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#!/usr/bin/python3
"""
Reads through the wiki dump, attempts to parse short-descriptions,
and adds them to a database
"""
# In testing, this script took over 10 hours to run, and generated about 5GB
import argparse
import sys, os, re
import bz2, html, mwxml, mwparserfromhell
import sqlite3
DUMP_FILE = 'enwiki-20220501-pages-articles-multistream.xml.bz2' # Had about 22e6 pages
DB_FILE = 'desc_data.db'
# Regexps
DESC_LINE_REGEX = re.compile('^ *[A-Z\'"]')
EMBEDDED_HTML_REGEX = re.compile(r'<[^<]+/>|<!--[^<]+-->|<[^</]+>([^<]*|[^<]*<[^<]+>[^<]*)</[^<]+>|<[^<]+$')
# Recognises a self-closing HTML tag, a tag with 0 children, tag with 1 child with 0 children, or unclosed tag
CONVERT_TEMPLATE_REGEX = re.compile(r'{{convert\|(\d[^|]*)\|(?:(to|-)\|(\d[^|]*)\|)?([a-z][^|}]*)[^}]*}}')
def convertTemplateReplace(match):
""" Used in regex-substitution with CONVERT_TEMPLATE_REGEX """
if match.group(2) is None:
return f'{match.group(1)} {match.group(4)}'
else:
return f'{match.group(1)} {match.group(2)} {match.group(3)} {match.group(4)}'
PARENS_GROUP_REGEX = re.compile(r' \([^()]*\)')
LEFTOVER_BRACE_REGEX = re.compile(r'(?:{\||{{).*')
def genData(dumpFile: str, dbFile: str) -> None:
print('Creating database')
if os.path.exists(dbFile):
raise Exception(f'ERROR: Existing {dbFile}')
dbCon = sqlite3.connect(dbFile)
dbCur = dbCon.cursor()
dbCur.execute('CREATE TABLE pages (id INT PRIMARY KEY, title TEXT UNIQUE)')
dbCur.execute('CREATE INDEX pages_title_idx ON pages(title COLLATE NOCASE)')
dbCur.execute('CREATE TABLE redirects (id INT PRIMARY KEY, target TEXT)')
dbCur.execute('CREATE INDEX redirects_idx ON redirects(target)')
dbCur.execute('CREATE TABLE descs (id INT PRIMARY KEY, desc TEXT)')
#
print('Iterating through dump file')
with bz2.open(dumpFile, mode='rt') as file:
for pageNum, page in enumerate(mwxml.Dump.from_file(file), 1):
if pageNum % 1e4 == 0:
print(f'At page {pageNum}')
# Parse page
if page.namespace == 0:
try:
dbCur.execute('INSERT INTO pages VALUES (?, ?)', (page.id, convertTitle(page.title)))
except sqlite3.IntegrityError as e:
# Accounts for certain pages that have the same title
print(f'Failed to add page with title "{page.title}": {e}', file=sys.stderr)
continue
if page.redirect is not None:
dbCur.execute('INSERT INTO redirects VALUES (?, ?)', (page.id, convertTitle(page.redirect)))
else:
revision = next(page)
desc = parseDesc(revision.text)
if desc is not None:
dbCur.execute('INSERT INTO descs VALUES (?, ?)', (page.id, desc))
#
print('Closing database')
dbCon.commit()
dbCon.close()
def parseDesc(text: str) -> str | None:
# Find first matching line outside {{...}}, [[...]], and block-html-comment constructs,
# and then accumulate lines until a blank one.
# Some cases not accounted for include: disambiguation pages, abstracts with sentences split-across-lines,
# nested embedded html, 'content significant' embedded-html, markup not removable with mwparsefromhell,
lines: list[str] = []
openBraceCount = 0
openBracketCount = 0
inComment = False
skip = False
for line in text.splitlines():
line = line.strip()
if not lines:
if line:
if openBraceCount > 0 or line[0] == '{':
openBraceCount += line.count('{')
openBraceCount -= line.count('}')
skip = True
if openBracketCount > 0 or line[0] == '[':
openBracketCount += line.count('[')
openBracketCount -= line.count(']')
skip = True
if inComment or line.find('<!--') != -1:
if line.find('-->') != -1:
if inComment:
inComment = False
skip = True
else:
inComment = True
skip = True
if skip:
skip = False
continue
if line[-1] == ':': # Seems to help avoid disambiguation pages
return None
if DESC_LINE_REGEX.match(line) is not None:
lines.append(line)
else:
if not line:
return removeMarkup(' '.join(lines))
lines.append(line)
if lines:
return removeMarkup(' '.join(lines))
return None
def removeMarkup(content: str) -> str:
content = EMBEDDED_HTML_REGEX.sub('', content)
content = CONVERT_TEMPLATE_REGEX.sub(convertTemplateReplace, content)
content = mwparserfromhell.parse(content).strip_code() # Remove wikitext markup
content = PARENS_GROUP_REGEX.sub('', content)
content = LEFTOVER_BRACE_REGEX.sub('', content)
return content
def convertTitle(title: str) -> str:
return html.unescape(title).replace('_', ' ')
if __name__ == '__main__':
parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
parser.parse_args()
#
genData(DUMP_FILE, DB_FILE)
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