Add optional progress bar and basic logging

Dockerfile

@@ -1,7 +1,7 @@
 FROM python:3.7-alpine3.14
 RUN \
 	apk add --no-cache gcc libc-dev libffi-dev \
-	&& pip install --no-cache-dir telethon 'cryptg<0.3'
+	&& pip install --no-cache-dir telethon 'cryptg<0.3' tqdm
 COPY telegram-dl.py /
 VOLUME ["/data/"]
 WORKDIR /data

README.md

@@ -4,7 +4,9 @@ Usage: `telegram-dl.py URL [URL...]`
 
 All URLs must be messages in the same channel. The output consists of writing each message to a file `{channelName}_{messageId}.json`. If the message has any attachment (photo, video, file, etc.), it gets downloaded as well. The filename for that is chosen by Telethon; if it's a file attachment, the literal path as presented by Telegram is used, and if it's a photo or video, a name is made up.
 
-The only dependency of the script is Telethon (though you probably want cryptg for performance reasons). For authentication (always required), specify the `TELEGRAM_API_ID`, `TELEGRAM_API_HASH`, and `TELEGRAM_BOT_TOKEN` environment variables. The session is stored in a file `telegram-dl.session`; keeping this between executions is not critical but recommended.
+The only mandatory dependency of the script is Telethon. You probably want cryptg as well for performance reasons when downloading larger files. With tqdm installed, you get a progress bar for each download.
+
+For authentication (always required), specify the `TELEGRAM_API_ID`, `TELEGRAM_API_HASH`, and `TELEGRAM_BOT_TOKEN` environment variables. The session is stored in a file `telegram-dl.session`; keeping this between executions is not critical but recommended.
 
 A `Dockerfile` is provided for running with Docker. Simply provide the URL(s) as arguments on running the image. Data is written to the `/data` volume, which you may want to mount from the host machine instead.
 

telegram-dl.py

@@ -2,11 +2,16 @@
 import asyncio
 import base64
 import datetime
+import functools
 import json
 import os
 import re
 import sys
 import telethon
+try:
+	import tqdm
+except ImportError:
+	tqdm = None
 
 
 API_ID = os.environ['TELEGRAM_API_ID']
@@ -23,6 +28,13 @@ def stuff_to_json(o):
 	raise TypeError(f'Object of type {type(o)} is not JSON serializable')
 
 
+def download_callback(current, total, bar = None):
+	if bar is None:
+		return
+	bar.total = total  #FIXME: Accesses undocumented attribute of tqdm
+	bar.update(current - bar.n)  #FIXME: https://github.com/tqdm/tqdm/issues/1264
+
+
 async def main():
 	# Parse URLs
 	targets = []
@@ -43,15 +55,26 @@ async def main():
 
 	# Let's go...
 	client = telethon.TelegramClient('telegram-dl', API_ID, API_HASH)
+	print('Connecting', file = sys.stderr)
 	await client.start(bot_token = BOT_TOKEN)
+	print('Fetching messages', file = sys.stderr)
 	messages = await client.get_messages(channelName, ids = ids)
 	for message in messages:
 		if not message:
 			continue
+		print(f'Processing message {message.id}', file = sys.stderr)
 		with open(f'{channelName}_{message.id}.json', 'x') as fp:
 			json.dump(message.to_dict(), fp, default = stuff_to_json)
 
-		await client.download_media(message)
+		if message.media and tqdm:
+			bar = tqdm.tqdm(unit = 'iB', unit_divisor = 1024, unit_scale = True)
+		else:
+			bar = None
+		try:
+			await client.download_media(message, progress_callback = functools.partial(download_callback, bar = bar))
+		finally:
+			if bar is not None:
+				bar.close()
 
 
 asyncio.run(main())