1 files changed, 126 insertions, 0 deletions
diff --git a/backend/hist_data/enwiki/gen_desc_data.py b/backend/hist_data/enwiki/gen_desc_data.py
new file mode 100755
index 0000000..b3fde52
--- /dev/null
+++ b/backend/hist_data/enwiki/gen_desc_data.py
@@ -0,0 +1,126 @@
+#!/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 sys, os, re
+import bz2
+import html, mwxml, mwparserfromhell
+import sqlite3
+
+DUMP_FILE = 'enwiki-20220501-pages-articles-multistream.xml.bz2' # Had about 22e6 pages
+DB_FILE = 'desc_data.db'
+
+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__':
+	import argparse
+	parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+	parser.parse_args()
+	#
+	genData(DUMP_FILE, DB_FILE)