      column = m[2].to_i - 1
      lines = value.lines
      raise if line >= lines.size
      error_line = lines[line].chomp
      context_col_beg = [column - 10, 0].max
      context_col_end = [column + 10, error_line.length].min
      context = error_line[context_col_beg...context_col_end]
      cursor_pos = column - context_col_beg
      pointer = ' ' * cursor_pos + '^'.blink
      raise BadArgument, "#{e.message}\n#{context}\n#{pointer}"
    end

    # The value must be empty
    # @param value [String] The value as parameter
    # @param ext_type [Symbol] The method of extended value
    def assert_no_value(value, ext_type)
      Aspera.assert(value.empty?, type: BadArgument){"no value allowed for extended value type: #{ext_type}"}
    end

    def read_stdin(mode)
      case mode
      when '' then $stdin.read
      when 'bin' then $stdin.binmode.read
      when 'chomp' then $stdin.chomp
      else raise BadArgument, "`stdin` supports only: '', 'bin' or 'chomp'"
      end
    end
  end

  private

  def initialize
    # Base handlers
    # Other handlers can be set using `on`
    # e.g. `preset` is reader in config plugin
    @handlers = {
      val:    lambda{ |i| i},
      base64: lambda{ |i| Base64.decode64(i)},
      csvt:   lambda{ |i| ExtendedValue.decode_csvt(i)},
      env:    lambda{ |i| ENV.fetch(i, nil)},
      file:   lambda{ |i| File.read(File.expand_path(i))},
      uri:    lambda{ |i| UriReader.read(i)},
      json:   lambda{ |i| ExtendedValue.JSON_parse(i)},
      lines:  lambda{ |i| i.split("\n")},
      list:   lambda{ |i| i[1..].split(i[0])},
      none:   lambda{ |i| ExtendedValue.assert_no_value(i, :none); nil}, # rubocop:disable Style/Semicolon
      path:   lambda{ |i| File.expand_path(i)},
      re:     lambda{ |i| Regexp.new(i, Regexp::MULTILINE)},
      ruby:   lambda{ |i| Environment.secure_eval(i, __FILE__, __LINE__)},
      s:      lambda{ |i| i.to_s},
      secret: lambda{ |i| prompt = i.empty? ? 'secret' : i; $stdin.getpass("#{prompt}> ")}, # rubocop:disable Style/Semicolon
      stdin:  lambda{ |i| ExtendedValue.read_stdin(i)},
      yaml:   lambda{ |i| YAML.load(i)},
      zlib:   lambda{ |i| Zlib::Inflate.inflate(i)},
      extend: lambda{ |i| ExtendedValue.instance.evaluate_extend(i)}
    }
    @regex_single = nil
    @regex_extend = nil
    @default_decoder = nil
    update_regex
  end

  # Update the Regex to match an extended value based on @handlers
  def update_regex
    handler_regex = "#{MARKER_START}(#{modifiers.join('|')})#{MARKER_END}"
    @regex_single = Regexp.new("^#{handler_regex}(.*)$", Regexp::MULTILINE)
    @regex_extend = Regexp.new("^(.*)#{handler_regex}([^#{MARKER_IN_END}]*)#{MARKER_IN_END}(.*)$", Regexp::MULTILINE)
  end

  public

  attr_reader :default_decoder

  def default_decoder=(value)
    Log.log.debug{"Setting default decoder to (#{value.class}) #{value}"}
    Aspera.assert_values(value, DEFAULT_DECODERS)
    value = nil if value.eql?(:none)
    @default_decoder = value
  end

  # List of Extended Value methods
  def modifiers; @handlers.keys; end

  # Add a new handler
  def on(name, &block)
    Aspera.assert_type(name, Symbol){'name'}
    Aspera.assert(block)
    Log.log.debug{"Setting handler for #{name}"}
    @handlers[name] = block
    update_regex
  end

  # Parses a `String` value to extended value.
  # If it is a String using supported extended value modifiers, then evaluate them.
  # Other value types are returned as is.
  # @param value   [String] the value to parse
  # @param context [String] Context in which evaluation is done
  # @param allowed [Array<Class>,NilClass] Expected types
  # @return [String, Integer, Array, Hash, Boolean] Evaluated value
  def evaluate(value, context:, allowed: nil)
    return value unless value.is_a?(String)
    Aspera.assert_array_all(allowed, Class) unless allowed.nil?
    # use default decoder if not an extended value and expect complex types
    using_default_decoder = allowed&.all?{ |t| DEFAULT_PARSER_TYPES.include?(t)} && !@regex_single.match?(value) && !@default_decoder.nil?
    value = [MARKER_START, @default_decoder, MARKER_END, value].join if using_default_decoder
    # First determine decoders, in reversed order
    handlers_reversed = []
    while (m = value.match(@regex_single))
      handler = m[1].to_sym
      handlers_reversed.unshift(handler)
      value = m[2]
      break if SPECIAL_HANDLERS.include?(handler)
    end
    Log.log.trace1{"evaluating: #{handlers_reversed}, value: #{value}"}
    handlers_reversed.each do |handler|
      value = @handlers[handler].call(value)
    rescue => e
      raise BadArgument, "Evaluation of #{handler} for #{context}: #{e.message}"
    end
    return value
  end

  # Find inner extended values
  # Only used in above lambda
  def evaluate_extend(value)
    while (m = value.match(@regex_extend))
      sub_value = "@#{m[2]}:#{m[3]}"
      Log.log.debug{"evaluating #{sub_value}"}
      value = "#{m[1]}#{evaluate(sub_value, context: 'composite extended value')}#{m[4]}"
    end
    return value
  end
  # marker "@"
  MARKER_START = '@'
  # marker ":"
  MARKER_END = ':'
  # marker "@"
  MARKER_IN_END = '@'

  # Special handlers stop processing of handlers on right
  # :extend includes processing of other handlers in itself
  # :val keeps the value intact
  SPECIAL_HANDLERS = %i[extend val].freeze

  # Array and Hash types:
  DEFAULT_PARSER_TYPES = [Array, Hash].freeze
  private_constant :MARKER_START, :MARKER_END, :MARKER_IN_END, :SPECIAL_HANDLERS, :DEFAULT_PARSER_TYPES
end

.JSON_parse(value) ⇒ Object

JSON Parser, with more information on error location extract a context: 10 chars before and after the error on the given line and display a pointer “^” :reek:UncommunicativeMethodName



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# File 'lib/aspera/cli/extended_value.rb', line 48

def JSON_parse(value) # rubocop:disable Naming/MethodName
  JSON.parse(value)
rescue JSON::ParserError => e
  m = /at line (\d+) column (\d+)/.match(e.message)
  raise if m.nil?
  line = m[1].to_i - 1
  column = m[2].to_i - 1
  lines = value.lines
  raise if line >= lines.size
  error_line = lines[line].chomp
  context_col_beg = [column - 10, 0].max
  context_col_end = [column + 10, error_line.length].min
  context = error_line[context_col_beg...context_col_end]
  cursor_pos = column - context_col_beg
  pointer = ' ' * cursor_pos + '^'.blink
  raise BadArgument, "#{e.message}\n#{context}\n#{pointer}"
end

.read_stdin(mode) ⇒ Object 



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# File 'lib/aspera/cli/extended_value.rb', line 73

def read_stdin(mode)
  case mode
  when '' then $stdin.read
  when 'bin' then $stdin.binmode.read
  when 'chomp' then $stdin.chomp
  else raise BadArgument, "`stdin` supports only: '', 'bin' or 'chomp'"
  end
end

Instance Method Details

#evaluate(value, context:, allowed: nil) ⇒ String, ...

Parses a ‘String` value to extended value. If it is a String using supported extended value modifiers, then evaluate them. Other value types are returned as is.

Parameters:

  • value (String) —

    the value to parse

  • context (String) —

    Context in which evaluation is done

  • allowed (Array<Class>, NilClass) (defaults to: nil) —

    Expected types

Returns:

  • (String, Integer, Array, Hash, Boolean) —

    Evaluated value



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# File 'lib/aspera/cli/extended_value.rb', line 153

def evaluate(value, context:, allowed: nil)
  return value unless value.is_a?(String)
  Aspera.assert_array_all(allowed, Class) unless allowed.nil?
  # use default decoder if not an extended value and expect complex types
  using_default_decoder = allowed&.all?{ |t| DEFAULT_PARSER_TYPES.include?(t)} && !@regex_single.match?(value) && !@default_decoder.nil?
  value = [MARKER_START, @default_decoder, MARKER_END, value].join if using_default_decoder
  # First determine decoders, in reversed order
  handlers_reversed = []
  while (m = value.match(@regex_single))
    handler = m[1].to_sym
    handlers_reversed.unshift(handler)
    value = m[2]
    break if SPECIAL_HANDLERS.include?(handler)
  end
  Log.log.trace1{"evaluating: #{handlers_reversed}, value: #{value}"}
  handlers_reversed.each do |handler|
    value = @handlers[handler].call(value)
  rescue => e
    raise BadArgument, "Evaluation of #{handler} for #{context}: #{e.message}"
  end
  return value
end

#evaluate_extend(value) ⇒ Object

Find inner extended values Only used in above lambda



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# File 'lib/aspera/cli/extended_value.rb', line 178

def evaluate_extend(value)
  while (m = value.match(@regex_extend))
    sub_value = "@#{m[2]}:#{m[3]}"
    Log.log.debug{"evaluating #{sub_value}"}
    value = "#{m[1]}#{evaluate(sub_value, context: 'composite extended value')}#{m[4]}"
  end
  return value
end

#modifiers ⇒ Object

List of Extended Value methods



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# File 'lib/aspera/cli/extended_value.rb', line 135

def modifiers; @handlers.keys; end

#on(name, &block) ⇒ Object

Add a new handler



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# File 'lib/aspera/cli/extended_value.rb', line 138

def on(name, &block)
  Aspera.assert_type(name, Symbol){'name'}
  Aspera.assert(block)
  Log.log.debug{"Setting handler for #{name}"}
  @handlers[name] = block
  update_regex
end