mirror of
https://github.com/bookwyrm-social/bookwyrm.git
synced 2024-05-16 23:43:04 +00:00
124 lines
4.7 KiB
Python
124 lines
4.7 KiB
Python
""" Use the range message from isbn-international to hyphenate ISBNs """
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import os
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from typing import Optional
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from xml.etree import ElementTree
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from xml.etree.ElementTree import Element
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import requests
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from bookwyrm import settings
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def _get_rules(element: Element) -> list[Element]:
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if (rules_el := element.find("Rules")) is not None:
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return rules_el.findall("Rule")
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return []
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class IsbnHyphenator:
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"""Class to manage the range message xml file and use it to hyphenate ISBNs"""
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__range_message_url = "https://www.isbn-international.org/export_rangemessage.xml"
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__range_file_path = os.path.join(
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settings.BASE_DIR, "bookwyrm", "isbn", "RangeMessage.xml"
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)
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__element_tree = None
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def update_range_message(self) -> None:
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"""Download the range message xml file and save it locally"""
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response = requests.get(self.__range_message_url)
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with open(self.__range_file_path, "w", encoding="utf-8") as file:
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file.write(response.text)
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self.__element_tree = None
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def hyphenate(self, isbn_13: Optional[str]) -> Optional[str]:
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"""hyphenate the given ISBN-13 number using the range message"""
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if isbn_13 is None:
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return None
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if self.__element_tree is None:
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self.__element_tree = ElementTree.parse(self.__range_file_path)
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gs1_prefix = isbn_13[:3]
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reg_group = self.__find_reg_group(isbn_13, gs1_prefix)
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if reg_group is None:
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return isbn_13 # failed to hyphenate
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registrant = self.__find_registrant(isbn_13, gs1_prefix, reg_group)
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if registrant is None:
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return isbn_13 # failed to hyphenate
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publication = isbn_13[len(gs1_prefix) + len(reg_group) + len(registrant) : -1]
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check_digit = isbn_13[-1:]
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return "-".join((gs1_prefix, reg_group, registrant, publication, check_digit))
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def __find_reg_group(self, isbn_13: str, gs1_prefix: str) -> Optional[str]:
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if self.__element_tree is None:
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self.__element_tree = ElementTree.parse(self.__range_file_path)
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ucc_prefixes_el = self.__element_tree.find("EAN.UCCPrefixes")
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if ucc_prefixes_el is None:
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return None
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for ean_ucc_el in ucc_prefixes_el.findall("EAN.UCC"):
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if (
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prefix_el := ean_ucc_el.find("Prefix")
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) is not None and prefix_el.text == gs1_prefix:
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for rule_el in _get_rules(ean_ucc_el):
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length_el = rule_el.find("Length")
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if length_el is None:
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continue
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length = int(text) if (text := length_el.text) else 0
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if length == 0:
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continue
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range_el = rule_el.find("Range")
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if range_el is None or range_el.text is None:
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continue
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reg_grp_range = [int(x[:length]) for x in range_el.text.split("-")]
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reg_group = isbn_13[len(gs1_prefix) : len(gs1_prefix) + length]
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if reg_grp_range[0] <= int(reg_group) <= reg_grp_range[1]:
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return reg_group
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return None
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return None
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def __find_registrant(
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self, isbn_13: str, gs1_prefix: str, reg_group: str
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) -> Optional[str]:
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from_ind = len(gs1_prefix) + len(reg_group)
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if self.__element_tree is None:
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self.__element_tree = ElementTree.parse(self.__range_file_path)
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reg_groups_el = self.__element_tree.find("RegistrationGroups")
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if reg_groups_el is None:
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return None
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for group_el in reg_groups_el.findall("Group"):
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if (
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prefix_el := group_el.find("Prefix")
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) is not None and prefix_el.text == "-".join((gs1_prefix, reg_group)):
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for rule_el in _get_rules(group_el):
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length_el = rule_el.find("Length")
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if length_el is None:
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continue
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length = int(text) if (text := length_el.text) else 0
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if length == 0:
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continue
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range_el = rule_el.find("Range")
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if range_el is None or range_el.text is None:
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continue
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registrant_range = [
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int(x[:length]) for x in range_el.text.split("-")
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]
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registrant = isbn_13[from_ind : from_ind + length]
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if registrant_range[0] <= int(registrant) <= registrant_range[1]:
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return registrant
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return None
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return None
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hyphenator_singleton = IsbnHyphenator()
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