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Machine Readable Zone code generator

This module generates Machine Readable Zone codes, as used in passports and visas. For rendering in print, use the OCR-B font. This module only generates text. Quick hack, not fault tolerant, not well tested, etc. BSD licensed.

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#!/usr/bin/env python
"""
Module to generate Machine Readable Zone codes for use in passports and visas.
Only handles code generation, not rendering. For documentation on format, see
http://www.highprogrammer.com/alan/numbers/mrp.html
"""

class MRZ:
    """
    Class builds MRZ data lines.
    
    >>> print MRZ(doctype='P', countrycode='Utopia', lastname='Eriksson',
    ...   givennames='Anna Maria', passportno='L898902C', nationality='Utopian', 
    ...   dob='690806', sex='f', expirydate='940623', personalno='ZE184226B')()
    P<UTOERIKSSON<<ANNA<MARIA<<<<<<<<<<<<<<<<<<<
    L898902C<3UTO6908061F9406236ZE184226B<<<<<14
    >>> l = MRZ(doctype='P', countrycode='ind', lastname='Mangalswamy',
    ...   givennames='Sampath Saraswat Sampigeanna',
    ...   passportno='M447002', nationality='ind',
    ...   dob='791203', sex='m', expirydate='120225')(False)
    >>> print l[0]
    P<INDMANGALSWAMY<<SAMPATH<SARASWAT<SAMPIGEAN
    >>> print l[1]
    M447002<<3IND7912034M1202258<<<<<<<<<<<<<<<4
    >>> print MRZ(doctype='P', countrycode='ind', lastname='Mangalswamy',
    ...   givennames='Sampath Saraswat Sampigeanna', suffix='Jr',
    ...   passportno='M447002', nationality='ind',
    ...   dob='791203', sex='m', expirydate='120225')()
    P<INDMANGALSWAMY<JR<<SAMPATH<SARASWAT<SAMPIG
    M447002<<3IND7912034M1202258<<<<<<<<<<<<<<<4
    """

basefields = [
        ['doctype', 2, None],
        ['countrycode', 3, None],
        # ['name', 39, None],
        ['passportno', 9, None],
        ['nationality', 3, None],
        ['dob', 6, '1234567890'],
        ['sex', 1, 'MF'],
        ['expirydate', 6, '1234567890'],
        ['personalno', 14, None],
        ]

line1 = ['doctype', 'countrycode', 'name']
    line2 = ['passportno', 'passportnocheck', 'nationality', 'dob', 'dobcheck',
             'sex', 'expirydate', 'expirycheck', 'personalno',
             'personalnocheck', 'finalcheck']

checkweights = [7, 3, 1]
    checktable = {'<': 0}
    for n in range(10): # 0-9
        checktable[str(n)] = n
    for n in zip(range(ord('A'), ord('Z')+1), range(10, 36)): # A-Z = 10-35
        checktable[chr(n[0])] = n[1]

def _cleanfield(self, data, length, validchars=None):
        if data is None:
            data = ''
        else:
            data = data.upper().strip()
        if validchars is None:
            validchars = list('ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890')
        else:
            validchars = list(validchars)
        cleaned = []
        for char in data:
            if char in validchars:
                cleaned.append(char)
            else:
                cleaned.append(' ')
        if len(cleaned) > length:
            cleaned = cleaned[:length]
        elif len(cleaned) < length:
            cleaned.append(' '*(length-len(cleaned))) # Str not char, but ok.
        return ''.join(cleaned).replace(' ', '<')

def _calcChecksum(self, data):
        if not data.replace('<', ''):
            return '<'
        nums = []
        for i in range(len(data)):
            nums.append(self.checktable[data[i]] *
                self.checkweights[i % len(self.checkweights)])
        return str(sum(nums) % 10)

def __init__(self, **kw):
        formatted = {}
        # Get basefields
        for field in self.basefields:
            formatted[field[0]] = self._cleanfield(kw.get(field[0], ''),
                                                   field[1], field[2])
        # Get name
        formatted['name'] = self._cleanfield(kw.get('lastname', '') +
            ('suffix' in kw and (' ' + kw['suffix']) or '') + '  ' +
            kw.get('givennames', ''), 39) # Field length is 39.
        # Calculate check fields
        formatted['passportnocheck'] = self._calcChecksum(
            formatted['passportno'])
        formatted['dobcheck'] = self._calcChecksum(formatted['dob'])
        formatted['expirycheck'] = self._calcChecksum(formatted['expirydate'])
        formatted['personalnocheck'] = self._calcChecksum(
            formatted['personalno'])
        formatted['finalcheck'] = self._calcChecksum(
            formatted['passportno'] + formatted['passportnocheck'] +
            formatted['dob'] + formatted['dobcheck'] +
            formatted['expirydate'] + formatted['expirycheck'] +
            formatted['personalno'] + formatted['personalnocheck'])

self.fline1 = ''.join([formatted[field] for field in self.line1])
        self.fline2 = ''.join([formatted[field] for field in self.line2])
        self.rendered = "%s\n%s" % (self.fline1, self.fline2)

def __call__(self, rendered=True):
        if rendered:
            return self.rendered
        else:
            return [self.fline1, self.fline2]

if __name__=='__main__':
    import doctest
    print "Running tests..."
    doctest.testmod()

Last modified 2006-05-29 13:33

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Machine Readable Zone code generator

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