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#!/usr/bin/python3
"""
For some set of page IDs, looks up their content in the wiki dump,
and tries to parse infobox image names, storing them into a database.
The program can be re-run with an updated set of page IDs, and
will skip already-processed page IDs.
"""
import argparse
import os
import re
import bz2
import html
import urllib.parse
import sqlite3
DUMP_FILE = 'enwiki-20220501-pages-articles-multistream.xml.bz2'
INDEX_DB = 'dump_index.db'
IMG_DB = 'img_data.db' # The database to create
DB_FILE = os.path.join('..', 'data.db')
ID_LINE_REGEX = re.compile(r'<id>(.*)</id>')
IMG_LINE_REGEX = re.compile(r'.*\| *image *= *([^|]*)')
BRACKET_IMG_REGEX = re.compile(r'\[\[(File:[^|]*).*]]')
IMG_NAME_REGEX = re.compile(r'.*\.(jpg|jpeg|png|gif|tiff|tif)', flags=re.IGNORECASE)
CSS_IMG_CROP_REGEX = re.compile(r'{{css image crop\|image *= *(.*)', flags=re.IGNORECASE)
# ========== For data generation ==========
def genData(pageIds: set[int], dumpFile: str, indexDb: str, imgDb: str) -> None:
""" Looks up page IDs in dump and creates database """
print('Opening databases')
indexDbCon = sqlite3.connect(indexDb)
indexDbCur = indexDbCon.cursor()
imgDbCon = sqlite3.connect(imgDb)
imgDbCur = imgDbCon.cursor()
print('Checking tables')
if imgDbCur.execute('SELECT name FROM sqlite_master WHERE type="table" AND name="page_imgs"').fetchone() is None:
# Create tables if not present
imgDbCur.execute('CREATE TABLE page_imgs (page_id INT PRIMARY KEY, title TEXT UNIQUE, img_name TEXT)')
# 'img_name' values are set to NULL to indicate page IDs where no image was found
imgDbCur.execute('CREATE INDEX page_imgs_idx ON page_imgs(img_name)')
else: # Check for already-processed page IDs
numSkipped = 0
for (pid,) in imgDbCur.execute('SELECT page_id FROM page_imgs'):
if pid in pageIds:
pageIds.remove(pid)
numSkipped += 1
else:
print(f'Found already-processed page ID {pid} which was not in input set')
print(f'Will skip {numSkipped} already-processed page IDs')
print('Getting dump-file offsets')
offsetToPageId: dict[int, list[int]] = {}
offsetToEnd: dict[int, int] = {} # Maps chunk-start offsets to their chunk-end offsets
pageIdToTitle: dict[int, str] = {}
iterNum = 0
for pageId in pageIds:
iterNum += 1
if iterNum % 1e4 == 0:
print(f'At iteration {iterNum}')
query = 'SELECT offset, next_offset, title FROM offsets WHERE id = ?'
row = indexDbCur.execute(query, (pageId,)).fetchone()
if row is None:
print(f'WARNING: Page ID {pageId} not found')
continue
chunkOffset, endOffset, title = row
offsetToEnd[chunkOffset] = endOffset
if chunkOffset not in offsetToPageId:
offsetToPageId[chunkOffset] = []
offsetToPageId[chunkOffset].append(pageId)
pageIdToTitle[pageId] = title
print(f'Found {len(offsetToEnd)} chunks to check')
print('Iterating through chunks in dump file')
with open(dumpFile, mode='rb') as file:
iterNum = 0
for pageOffset, endOffset in offsetToEnd.items():
iterNum += 1
if iterNum % 100 == 0:
print(f'At iteration {iterNum}')
chunkPageIds = offsetToPageId[pageOffset]
# Jump to chunk
file.seek(pageOffset)
compressedData = file.read(None if endOffset == -1 else endOffset - pageOffset)
data = bz2.BZ2Decompressor().decompress(compressedData).decode()
# Look in chunk for pages
lines = data.splitlines()
lineIdx = 0
while lineIdx < len(lines):
# Look for <page>
if lines[lineIdx].lstrip() != '<page>':
lineIdx += 1
continue
# Check page id
lineIdx += 3
idLine = lines[lineIdx].lstrip()
match = ID_LINE_REGEX.fullmatch(idLine)
if match is None or int(match.group(1)) not in chunkPageIds:
lineIdx += 1
continue
pageId = int(match.group(1))
lineIdx += 1
# Look for <text> in <page>
foundText = False
while lineIdx < len(lines):
if not lines[lineIdx].lstrip().startswith('<text '):
lineIdx += 1
continue
foundText = True
# Get text content
content: list[str] = []
line = lines[lineIdx]
content.append(line[line.find('>') + 1:])
lineIdx += 1
foundTextEnd = False
while lineIdx < len(lines):
line = lines[lineIdx]
if not line.endswith('</text>'):
content.append(line)
lineIdx += 1
continue
foundTextEnd = True
content.append(line[:line.rfind('</text>')])
# Look for image-filename
imageName = getImageName(content)
imgDbCur.execute(
'INSERT into page_imgs VALUES (?, ?, ?)',
(pageId, None if imageName is None else pageIdToTitle[pageId], imageName))
break
if not foundTextEnd:
print(f'WARNING: Did not find </text> for page id {pageId}')
break
if not foundText:
print(f'WARNING: Did not find <text> for page id {pageId}')
print('Closing databases')
indexDbCon.close()
imgDbCon.commit()
imgDbCon.close()
def getImageName(content: list[str]) -> str | None:
""" Given an array of text-content lines, tries to return an infoxbox image name, or None """
# Note: Doesn't try and find images in outside-infobox [[File:...]] and <imagemap> sections
for line in content:
match = IMG_LINE_REGEX.match(line)
if match is not None:
imageName = match.group(1).strip()
if imageName == '':
return None
imageName = html.unescape(imageName)
# Account for {{...
if imageName.startswith('{'):
match = CSS_IMG_CROP_REGEX.match(imageName)
if match is None:
return None
imageName = match.group(1)
# Account for [[File:...|...]]
if imageName.startswith('['):
match = BRACKET_IMG_REGEX.match(imageName)
if match is None:
return None
imageName = match.group(1)
# Account for <!--
if imageName.find('<!--') != -1:
return None
# Remove an initial 'File:'
if imageName.startswith('File:'):
imageName = imageName[5:]
# Remove an initial 'Image:'
if imageName.startswith('Image:'):
imageName = imageName[6:]
# Check for extension
match = IMG_NAME_REGEX.match(imageName)
if match is not None:
imageName = match.group(0)
imageName = urllib.parse.unquote(imageName)
imageName = html.unescape(imageName) # Intentionally unescaping again (handles some odd cases)
imageName = imageName.replace('_', ' ')
return imageName
# Exclude lines like: | image = <imagemap>
return None
return None
# ========== For getting input page IDs ==========
def getInputPageIdsFromDb(dbFile: str, indexDb: str) -> set[int]:
print('Getting event data')
titles: set[str] = set()
dbCon = sqlite3.connect(dbFile)
for (title,) in dbCon.execute('SELECT title from events'):
titles.add(title)
dbCon.close()
print('Getting page IDs')
pageIds: set[int] = set()
dbCon = sqlite3.connect(indexDb)
dbCur = dbCon.cursor()
for title in titles:
row = dbCur.execute('SELECT id FROM offsets WHERE title = ?', (title,)).fetchone()
if row:
pageIds.add(row[0])
dbCon.close()
print(f'Result: {len(pageIds)} out of {len(titles)}')
return pageIds
# ========== Main block ==========
if __name__ == '__main__':
parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
parser.parse_args()
pageIds = getInputPageIdsFromDb(DB_FILE, INDEX_DB)
genData(pageIds, DUMP_FILE, INDEX_DB, IMG_DB)
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