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https://github.com/python-escpos/python-escpos
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Feature/check barcodes (#255)
* add a method to check barcode code format ensure that the code to print is compatible with the ESC/POS formats and also automatically check this format before printing (barcode() method). * rewrite test using pytest's parametrize functionality * add test for the 'check' argument * update authors list
This commit is contained in:
Lucy Linder
committed by
Patrick Kanzler
Patrick Kanzler
parent
d78a6f1699
commit
456f5b7aa6
@@ -225,6 +225,24 @@ BARCODE_TYPE_B = {
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'GS1 DATABAR EXPANDED': _SET_BARCODE_TYPE(78),
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}
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BARCODE_FORMATS = {
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'UPC-A': ([(11, 12)], "^[0-9]{11,12}$"),
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'UPC-E': ([(7, 8), (11, 12)], "^([0-9]{7,8}|[0-9]{11,12})$"),
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'EAN13': ([(12, 13)], "^[0-9]{12,13}$"),
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'EAN8': ([(7, 8)], "^[0-9]{7,8}$"),
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'CODE39': ([(1, 255)], "^([0-9A-Z \$\%\+\-\.\/]+|\*[0-9A-Z \$\%\+\-\.\/]+\*)$"),
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'ITF': ([(2, 255)], "^([0-9]{2})+$"),
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'NW7': ([(1, 255)], "^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"),
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'CODABAR': ([(1, 255)], "^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"), # Same as NW7
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'CODE93': ([(1, 255)], "^[\\x00-\\x7F]+$"),
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'CODE128': ([(2, 255)], "^\{[A-C][\\x00-\\x7F]+$"),
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'GS1-128': ([(2, 255)], "^\{[A-C][\\x00-\\x7F]+$"), # same as CODE128
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'GS1 DATABAR OMNIDIRECTIONAL': ([(13,13)], "^[0-9]{13}$"),
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'GS1 DATABAR TRUNCATED': ([(13,13)], "^[0-9]{13}$"), # same as GS1 omnidirectional
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'GS1 DATABAR LIMITED': ([(13,13)], "^[01][0-9]{12}$"),
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'GS1 DATABAR EXPANDED': ([(2,255)], "^\([0-9][A-Za-z0-9 \!\"\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\_\{]+$"),
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}
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BARCODE_TYPES = {
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'A': BARCODE_TYPE_A,
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'B': BARCODE_TYPE_B,
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@@ -19,13 +19,14 @@ import qrcode
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import textwrap
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import six
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import time
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from re import match as re_match
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import barcode
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from barcode.writer import ImageWriter
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from .constants import ESC, GS, NUL, QR_ECLEVEL_L, QR_ECLEVEL_M, QR_ECLEVEL_H, QR_ECLEVEL_Q
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from .constants import QR_MODEL_1, QR_MODEL_2, QR_MICRO, BARCODE_TYPES, BARCODE_HEIGHT, BARCODE_WIDTH
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from .constants import BARCODE_FONT_A, BARCODE_FONT_B
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from .constants import BARCODE_FONT_A, BARCODE_FONT_B, BARCODE_FORMATS
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from .constants import BARCODE_TXT_OFF, BARCODE_TXT_BTH, BARCODE_TXT_ABV, BARCODE_TXT_BLW
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from .constants import TXT_SIZE, TXT_NORMAL
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from .constants import SET_FONT
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@@ -287,17 +288,42 @@ class Escpos(object):
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else:
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self.magic.force_encoding(code)
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@staticmethod
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def check_barcode(bc, code):
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"""
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This method checks if the barcode is in the proper format.
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The validation concerns the barcode length and the set of characters, but won't compute/validate any checksum.
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The full set of requirement for each barcode type is available in the ESC/POS documentation.
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As an example, using EAN13, the barcode `12345678901` will be correct, because it can be rendered by the
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printer. But it does not suit the EAN13 standard, because the checksum digit is missing. Adding a wrong
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checksum in the end will also be considered correct, but adding a letter won't (EAN13 is numeric only).
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.. todo:: Add a method to compute the checksum for the different standards
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.. todo:: For fixed-length standards with mandatory checksum (EAN, UPC),
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compute and add the checksum automatically if missing.
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:param bc: barcode format, see :py:func`~escpos.Escpos.barcode`
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:param code: alphanumeric data to be printed as bar code, see :py:func`~escpos.Escpos.barcode`
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:return: bool
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"""
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if bc not in BARCODE_FORMATS:
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return False
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bounds, regex = BARCODE_FORMATS[bc]
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return any(bound[0] <= len(code) <= bound[1] for bound in bounds) and re_match(regex, code)
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def barcode(self, code, bc, height=64, width=3, pos="BELOW", font="A",
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align_ct=True, function_type=None):
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align_ct=True, function_type=None, check=True):
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""" Print Barcode
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This method allows to print barcodes. The rendering of the barcode is done by the printer and therefore has to
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be supported by the unit. Currently you have to check manually whether your barcode text is correct. Uncorrect
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barcodes may lead to unexpected printer behaviour. There are two forms of the barcode function. Type A is
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default but has fewer barcodes, while type B has some more to choose from.
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.. todo:: Add a method to check barcode codes. Alternatively or as an addition write explanations about each
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barcode-type. Research whether the check digits can be computed autmatically.
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be supported by the unit. By default, this method will check whether your barcode text is correct, that is
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the characters and lengths are supported by ESCPOS. Call the method with `check=False` to disable the check, but
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note that uncorrect barcodes may lead to unexpected printer behaviour.
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There are two forms of the barcode function. Type A is default but has fewer barcodes,
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while type B has some more to choose from.
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Use the parameters `height` and `width` for adjusting of the barcode size. Please take notice that the barcode
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will not be printed if it is outside of the printable area. (Which should be impossible with this method, so
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@@ -365,6 +391,10 @@ class Escpos(object):
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function based on the current profile.
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*default*: A
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:param check: If this parameter is True, the barcode format will be checked to ensure it meets the bc
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requirements as defigned in the esc/pos documentation. See py:func:`~escpos.Escpos.check_barcode`
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for more information. *default*: True.
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:raises: :py:exc:`~escpos.exceptions.BarcodeSizeError`,
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:py:exc:`~escpos.exceptions.BarcodeTypeError`,
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:py:exc:`~escpos.exceptions.BarcodeCodeError`
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@@ -387,12 +417,19 @@ class Escpos(object):
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bc_types = BARCODE_TYPES[function_type.upper()]
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if bc.upper() not in bc_types.keys():
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raise BarcodeTypeError((
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"Barcode type '{bc}' not valid for barcode function type "
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"Barcode '{bc}' not valid for barcode function type "
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"{function_type}").format(
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bc=bc,
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function_type=function_type,
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))
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if check and not self.check_barcode(bc, code):
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raise BarcodeCodeError((
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"Barcode '{code}' not in a valid format for type '{bc}'").format(
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code=code,
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bc=bc,
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))
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# Align Bar Code()
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if align_ct:
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self._raw(TXT_STYLE['align']['center'])
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@@ -77,9 +77,10 @@ class BarcodeSizeError(Error):
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class BarcodeCodeError(Error):
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""" No Barcode code was supplied.
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""" No Barcode code was supplied, or it is incorrect.
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No data for the barcode has been supplied in :py:meth:`escpos.escpos.Escpos.barcode`.
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No data for the barcode has been supplied in :py:meth:`escpos.escpos.Escpos.barcode` or the the `check` parameter
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was True and the check failed.
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The returncode for this exception is `30`.
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"""
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def __init__(self, msg=""):
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