lateximgbot

commit e601e56875e889ee166a278df668ca3c912042cf
Author: torresjrjr <b.torres.edu@gmail.com>
Date:   Wed, 11 Mar 2020 20:27:42 +0000

Initial commit

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.gitignore
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README.md
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bot.py
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diff --git a/.gitignore b/.gitignore
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+token
diff --git a/README.md b/README.md
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+# Latex Image Bot
+
+A Telegram bot that returns rendered LaTeX images.
+
+Bot: t.me/LatexImgBot
+Author: t.me/torresjrjr
diff --git a/bot.py b/bot.py
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+#!/usr/bin/python
+"""
+This is a Telegram Bot which returns rendered images of LaTeX with an API.
+"""
+
+import telegram
+from telegram.ext import Updater, MessageHandler, CommandHandler, Filters
+import requests
+import urllib
+import logging
+
+logging.basicConfig(
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+    level=logging.INFO,
+)
+
+
+# constants
+
+try:
+    with open('token') as File:
+        TOKEN = File.read().splitlines()[0]
+except FileNotFoundError as Err:
+    print(
+"""
+You need a bot token to run this Telegram bot. Please make a
+file named 'token' with your bot token in there, in the same
+folder as your bot file.
+
+Learn more at t.me/botfather
+""" )
+    quit()
+
+API = "https://latex.codecogs.com/png.latex?" 
+EXAMPLE_LATEX = r"x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}"
+
+
+# callback handlers
+
+def cb_start(upd, ctx):
+    first_name = upd.message.from_user.first_name
+    upd.message.reply_text(
+        f"Hello, {first_name}\n"
+        "Type some _LaTeX_ and this bot will "
+        "return a rendered image of it.\n\n"
+
+        "Use   /link (_with some LaTeX_)   to also return an image link.\n\n"
+
+        "This bot will support inline queries in the future.\n\n"
+
+        "Try the following:\n"
+        "```\n"
+        f"{EXAMPLE_LATEX}\n"
+        "```\n\n"
+
+        "Author: t.me/torresjrjr",
+
+        parse_mode=telegram.ParseMode.MARKDOWN,
+    )
+
+
+def cb_help(upd, ctx):
+    cb_start(upd, ctx)
+
+
+def cb_echo(upd, ctx):
+    ctx.bot.send_message(
+        chat_id = upd.effective_chat.id,
+        text    = upd.message.text,
+    )
+
+
+def handler(upd, ctx, kind="standard"):
+    msg = upd.message.text
+    print("Incomming message:", msg)
+
+    if kind == "linked": latex = msg[5:]  # remove the "/link" part
+    else:                latex = msg
+
+    encoded_latex = urllib.parse.quote(latex)
+    latex_url = API + encoded_latex
+
+    if kind == "standard": caption = f"`{msg}`"
+    elif kind == "linked": caption = f"`{msg}`" + "\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="linked")
+cb_handler = lambda upd, ctx: handler(upd, ctx)
+
+
+# main
+
+def main():
+    print("Running...")
+    updater = Updater(TOKEN, use_context=True)
+
+    dp = updater.dispatcher
+    dp.add_handler(CommandHandler('start'     , cb_start))
+    dp.add_handler(CommandHandler('help'      , cb_help))
+    dp.add_handler(CommandHandler('link'      , cb_link))
+    dp.add_handler(MessageHandler(Filters.text, cb_handler))
+
+    updater.start_polling()
+    updater.idle()
+    print("Done.")
+
+
+if __name__=='__main__':
+    main()