Module: AWSCronParser::Helpers::CronExpression

Includes:
Calendar
Defined in:
lib/aws_cron_parser/helpers/cron_expression.rb

Constant Summary collapse

AWS_CRON_REGEX =

Expression type patterns

/^cron\((?<expression>.+)\)$/i
RATE_REGEX = 
/^rate\((?<value>\d+)\s+(?<unit>minute|minutes|hour|hours|day|days)\)$/i
MACRO_REGEX = 
/^@(?<macro>yearly|monthly|weekly|daily|hourly)$/i
AT_REGEX = 
/^at\((?<datetime>.+)\)$/i
CRON_PATTERNS =

Consolidated CRON field patterns

{
  digit_only: /^\d+$/,
  step: %r{^\*/(\d+)$|^0/(\d+)$},
  range: /^(\d+)-(\d+)$/,
  step_range: %r{(\d+)/(\d+)},
  nth_weekday_numeric: /^\d+#\d+$/,
  last_weekday_numeric: /^\d+L$/,
  nth_weekday: /^(?<weekday>\d)#(?<occurrence>\d)$/,
  nth_weekday_name: /^(?<name>[A-Z]{3}|[A-Z]+)#(?<occurrence>\d+)$/i,
  last_weekday: /^(?<weekday>\d)L$/,
  last_weekday_name: /^(?<name>[A-Z]{3}|[A-Z]+)L$/i
}.freeze
DIGIT_ONLY_REGEX =

Backward compatibility - individual constants for existing code

CRON_PATTERNS[:digit_only]
RANGE_REGEX = 
CRON_PATTERNS[:range]
STEP_RANGE_REGEX = 
CRON_PATTERNS[:step_range]
NTH_WEEKDAY_REGEX = 
CRON_PATTERNS[:nth_weekday]
LAST_WEEKDAY_REGEX = 
CRON_PATTERNS[:last_weekday]

Constants included from Calendar

AWSCronParser::Helpers::Calendar::AWS_DAY_NAMES, AWSCronParser::Helpers::Calendar::AWS_WEEKDAY_NAMES, AWSCronParser::Helpers::Calendar::DAY_NAMES, AWSCronParser::Helpers::Calendar::MONTH_ABBREVIATIONS, AWSCronParser::Helpers::Calendar::MONTH_FULL_NAMES, AWSCronParser::Helpers::Calendar::MONTH_NAMES, AWSCronParser::Helpers::Calendar::WEEKDAY_NAMES

Instance Method Summary collapse

Methods included from Calendar

#day_name, #month_abbr_to_num, #month_name, #weekday_abbr_to_num, #weekday_name_from_abbr

Instance Method Details

#day_only?(source) ⇒ Boolean

Check if day-of-month field is specified and day-of-week is '?'

Returns:

  • (Boolean) 


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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 99

def day_only?(source)
  tokens = source.split(/\s+/)
  return false if tokens.length < 5

  dom_idx = tokens.length == 5 ? 2 : 3
  dow_idx = tokens.length == 5 ? 4 : 5

  dom = tokens[dom_idx]
  dow = tokens[dow_idx]

  dom != '?' && dow == '?'
end

#detect_complex_step(source) ⇒ Object

Detect if the CRON expression uses complex step patterns (with ranges or lists)



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 74

def detect_complex_step(source)
  tokens = source.split(/\s+/)
  return false if tokens.length < 5

  tokens.each do |field|
    return true if field.include?('/') && field.exclude?('#') && field.exclude?('L')
  end
  false
end

#detect_dom_pattern(source, pattern_char) ⇒ Object

Detect if a specific pattern character exists in the day-of-month field



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 65

def detect_dom_pattern(source, pattern_char)
  tokens = source.split(/\s+/)
  return false if tokens.length < 5

  dom_field = tokens.length == 5 ? tokens[2] : tokens[3]
  dom_field.include?(pattern_char)
end

#detect_pattern(source, pattern_char) ⇒ Object

Detect if a specific pattern character exists in the day-of-week field



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 56

def detect_pattern(source, pattern_char)
  tokens = source.split(/\s+/)
  return false if tokens.length < 5

  dow_field = tokens.length == 5 ? tokens[4] : tokens[5]
  dow_field.include?(pattern_char)
end

#expand_dow_step(part) ⇒ Object

Expands */2, MON/2 or 2-6/2 over the AWS weekday range (1=SUN..7=SAT). Without this the field yields no days at all and the caller searches a whole year before giving up.



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 164

def expand_dow_step(part)
  base, step = part.split('/')
  step = step.to_i
  return [] if step <= 0

  if base.include?('-')
    start_num, end_num = base.split('-').map { |v| AWS_DAY_NAMES[v.upcase] || v.to_i }
  elsif ['*', '?'].include?(base)
    start_num = 1
    end_num = 7
  else
    start_num = AWS_DAY_NAMES[base.upcase] || base.to_i
    end_num = 7
  end

  (start_num..end_num).step(step).to_a
end

#month_only?(source) ⇒ Boolean

Check if month field matches actual month

Returns:

  • (Boolean) 


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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 85

def month_only?(source)
  tokens = source.split(/\s+/)
  return false if tokens.length < 5

  dom_idx = tokens.length == 5 ? 2 : 3
  dow_idx = tokens.length == 5 ? 4 : 5

  dom = tokens[dom_idx]
  dow = tokens[dow_idx]

  ['*', '?'].include?(dom) && dow != '*' && dow != '?' && dow.exclude?('#') && dow.exclude?('L')
end

#normalize_month_field(month) ⇒ Object

Normalize month field (e.g., "jan", "feb-mar", "apr/2")



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 235

def normalize_month_field(month)
  return month if ['*', '?'].include?(month) || month =~ /^\d/

  # Handle ranges like "jan-mar"
  if month.include?('-')
    parts = month.split('-')
    start_num = month_abbr_to_num(parts[0])
    end_num = month_abbr_to_num(parts[1])
    return "#{start_num}-#{end_num}"
  end

  # Handle lists like "jan,mar,jun"
  if month.include?(',')
    parts = month.split(',').map { |m| month_abbr_to_num(m) }
    return parts.join(',')
  end

  # Handle steps like "jan/2" and "*/2" - the wildcard base is not a name
  if month.include?('/')
    parts = month.split('/')
    start = ['*', '?'].include?(parts[0]) ? parts[0] : month_abbr_to_num(parts[0])
    return "#{start}/#{parts[1]}"
  end

  # Single month abbreviation
  month_abbr_to_num(month).to_s
end

#normalize_source(source) ⇒ Object

Normalize expression by stripping cron() wrapper if present



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 36

def normalize_source(source)
  return source if source.blank?

  normalized = source.strip
  if (match = normalized.match(AWS_CRON_REGEX))
    content = match[:expression].strip
    parts = content.split(/\s+/)
    normalized = if parts.length == 7
                   parts[0..5].join(' ')
                 elsif parts.length == 6
                   parts[0..4].join(' ')
                 else
                   parts.join(' ')
                 end
  end

  normalized
end

#normalize_weekday_field(weekday, is_aws: false) ⇒ Object

Normalize weekday field (e.g., "mon", "tue-wed", "fri/2")



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 195

def normalize_weekday_field(weekday, is_aws: false)
  return weekday if ['*', '?'].include?(weekday) || weekday =~ /^\d/

  # Handle ranges like "mon-wed"
  if weekday.include?('-')
    parts = weekday.split('-')
    start_num = weekday_abbr_to_num(parts[0], is_aws: is_aws)
    end_num = weekday_abbr_to_num(parts[1], is_aws: is_aws)
    return "#{start_num}-#{end_num}"
  end

  # Handle lists like "mon,wed,fri"
  if weekday.include?(',')
    parts = weekday.split(',').map { |w| weekday_abbr_to_num(w, is_aws: is_aws) }
    return parts.join(',')
  end

  # Handle steps like "mon/2" and "*/2" - the wildcard base is not a name
  if weekday.include?('/')
    parts = weekday.split('/')
    start = ['*', '?'].include?(parts[0]) ? parts[0] : weekday_abbr_to_num(parts[0], is_aws: is_aws)
    return "#{start}/#{parts[1]}"
  end

  # Single weekday abbreviation
  weekday_abbr_to_num(weekday, is_aws: is_aws).to_s
end

#normalize_weekday_in_last_spec(dow_spec) ⇒ Object

Normalize weekday in last spec (e.g., "MONL" to "1L")



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 224

def normalize_weekday_in_last_spec(dow_spec)
  return dow_spec if dow_spec.match?(CRON_PATTERNS[:last_weekday_numeric])

  match = dow_spec.match(CRON_PATTERNS[:last_weekday_name])
  return dow_spec unless match

  day_num = AWS_DAY_NAMES[match[:name].upcase] || match[:name]
  "#{day_num}L"
end

#normalize_weekday_in_nth_spec(dow_spec, is_aws: false) ⇒ Object

Normalize weekday in nth spec (e.g., "MON#2" to "1#2")



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 183

def normalize_weekday_in_nth_spec(dow_spec, is_aws: false)
  return dow_spec if dow_spec.match?(CRON_PATTERNS[:nth_weekday_numeric])

  match = dow_spec.match(CRON_PATTERNS[:nth_weekday_name])
  return dow_spec unless match

  day_names = is_aws ? AWS_DAY_NAMES : DAY_NAMES
  day_num = day_names[match[:name].upcase] || match[:name]
  "#{day_num}##{match[:occurrence]}"
end

#parse_dow_field(field) ⇒ Object

Parse the day-of-week field (0 = Sunday, 1 = Monday, ..., 6 = Saturday)



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 139

def parse_dow_field(field)
  return (0..6).to_a if ['*', '?'].include?(field)

  result = []
  field.split(',').each do |part|
    part = part.strip
    if part.include?('/')
      result.concat(expand_dow_step(part))
    elsif part.include?('-')
      start_num, end_num = part.split('-')
      start_num = AWS_DAY_NAMES[start_num.upcase] || start_num.to_i
      end_num = AWS_DAY_NAMES[end_num.upcase] || end_num.to_i
      (start_num..end_num).each { |n| result << n }
    elsif part.match?(/^\d+$/)
      result << part.to_i
    elsif AWS_DAY_NAMES[part.upcase]
      result << AWS_DAY_NAMES[part.upcase]
    end
  end
  result.sort.uniq
end

#parse_simple_field(field, range) ⇒ Object

Parse a simple cron field (minute, hour, day, month, or weekday)



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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 113

def parse_simple_field(field, range)
  return range.to_a if ['*', '?'].include?(field)
  return [field.to_i] if field.match?(/^\d+$/)

  if field.include?('-')
    start_num, end_num = field.split('-').map(&:to_i)
    (start_num..end_num).to_a
  elsif field.include?(',')
    field.split(',').map(&:to_i)
  elsif field.include?('/')
    start_str, step_str = field.split('/')
    start = start_str == '*' ? range.first : start_str.to_i
    step = step_str.to_i
    result = []
    current = start
    while current <= range.last
      result << current
      current += step
    end
    result
  else
    [field.to_i]
  end
end

#weekday_only?(source) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/aws_cron_parser/helpers/cron_expression.rb', line 263

def weekday_only?(source)
  tokens = normalize_source(source).split(/\s+/)
  return false if tokens.length < 5

  dom_idx = tokens.length == 5 ? 2 : 3
  dow_idx = tokens.length == 5 ? 4 : 5

  dom = tokens[dom_idx]
  dow = tokens[dow_idx]

  dom == '?' && dow != '?' && dow.exclude?('#') && dow.exclude?('L')
end