import aiohttp
from aiohttp import web
from urllib.parse import urlparse

async def proxy_handler(request):
    # Retrieve the URL from the query parameters
    target_url = request.query.get('url')
    if not target_url:
        return web.Response(status=400, text="Missing 'url' query parameter.")

    # Optional: Validate the URL schema
    parsed_url = urlparse(target_url)
    if parsed_url.scheme not in ['http', 'https']:
        return web.Response(status=400, text="Invalid URL scheme. Only HTTP and HTTPS are supported.")

    # Get the aiohttp ClientSession from the app
    session = request.app['session']

    # Prepare the request headers, removing the host header
    headers = dict(request.headers)
    headers.pop('Host', None)

    # Forward the request to the target URL
    async with session.request(
        method=request.method,
        url=target_url,
        headers=headers,
        allow_redirects=False,
        data=await request.read()  # Forward the original payload as it is
    ) as response:
        # Prepare the response headers, excluding 'Transfer-Encoding' and 'Content-Encoding'
        response_headers = {k: v for k, v in response.headers.items() if k.lower() not in ['transfer-encoding', 'content-encoding']}

        # Create a new aiohttp response
        return web.Response(
            status=response.status,
            headers=response_headers,
            body=await response.read()
        )

async def create_session(app):
    app['session'] = aiohttp.ClientSession()

async def close_session(app):
    await app['session'].close()

app = web.Application()
app.add_routes([web.route('*', '/', proxy_handler)])

app.on_startup.append(create_session)
app.on_cleanup.append(close_session)

if __name__ == '__main__':
    web.run_app(app, port=8080)  # Specify the port to run on