Adrien Widart
320025ee63
To reproduce the issue:
(Need stock_barcode)
1. Create a product:
- Barcode: 1234567890123
2. Print the label
3. Try to scan the barcode and check the value read.
Error: The value is 1234567890128, the last digit is incorrect (8
instead of 3)
When printing a barcode, we use the library 'report-lab' to generate a
barcode image from a value and a barcode type. In case of EAN-13, if the
value contains a non-digit character, it will raise an error. We then
catch the error and retry to generate the barcode according to the
barcode type Code128:
https://github.com/odoo/odoo/blob/87698d90f02bfe93c6e643f4876a5ccd74788eff/odoo/addons/base/models/ir_actions_report.py#L569-L575
However, if the value contains only digits, the method will use the 12
first digits:
https://github.com/mattjmorrison/ReportLab/blob/dade0f303cb6fcdbe535c4cc92e6102c2417b699/src/reportlab/graphics/barcode/eanbc.py#L187-L188
and will then add the last one, the check digit, which is computed by
the library. This explains why, in the above use case, the barcode value
returned by the scanner is not the same than the expected one.
Note: Similar behavior with type EAN-8
OPW-2902150
closes odoo/odoo#97052
X-original-commit: a2c7470f8fd46b2520f7b8f0750c63216273ce96
Related: odoo/enterprise#30160
Signed-off-by: Steve Van Essche <svs@odoo.com>
Signed-off-by: Adrien Widart <awt@odoo.com>
55 lines
2.2 KiB
Python
55 lines
2.2 KiB
Python
# -*- coding: utf-8 -*-
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# Part of Odoo. See LICENSE file for full copyright and licensing details.
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import re
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def get_barcode_check_digit(numeric_barcode):
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""" Computes and returns the barcode check digit. The used algorithm
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follows the GTIN specifications and can be used by all compatible
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barcode nomenclature, like as EAN-8, EAN-12 (UPC-A) or EAN-13.
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https://www.gs1.org/sites/default/files/docs/barcodes/GS1_General_Specifications.pdf
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https://www.gs1.org/services/how-calculate-check-digit-manually
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:param numeric_barcode: the barcode to verify/recompute the check digit
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:type numeric_barcode: str
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:return: the number corresponding to the right check digit
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:rtype: int
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"""
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# Multiply value of each position by
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# N1 N2 N3 N4 N5 N6 N7 N8 N9 N10 N11 N12 N13 N14 N15 N16 N17 N18
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# x3 X1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 CHECKSUM
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oddsum = evensum = 0
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code = numeric_barcode[-2::-1] # Remove the check digit and reverse the barcode.
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# The CHECKSUM digit is removed because it will be recomputed and it must not interfer with
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# the computation. Also, the barcode is inverted, so the barcode length doesn't matter.
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# Otherwise, the digits' group (even or odd) could be different according to the barcode length.
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for i, digit in enumerate(code):
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if i % 2 == 0:
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evensum += int(digit)
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else:
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oddsum += int(digit)
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total = evensum * 3 + oddsum
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return (10 - total % 10) % 10
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def check_barcode_encoding(barcode, encoding):
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""" Checks if the given barcode is correctly encoded.
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:return: True if the barcode string is encoded with the provided encoding.
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:rtype: bool
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"""
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encoding = encoding.lower()
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if encoding == "any":
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return True
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barcode_sizes = {
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'ean8': 8,
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'ean13': 13,
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'gtin14': 14,
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'upca': 12,
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'sscc': 18,
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}
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barcode_size = barcode_sizes[encoding]
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return (encoding != 'ean13' or barcode[0] != '0') \
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and len(barcode) == barcode_size \
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and re.match(r"^\d+$", barcode) \
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and get_barcode_check_digit(barcode) == int(barcode[-1])
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