lateximgbot

bot.py (6356B)

---

 #!/usr/bin/python
 """
 This is a Telegram Bot which returns rendered images of LaTeX using an API.
 """
 
 import telegram
 from telegram.ext import Updater, MessageHandler, CommandHandler, Filters
 from telegram.error import (TelegramError, Unauthorized, BadRequest, 
                             TimedOut, ChatMigrated, NetworkError)
 import datetime
 import urllib
 import logging
 import os
 import signal
 import random
 
 logging.basicConfig(
     filename="log", filemode='a',
     format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
     level=logging.INFO,
 )
 
 
 # CONSTANTS
 
 VERSION = "0.0.1"
 
 try:
     with open('token') as TokenFile:
         TOKEN = TokenFile.read().splitlines()[0]
 except FileNotFoundError:
     print(
 """
 You need a bot token to run an instance of this Telegram bot.
 Please make a file named 'token' with your bot token in there,
 in the same folder as this bot file.
 
 Learn more at t.me/botfather
 """ )
     quit()
 
 IMAGE_TYPE = "png"
 IMAGE_DPI  = "512"
 API = f"https://latex.codecogs.com/{IMAGE_TYPE}.latex?%%5C{IMAGE_DPI}dpi%%20%s"
 EXAMPLE_LATEX = r"\text{The quadratic formula} \\ " + "\n" + \
                 r"x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}"
 
 
 # UTIL
 
 # Returns a iso-formatted string of datetime at moment of call.
 dt_now = lambda: datetime.datetime.now().isoformat(timespec="seconds")
 
 def logger_dec(old_cb_func):
 
     def new_cb_func(upd, ctx):
         msg     = upd.message.text
         name    = upd.message.from_user.name
         log_msg = f"{name}\t:: {msg}"
         logging.info(log_msg)
         print(log_msg)
 
         return old_cb_func(upd, ctx)
 
     return new_cb_func
 
 
 def get_random_example():
     example_lines  = []
     recording      = False
 
     with open("examples.tex", 'r') as File:
         line = next(File)
         if not line.startswith("%TOTAL"):
             raise Exception("No '%TOTAL N' on first line of examples.tex")
         else:
             total_examples = int( line.split()[1] )
             example_number = random.randint(1, total_examples)
 
         for line in File:
             if line.startswith(f"%BEGIN {example_number}"):
                 recording = True
                 continue
 
             if line.startswith("%END") and recording:
                 recording = False
                 break
 
             if recording:
                 example_lines += [line]
 
     example = ''.join(example_lines)
     return example
 
 
 # CALLBACK HANDLERS
 
 @logger_dec
 def cb_start(upd, ctx):
     bot_username = ctx.bot.get_me().username.replace('_', '\\_')
 
     # outgoing text
     out_msg = f"""\
 @{bot_username} renders _LaTeX_ text and formulae.
 
 Try:  `\\texttt{{Hello, world!}}`
 
 See /random for examples
 See /help for more
 See /about
 """
 
     # send message
     upd.message.reply_text(
         out_msg,
         parse_mode=telegram.ParseMode.MARKDOWN,
     )
 
 
 def cb_help(upd, ctx):
     cb_start(upd, ctx)
 
 
 @logger_dec
 def cb_about(upd, ctx):
     """
     /about callback
     """
     bot_username = ctx.bot.get_me().username.replace('_', '\\_')
 
     # Outgoing text
     out_msg = f"""\
 @{bot_username} (@LatexImgBot\_updates)
 
 Version
     {VERSION}
 Source code
     https://sr.ht/~torresjrjr/linkchanbot
 Maintainer
     @torresjrjr <b@torresjrjr.com>
 License
     GNU Affero General Public License
 """
 
     # Send message
     upd.message.reply_text(
         out_msg,
         parse_mode=telegram.ParseMode.MARKDOWN,
     )
 
 
 @logger_dec
 def cb_random(upd, ctx):
     latex = get_random_example()
 
     encoded_latex = urllib.parse.quote(latex)
     latex_url     = API % encoded_latex
 
     caption = f"`{latex}`"
 
     ctx.bot.send_photo(
         chat_id    = upd.effective_chat.id,
         photo      = latex_url,
         caption    = caption,
         parse_mode = telegram.ParseMode.MARKDOWN,
     )
 
 
 @logger_dec
 def handler(upd, ctx, kind="standard"):
     msg = upd.message.text
 
     if kind == "link": latex = msg.replace("/link","")
     else             : latex = msg
 
     encoded_latex = urllib.parse.quote(latex)
     latex_url     = API % encoded_latex
 
     if   kind == "standard": caption = f"`{latex}`"
     elif kind == "link"    : caption = f"`{latex}`\n" + latex_url
 
     ctx.bot.send_photo(
         chat_id    = upd.effective_chat.id,
         photo      = latex_url,
         caption    = caption,
         parse_mode = telegram.ParseMode.MARKDOWN,
     )
 
 
 cb_link    = lambda upd, ctx: handler(upd, ctx, kind="link")
 cb_handler = lambda upd, ctx: handler(upd, ctx)
 
 @logger_dec
 def cb_admin(upd, ctx):
     msg     = upd.message.text
     name    = upd.message.from_user.name
     log_msg = f"{name}\t:: {msg}"
     print(log_msg)
 
     username = upd.message.from_user.username
     if username == "torresjrjr":
         upd.message.reply_text(
             "Admin authorised. Sending SIGINT...",
             parse_mode=telegram.ParseMode.MARKDOWN,
         )
         os.kill(os.getpid(), signal.SIGINT)
 
 
 def cb_error(update, context):
     try:
         raise context.error
     except Unauthorized as e:
         print("Unauthorized Error:", e)  # remove update.message.chat_id from conversation list
     except BadRequest as e:
         print("BadRequest Error:", e)  # handle malformed requests - read more below!
     except TimedOut as e:
         print("TimedOut Error:", e)  # handle slow connection problems
     except NetworkError as e:
         print("NetworkError Error:", e)  # handle other connection problems
     except ChatMigrated as e:
         print("ChatMigrated Error:", e)  # the chat_id of a group has changed, use e.new_chat_id instead
     except TelegramError as e:
         print("TelegramError Error:", e)  # handle all other telegram related errors
 
 
 # MAIN
 
 def main():
     print("Starting bot...")
 
     updater = Updater(TOKEN, use_context=True)
 
     dp = updater.dispatcher
     dp.add_error_handler(cb_error)
     dp.add_handler(CommandHandler('start'     , cb_start))
     dp.add_handler(CommandHandler('help'      , cb_help))
     dp.add_handler(CommandHandler('about'     , cb_about))
     dp.add_handler(CommandHandler('link'      , cb_link))
     dp.add_handler(CommandHandler('random'    , cb_random))
     dp.add_handler(CommandHandler('admin'     , cb_admin))
     dp.add_handler(MessageHandler(Filters.text, cb_handler))
 
     print(dt_now(), "Serving...")
 
     updater.start_polling()
     updater.idle()
 
     print(dt_now(), "Ended.")
 
 
 if __name__=='__main__':
     main()