Telegram bot fails to send PDF document with HTTP URL error

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1

I’m having trouble with my Telegram bot when trying to send a PDF file. Every time I attempt to send the document, I get this error message: aiogram.exceptions.TelegramBadRequest: Telegram server says - Bad Request: failed to get HTTP URL content

Here’s my code that handles photo processing and PDF generation:

import os
import uuid
import asyncio
from aiogram import Router, F, Bot
from aiogram.filters import CommandStart
from aiogram.types import Message
from gradio_client import Client, handle_file

msg_router = Router()

def process_math_question(file_path):
    ai_client = Client("Qwen/Qwen2-Math-Demo")
    response = ai_client.predict(
        image=handle_file(file_path),
        sketchpad={
            "background": handle_file(
                'https://raw.githubusercontent.com/gradio-app/gradio/main/test/test_files/bus.png'),
            "layers": [],
            "composite": None
        },
        question="solve this, answer in LaTex format",
        api_name="/math_chat_bot"
    )
    return response

@msg_router.message(CommandStart())
async def start_command(msg: Message):
    await msg.answer("Hello there!")

@msg_router.message(F.photo)
async def handle_photo(msg: Message, telegram_bot: Bot):
    temp_image = f"{uuid.uuid4()}.png"
    
    file_data = await telegram_bot.get_file(msg.photo[-1].file_id)
    await telegram_bot.download_file(file_data.file_path, destination=temp_image)
    
    await msg.answer("Processing your request...")
    
    math_result = await asyncio.to_thread(process_math_question, temp_image)
    output_file = f"{uuid.uuid4()}.tex"
    
    with open(output_file, "w") as tex_file:
        tex_file.write(f"{math_result}")
    
    os.system('bash convert_script.sh')
    await msg.answer_document("output.pdf")
    
    os.remove(temp_image)
    os.remove(output_file)
    os.remove("output.tex")

I tried using msg.answer_document("filename") but it doesn’t work. The PDF file gets created successfully by the bash script, but sending it through the bot fails. What could be causing this issue?

2

try using FSInputFile instead of just passing the string path. something like await msg.answer_document(FSInputFile('output.pdf')) - worked for me when i had same issue with pdf sending. also double check your bash script isnt changing working directory

3

Had this exact problem last month and it drove me crazy for hours. The issue is probably timing related - your bash script might still be running when you try to send the PDF. I noticed you’re not waiting for the bash script to complete before calling answer_document. Try replacing os.system('bash convert_script.sh') with subprocess.run(['bash', 'convert_script.sh'], check=True) to ensure it finishes properly. Also worth adding a small delay with await asyncio.sleep(1) after the script runs, just to be safe. Another thing that caught me out was file permissions - make sure your bot process has read access to the generated PDF. You can verify this by adding a print statement to check the file size before sending it.

4

This error typically occurs when the bot tries to access a file that doesn’t exist at the specified path or lacks proper permissions. Looking at your code, I suspect the issue is with file path handling. You’re creating files with UUID names but then referencing ‘output.pdf’ directly in the answer_document call. I had a similar problem with my bot where the bash script was creating files in a different directory than expected. Try using absolute file paths and verify the PDF actually exists before sending it. Add a quick check like ‘if os.path.exists(“output.pdf”):’ before the answer_document line. Also consider using InputFile from aiogram.types for better file handling - it gives you more control over the file object being sent. Make sure your convert_script.sh is actually producing the output.pdf file in the correct location where your Python script expects it.