Module: Tztr

Defined in:
lib/tztr.rb,
lib/tztr/version.rb

Constant Summary collapse

PATTERNS = 
[
  # ISO 8601 with Z or offset: 2026-04-03T12:34:56Z, 2026-04-03T12:34:56.123+00:00
  /\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+-]\d{2}:?\d{2})/,
  # ISO 8601 without timezone: 2026-04-03T12:34:56
  /\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?/,
  # Date space time with tz: 2026-04-03 12:34:56 UTC
  /\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}(?:\.\d+)? ?(?:UTC|GMT|[A-Z]{2,4}|[+-]\d{4})/,
  # Date space time: 2026-04-03 12:34:56
  /\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}(?:\.\d+)?/,
  # Time with tz: 12:34:56 UTC, 12:34 PST
  /\b\d{1,2}:\d{2}(?::\d{2}(?:\.\d+)?)? ?(?:UTC|GMT|[A-Z]{2,4}|[+-]\d{4})\b/,
  # Time with offset: 12:34:56+00:00
  /\b\d{1,2}:\d{2}(?::\d{2}(?:\.\d+)?)?[+-]\d{2}:?\d{2}\b/,
  # Bare time: 12:34:56, 12:34
  /\b\d{1,2}:\d{2}(?::\d{2}(?:\.\d+)?)?\b/,
].freeze
TIMEZONE_ALIASES = 
{
  # UTC
  'utc' => 'UTC', 'gmt' => 'UTC', 'z' => 'UTC',
  # US Eastern
  'est' => 'America/New_York', 'edt' => 'America/New_York', 'et' => 'America/New_York',
  'eastern' => 'America/New_York',
  # US Central
  'cst' => 'America/Chicago', 'cdt' => 'America/Chicago', 'ct' => 'America/Chicago',
  'central' => 'America/Chicago',
  # US Mountain
  'mst' => 'America/Denver', 'mdt' => 'America/Denver', 'mt' => 'America/Denver',
  'mountain' => 'America/Denver',
  # US Pacific
  'pst' => 'America/Los_Angeles', 'pdt' => 'America/Los_Angeles', 'pt' => 'America/Los_Angeles',
  'pacific' => 'America/Los_Angeles',
  # US Other
  'hst' => 'Pacific/Honolulu', 'akst' => 'America/Anchorage', 'akdt' => 'America/Anchorage',
  # Europe
  'cet' => 'Europe/Berlin', 'cest' => 'Europe/Berlin',
  'gmt' => 'Europe/London', 'bst' => 'Europe/London',
  'ist' => 'Asia/Kolkata',
  # Asia/Pacific
  'jst' => 'Asia/Tokyo', 'kst' => 'Asia/Seoul',
  'cst_china' => 'Asia/Shanghai', 'hkt' => 'Asia/Hong_Kong',
  'aest' => 'Australia/Sydney', 'aedt' => 'Australia/Sydney',
  'nzst' => 'Pacific/Auckland', 'nzdt' => 'Pacific/Auckland',
  # Cities
  'sf' => 'America/Los_Angeles', 'la' => 'America/Los_Angeles', 'seattle' => 'America/Los_Angeles',
  'denver' => 'America/Denver',
  'chicago' => 'America/Chicago',
  'nyc' => 'America/New_York', 'boston' => 'America/New_York', 'miami' => 'America/New_York',
  'london' => 'Europe/London',
  'paris' => 'Europe/Paris', 'berlin' => 'Europe/Berlin', 'amsterdam' => 'Europe/Amsterdam',
  'tokyo' => 'Asia/Tokyo',
  'sydney' => 'Australia/Sydney',
  'mumbai' => 'Asia/Kolkata', 'delhi' => 'Asia/Kolkata',
  'shanghai' => 'Asia/Shanghai', 'beijing' => 'Asia/Shanghai',
  'hong_kong' => 'Asia/Hong_Kong', 'hongkong' => 'Asia/Hong_Kong',
  'singapore' => 'Asia/Singapore',
  'seoul' => 'Asia/Seoul',
  'honolulu' => 'Pacific/Honolulu', 'hawaii' => 'Pacific/Honolulu',
  'anchorage' => 'America/Anchorage', 'alaska' => 'America/Anchorage',
  'toronto' => 'America/Toronto',
  'vancouver' => 'America/Vancouver',
  'auckland' => 'Pacific/Auckland',
  'dubai' => 'Asia/Dubai',
  'sao_paulo' => 'America/Sao_Paulo',
}.freeze
VERSION = 
"0.1.0"

Class Method Summary collapse

Class Method Details

.format_time(time, fmt, original) ⇒ Object 



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# File 'lib/tztr.rb', line 131

def format_time(time, fmt, original)
  case fmt
  when :short then return time.strftime('%Y-%m-%d %H:%M')
  when :time then return time.strftime('%H:%M:%S')
  when :iso then return time.strftime('%Y-%m-%d %H:%M:%S')
  end

  # Preserve input format
  tz = time.utc_offset == 0 ? 'Z' : time.strftime('%:z')

  case original
  when /^\d{4}-\d{2}-\d{2}T/
    has_frac = original.match?(/T\d{2}:\d{2}:\d{2}\.\d+/)
    base = has_frac ? time.strftime('%Y-%m-%dT%H:%M:%S.%L') : time.strftime('%Y-%m-%dT%H:%M:%S')
    base + tz
  when /^\d{4}-\d{2}-\d{2} /
    has_frac = original.match?(/ \d{2}:\d{2}:\d{2}\.\d+/)
    base = has_frac ? time.strftime('%Y-%m-%d %H:%M:%S.%L') : time.strftime('%Y-%m-%d %H:%M:%S')
    base + " " + (time.utc? ? 'UTC' : time.strftime('%Z'))
  when /^\d{1,2}:\d{2}(?::\d{2})/
    time.strftime('%H:%M:%S') + " " + (time.utc? ? 'UTC' : time.strftime('%Z'))
  when /^\d{1,2}:\d{2}/
    time.strftime('%H:%M') + " " + (time.utc? ? 'UTC' : time.strftime('%Z'))
  else
    time.strftime('%Y-%m-%d %H:%M:%S') + " " + (time.utc? ? 'UTC' : time.strftime('%Z'))
  end
end

.has_timezone?(str) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tztr.rb', line 127

def has_timezone?(str)
  str.match?(/Z$|[+-]\d{2}:?\d{2}$| ?(?:UTC|GMT|[A-Z]{2,4}|[+-]\d{4})$/)
end

.parse(str, from: nil, to: 'UTC') ⇒ Object 



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# File 'lib/tztr.rb', line 113

def parse(str, from: nil, to: 'UTC')
  if has_timezone?(str)
    Time.parse(str)
  elsif from
    ENV['TZ'] = from
    t = Time.parse(str).utc
    ENV['TZ'] = to
    t.localtime
  else
    ENV['TZ'] = to
    Time.parse(str)
  end
end

.resolve_tz(input) ⇒ Object 



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# File 'lib/tztr.rb', line 75

def resolve_tz(input)
  return input if input.nil?

  # Numeric offset: -7 -> Etc/GMT+7 (POSIX sign is inverted)
  if input.match?(/\A[+-]?\d{1,2}\z/)
    n = input.to_i
    return 'UTC' if n == 0

    return "Etc/GMT#{n > 0 ? '-' : '+'}#{n.abs}"
  end

  TIMEZONE_ALIASES[input.downcase.tr(' ', '_')] || input
end

.translate(line, to: 'UTC', from: nil, format: nil) ⇒ Object 



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# File 'lib/tztr.rb', line 89

def translate(line, to: 'UTC', from: nil, format: nil)
  to = resolve_tz(to)
  from = resolve_tz(from)
  ENV['TZ'] = to
  result = line.dup

  PATTERNS.each do |pattern|
    next unless result.match?(pattern)

    result.gsub!(pattern) do |match|
      begin
        time = parse(match, from:, to:)
        format_time(time.localtime, format, match)
      rescue ArgumentError
        match
      end
    end

    break result
  end

  result
end