Tunnel connection failed

# the proxy's answer to CONNECT, which Chrome does not show
curl -sv -o /dev/null -x http://USER:[email protected]:8000 https://example.com/ 2>&1 \
  | grep -E '^> CONNECT|^< HTTP|CONNECT tunnel failed'

# > CONNECT example.com:443 HTTP/1.1
# < HTTP/1.1 407 Proxy Authentication Required
# * CONNECT tunnel failed, response 407

import requests

PROXY = "http://USER:[email protected]:8000"

try:
    r = requests.get("https://example.com/", proxies={"http": PROXY, "https": PROXY}, timeout=30)
    print("tunnel open, the site answered", r.status_code)
except requests.exceptions.ProxyError as err:
    inner = err.args[0].reason.original_error
    print(inner)

# Tunnel connection failed: 407 Proxy Authentication Required

import scrapy
from scrapy.core.downloader.handlers.http11 import TunnelError


class TunnelSpider(scrapy.Spider):
    name = "tunnel"
    start_urls = ["https://example.com/"]

    async def start(self):
        for url in self.start_urls:
            yield scrapy.Request(url, meta={"proxy": "http://USER:[email protected]:8000"}, errback=self.on_error)

    def on_error(self, failure):
        if failure.check(TunnelError):
            self.logger.error("%s", failure.value)

# Could not open CONNECT tunnel with proxy resi.proxymonkey.io:8000 [{'status': 407, 'reason': b'Proxy Authentication Required'}]

from playwright.sync_api import Error, sync_playwright

PROXY = {"server": "http://resi.proxymonkey.io:8000", "username": "USER", "password": "PASS"}

with sync_playwright() as p:
    browser = p.chromium.launch(proxy=PROXY)
    page = browser.new_page()
    try:
        page.goto("https://example.com/")
    except Error as err:
        print("https:", err.message.splitlines()[0])
        response = page.goto("http://example.com/")
        print("http, no tunnel:", response.status, response.status_text)
    browser.close()

import { fetch, ProxyAgent } from "undici";

const dispatcher = new ProxyAgent("http://USER:[email protected]:8000");

try {
  const res = await fetch("https://example.com/", { dispatcher });
  console.log("tunnel open, the site answered", res.status);
} catch (err) {
  let e = err;
  while (e && !/Proxy response/.test(e.message ?? "")) e = e.cause;
  console.error(e ? e.message : err);
}

// Proxy response (403) !== 200 when HTTP Tunneling