telegram-media-downloader.py

"""
Telegram Channel Media Downloader

Este script descarga archivos multimedia de un canal de Telegram especificado y evita descargar archivos ya existentes.
Las variables de configuración se leen desde un archivo `.env`.

### Instrucciones:

1. Instala las dependencias necesarias:
    pip install telethon python-dotenv

2. Crea un archivo `.env` en el mismo directorio que este script con el siguiente contenido:
    API_ID=your_api_id
    API_HASH=your_api_hash
    PHONE_NUMBER=your_phone_number
    CHANNEL_ID=your_channel_id
    SAVE_DIR=downloads
    LOG_FILE=log.txt

3. Ejecuta el script:
    python tg_downloader.py

Este script utiliza el modo sincrónico de Telethon y verifica si los archivos ya existen antes de descargarlos.
También registra todas las descargas y errores en un archivo log.
"""
import os
from telethon.sync import TelegramClient
from telethon.errors import ChannelPrivateError, ChannelInvalidError, ChatAdminRequiredError
from datetime import datetime
import sys
import time

# Function to read configuration from a file
def read_config(filename):
    config = {}
    with open(filename, 'r') as file:
        for line in file:
            name, value = line.strip().split('=')
            config[name] = value
    return config

# Read configuration
config = read_config('config.txt')

# Extract variables from config
api_id = int(config['API_ID'])
api_hash = config['API_HASH']
phone = config['PHONE_NUMBER']
channel_id = int(config['CHANNEL_ID'])
save_dir = config['SAVE_DIR']
log_file = config['LOG_FILE']

# Ensure the save directory exists
if not os.path.exists(save_dir):
    os.makedirs(save_dir)

# Initialize the Telegram client
client = TelegramClient('session_name', api_id, api_hash)

# Function to log messages
def log_message(message):
    with open(log_file, 'a') as log:
        log.write(f"{datetime.now()}: {message}\n")

# Function to download media from a message and check if the file size is correct
def download_media(message):
    if message.media:
        filename = message.file.name or f"{message.id}_{message.date.strftime('%Y-%m-%d_%H-%M-%S')}.unknown"
        file_path = os.path.join(save_dir, filename)
        
        if os.path.exists(file_path) and os.path.getsize(file_path) == message.file.size:
            print(f"Skipped (already exists and is complete): {file_path}")
            log_message(f"Skipped (already exists and is complete): {file_path}")
            return
        
        download_successful = False
        retry_count = 0
        
        while not download_successful and retry_count < 5:
            try:
                client.download_media(message.media, file_path)
                # Check if the file size matches the expected size
                if os.path.exists(file_path) and os.path.getsize(file_path) == message.file.size:
                    download_successful = True
                    print(f"\nDownloaded: {file_path}")
                    log_message(f"Downloaded: {file_path}")
                else:
                    raise Exception("File size does not match, retrying download.")
            except Exception as e:
                retry_count += 1
                error_message = f"Failed to download message ID {message.id} ({file_path}): {e}"
                print(f"\n{error_message}")
                log_message(error_message)
                if os.path.exists(file_path):
                    os.remove(file_path)  # Remove incomplete file
                
                # Progress bar with dots
                print(f"Retry {retry_count}/5. Retrying in 3 seconds...", end='', flush=True)
                time.sleep(3)
                for _ in range(3):
                    print('.', end='', flush=True)
                    time.sleep(1)
                print('')

# Main function to download all media from the channel
def main():
    client.start()
    try:
        entity = client.get_entity(channel_id)
        for message in client.iter_messages(entity):
            filename = message.file.name if message.file else "No Title"
            print(f"\nProcessing message ID {message.id} - {filename}")
            download_media(message)
    except (ChannelPrivateError, ChannelInvalidError, ChatAdminRequiredError) as e:
        error_message = f"An error occurred: {e}"
        print(error_message)
        log_message(error_message)
    except Exception as e:
        error_message = f"An unexpected error occurred: {e}"
        print(error_message)
        log_message(error_message)
    finally:
        client.disconnect()

if __name__ == '__main__':
    main()