Cannot switch to a different thread

Question

I'm trying to create a telegram bot that can send a screenshot of a web page.

I'm using python-telegram-bot to handle telegram interactions and python-playwright to get screenshots of a page. The problem with my code is that i get the following error with Playwright:

greenlet.error: cannot switch to a different thread

This happens because i'm declaring browser = p.chromium.launch(headless=True, args=args) outside of the function that gets executed when a telegram command is called. The problem is that launching the browser every time the telegram command is called, slows my code down for about 3 seconds. How can i declare browser globally? Is it even possible?

from telegram import InlineKeyboardButton, InlineKeyboardMarkup, ParseMode
from telegram.ext import Updater, CommandHandler, ChatMemberHandler, CallbackQueryHandler
from telegram.error import Unauthorized, BadRequest
from playwright.sync_api import sync_playwright

args = [
        "--no-sandbox",
        "--disable-setuid-sandbox",
        "--use-gl=egl",
    ]

p = sync_playwright().start()
browser = p.chromium.launch(headless=True, args=args)

def start(update, context):
    page = browser.new_page()
    page.goto("https://google.com")
    page.screenshot(path="example.png")
    page.close()
    context.bot.send_photo(chat_id=update.effective_chat.id, photo=open("example.png", "rb"))  


updater = Updater('TOKEN', use_context=True, workers=124)
updater.dispatcher.add_handler(CommandHandler('start', start, run_async=True))
updater.start_polling()
updater.idle()

Answer 1

I have worked on it, and I have changed a lot in your code,

I have made a bot to try until I finish it successfully.

I have changed the code into async code.

this is the last code:

import telegram
from telegram import Update
from telegram.ext import MessageHandler, CommandHandler, Application, ContextTypes, filters
from playwright.async_api import async_playwright

args = [
        "--no-sandbox",
        "--disable-setuid-sandbox",
        "--use-gl=egl",
    ]


# Replace 'YOUR_API_TOKEN' with the API token you received from BotFather.
API_TOKEN = 'yours'


async def download_screan_shot(link="www.google.com", id_of_chat=None, update_to_use_it_to_send_the_file=None):
    file_name =f"{id_of_chat}_example.png"

    async with async_playwright() as p:
        browser = await p.chromium.launch()
        page = await browser.new_page()
        await page.goto(link)
        await page.screenshot(path=file_name)
        await browser.close()

    await update_to_use_it_to_send_the_file.message.reply_photo(file_name)



async def messages(update, context):
    the_gotten_message = update.message.text
    if "www" in the_gotten_message:
        await download_screan_shot(link=the_gotten_message, id_of_chat=update.message.from_user.id, update_to_use_it_to_send_the_file=update)
    else:
        await update.message.reply_text(update.message.text)


app = Application.builder().token(API_TOKEN).build()
app.add_handler(MessageHandler(filters.TEXT,messages))
app.run_polling()

and this is a screenshot from my bot:

I hope it works for you.

about the amount of sent links, these are failed tries.

Edit:

because you have said that you want to run the browser once, I did not find any solution for that, but I have done it using a bad idea.

it runs the browser once then saves it in public inside a list, and then uses that active browser.

this is my new code :

import telegram
from telegram import Update
from telegram.ext import MessageHandler, CommandHandler, Application, ContextTypes, filters
from playwright.async_api import async_playwright
from playwright.sync_api import sync_playwright

args = [
        "--no-sandbox",
        "--disable-setuid-sandbox",
        "--use-gl=egl",
    ]


# Replace 'YOUR_API_TOKEN' with the API token you received from BotFather.
API_TOKEN = 'yours'


opened_browser = []


async def download_screan_shot(link="www.google.com", id_of_chat=None, update_to_use_it_to_send_the_file=None):
    file_name =f"{id_of_chat}_example.png"

    # playwright = sync_playwright().start()
    # browser = playwright.chromium.launch()
    # page = browser.new_page()
    # page.goto("https://playwright.dev/")
    # page.screenshot(path="example.png")
    # browser.close()


    if (not opened_browser):
        playwright = await async_playwright().start()
        browser = await playwright.chromium.launch()
        opened_browser.append(browser)

    page = await opened_browser[0].new_page()
    await page.goto(link)
    await page.screenshot(path=file_name)
    await page.close()
    # await opened_browser[0].close()

    await update_to_use_it_to_send_the_file.message.reply_photo(file_name)



async def messages(update, context):
    the_gotten_message = update.message.text
    if "www" in the_gotten_message:
        await download_screan_shot(link=the_gotten_message, id_of_chat=update.message.from_user.id, update_to_use_it_to_send_the_file=update)
    else:
        await update.message.reply_text(update.message.text)


app = Application.builder().token(API_TOKEN).build()
app.add_handler(MessageHandler(filters.TEXT,messages))
app.run_polling()

to be honest with you, I have not seen any difference in the performance, and also I do not know what is happening there.

it is just a try, to give you an idea.

you can do the same in your code >>> I did not do that because I think you are using an old version of telegram library, and for that, I faced many errors when I tried your code with the version that I have.

tell me.