Add backend unit tests

- Add unit testing code in backend/tests/
- Change to snake-case for script/file/directory names
- Use os.path.join() instead of '/'
- Refactor script code into function defs and a main-guard
- Make global vars all-caps

Some fixes:
- For getting descriptions, some wiki redirects weren't properly resolved
- Linked images were sub-optimally propagated
- Generation of reduced trees assumed a wiki-id association implied a description
- Tilo.py had potential null dereferences by not always using a reduced node set
- EOL image downloading didn't properly wait for all threads to end when finishing

1 files changed, 99 insertions, 0 deletions

diff --git a/backend/tol_data/enwiki/download_imgs.py b/backend/tol_data/enwiki/download_imgs.py
new file mode 100755
index 0000000..ba874e1
--- /dev/null
+++ b/backend/tol_data/enwiki/download_imgs.py
@@ -0,0 +1,99 @@
+#!/usr/bin/python3
+
+"""
+Downloads images from URLs in an image database, into an output directory,
+with names of the form 'pageId1.ext1'.
+
+SIGINT causes the program to finish an ongoing download and exit.
+The program can be re-run to continue downloading, and looks
+in the output directory do decide what to skip.
+"""
+
+# In testing, this downloaded about 100k images, over several days
+
+import re, os
+import sqlite3
+import urllib.parse, requests
+import time, signal
+
+IMG_DB = 'img_data.db' # About 130k image names
+OUT_DIR = 'imgs'
+#
+LICENSE_REGEX = re.compile(r'cc0|cc([ -]by)?([ -]sa)?([ -][1234]\.[05])?( \w\w\w?)?', flags=re.IGNORECASE)
+USER_AGENT = 'terryt.dev (terry06890@gmail.com)'
+TIMEOUT = 1
+	# https://en.wikipedia.org/wiki/Wikipedia:Database_download says to 'throttle to 1 cache miss per sec'
+	# It's unclear how to properly check for cache misses, so we just aim for 1 per sec
+
+def downloadImgs(imgDb: str, outDir: str, timeout: int) -> None:
+	if not os.path.exists(outDir):
+		os.mkdir(outDir)
+	print('Checking for already-downloaded images')
+	fileList = os.listdir(outDir)
+	pageIdsDone: set[int] = set()
+	for filename in fileList:
+		pageIdsDone.add(int(os.path.splitext(filename)[0]))
+	print(f'Found {len(pageIdsDone)}')
+	#
+	# Set SIGINT handler
+	interrupted = False
+	oldHandler = None
+	def onSigint(sig, frame):
+		nonlocal interrupted
+		interrupted = True
+		signal.signal(signal.SIGINT, oldHandler)
+	oldHandler = signal.signal(signal.SIGINT, onSigint)
+	#
+	print('Opening database')
+	dbCon = sqlite3.connect(imgDb)
+	dbCur = dbCon.cursor()
+	print('Starting downloads')
+	iterNum = 0
+	query = 'SELECT page_id, license, artist, credit, restrictions, url FROM' \
+		' imgs INNER JOIN page_imgs ON imgs.name = page_imgs.img_name'
+	for pageId, license, artist, credit, restrictions, url in dbCur.execute(query):
+		if pageId in pageIdsDone:
+			continue
+		if interrupted:
+			print('Exiting loop')
+			break
+		# Check for problematic attributes
+		if license is None or LICENSE_REGEX.fullmatch(license) is None:
+			continue
+		if artist is None or artist == '' or len(artist) > 100 or re.match(r'(\d\. )?File:', artist) is not None:
+			continue
+		if credit is None or len(credit) > 300 or re.match(r'File:', credit) is not None:
+			continue
+		if restrictions is not None and restrictions != '':
+			continue
+		# Download image
+		iterNum += 1
+		print(f'Iteration {iterNum}: Downloading for page-id {pageId}')
+		urlParts = urllib.parse.urlparse(url)
+		extension = os.path.splitext(urlParts.path)[1]
+		if len(extension) <= 1:
+			print(f'WARNING: No filename extension found in URL {url}')
+			continue
+		outFile = os.path.join(outDir, f'{pageId}{extension}')
+		print(outFile)
+		headers = {
+			'user-agent': USER_AGENT,
+			'accept-encoding': 'gzip',
+		}
+		try:
+			response = requests.get(url, headers=headers)
+			with open(outFile, 'wb') as file:
+				file.write(response.content)
+			time.sleep(timeout)
+		except Exception as e:
+			print(f'Error while downloading to {outFile}: {e}')
+			return
+	print('Closing database')
+	dbCon.close()
+
+if __name__ == '__main__':
+	import argparse
+	parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+	parser.parse_args()
+	#
+	downloadImgs(IMG_DB, OUT_DIR, TIMEOUT)