Class: Postkode

Inherits:
Object
  • Object
show all
Defined in:
lib/postkode.rb

Overview

Handles validation of UK-style postcodes

Constant Summary collapse

A1 =

Validating UK Postcodes Correct as at 2014-09-15 References below www.gov.uk/government/uploads/system/uploads/attachment_data/file/283357/ILRSpecification2013_14Appendix_C_Dec2012_v1.pdf en.wikipedia.org/wiki/Postcodes_in_the_United_Kingdom#Validation Areas with only single-digit districts: BR, FY, HA, HD, HG, HR, HS, HX, JE,

LD, SM, SR, WC, WN, ZE (although WC is always subdivided by a
further letter, e.g. WC1A).

Areas with only double-digit districts: AB, LL, SO. Areas with a district ‘0’ (zero): BL, BS, CM, CR, FY, HA, PR, SL, SS (BS is

the only area to have both a district 0 and a district 10).

The following central London single-digit districts have been further

divided by inserting a letter after the digit and before the space:
EC1-EC4 (but not EC50), SW1, W1, WC1, WC2, and part of E1 (E1W),
N1 (N1C and N1P), NW1 (NW1W) and SE1 (SE1P).

The letters QVX are not used in the first position. The letters IJZ are not used in the second position. The only letters to appear in the third position are ABCDEFGHJKPSTUW when

the structure starts with A9A.

The only letters to appear in the fourth position are ABEHMNPRVWXY when

the structure starts with AA9A.

The final two letters do not use the letters CIKMOV, so as not to resemble

digits or each other when hand-written.

Post code sectors are one of ten digits: 0 to 9 with 0 only used once 9

has been used in a post town, save for Croydon and Newport (above).

'[A-PR-UWYZ]'
A2 = 
'[A-HK-Y]'
A3 = 
'[A-HJKPS-UW]'
A4 = 
'[ABEHMNPRV-XY]'
A5 = 
'[ABD-HJLN-UW-Z]'
N = 
'[0-9]'
AANN =

the six possible first-part combos

A1 + A2 + N + N
AANA = 
A1 + A2 + N + A4
ANA = 
A1 + N + A3
ANN = 
A1 + N + N
AAN = 
A1 + A2 + N
AN = 
A1 + N
PART_ONE = 
[AANN, AANA, ANA, ANN, AAN, AN].join('|')
PART_TWO = 
N + A5 + A5
NORMAL_POSTCODE_VALID = 
"^(#{PART_ONE})[ ]*(#{PART_TWO})$"
NORMAL_POSTCODE_PATTERN = 
/(#{PART_ONE})[ ]*(#{PART_TWO})/
NORMAL_PART_POSTCODE_PATTERN = 
/[ ]*(#{PART_ONE})[ ]*/
NORMAL_POSTCODE_RE = 
Regexp.new(NORMAL_POSTCODE_VALID, Regexp::IGNORECASE)

Class Method Summary collapse

Class Method Details

.find_in_string(string) ⇒ Object 



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# File 'lib/postkode.rb', line 73

def self.find_in_string(string)
  res = string.upcase.scan(NORMAL_POSTCODE_PATTERN)
  res.length > 0 ? res : nil
end

.find_partial_in_string(string) ⇒ Object 



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# File 'lib/postkode.rb', line 78

def self.find_partial_in_string(string)
  res = string.upcase.scan(NORMAL_PART_POSTCODE_PATTERN)
  res.length > 0 ? res : nil
end

.get_first_section(string) ⇒ Object 



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# File 'lib/postkode.rb', line 59

def self.get_first_section(string)
  get_outcode(string)
end

.get_inward(string) ⇒ Object 



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# File 'lib/postkode.rb', line 68

def self.get_inward(string)
  found = Postkode.validate(string, true)
  found ? found[1] : nil
end

.get_outcode(string) ⇒ Object 



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# File 'lib/postkode.rb', line 63

def self.get_outcode(string)
  found = Postkode.validate(string, true)
  found ? found[0] : nil
end

.random ⇒ Object 



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# File 'lib/postkode.rb', line 91

def self.random()
  generator_pattern = "#{[AANN, AANA, ANA, ANN, AAN, AN].sample} #{PART_TWO}"
  StringRandom.random_regex(generator_pattern)
end

.validate(string, return_parts = false) ⇒ Object 



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# File 'lib/postkode.rb', line 51

def self.validate(string, return_parts = false)
  return false if string.nil? || string == '' || string == false
  result = string.match(NORMAL_POSTCODE_RE)
  return false if result.nil?

  return_parts ? result[1..2] : true
end

.validate_and_normalize(string) ⇒ Object 



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# File 'lib/postkode.rb', line 83

def self.validate_and_normalize(string)
  return nil unless validate(string)
  validate(string, true).
    map(&:to_s).
    map(&:upcase).
    join(" ")
end