Redirection with proxy

[MinerPL]

When trying to make a request to a page with a redirect (e.g. http -> https) undici returns me an error

TypeError: fetch failed
    at fetch (C:\Users\minerpl\IdeaProjects\MightyBot\node_modules\undici\index.js:113:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async C:\Users\minerpl\IdeaProjects\MightyBot\test-proxy.js:25:17 {
  cause: Error: Request was cancelled.

If I make a direct link from https everything works as expected. Do I need to add something to the fetch option to make it work?

[metcoder95]

While using fetch, in case of your request should expect any redirect, you need to specify to fetch what to do. in this case, you can either indicate to follow the redirect, error, or manually follow the redirection.

See: https://developer.mozilla.org/en-US/docs/Web/API/fetch

[MinerPL]

Yes, the code it tries to execute is below.

    const dispatcher = new ProxyAgent({
        uri: 'http://proxyip:proxyport/',
        auth: Buffer.from(`proxylogin:proxypassword`).toString('base64'),
    });

    const fetchOptions = {
        redirect: 'follow',
        headers: {
            'User-Agent': "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36",
            'Accept': 'text/html',
        },
        dispatcher: dispatcher instanceof ProxyAgent ? dispatcher : null,
    }

    const res = await fetch('http://google.com', fetchOptions)
        .then((res) => res.text())
        .then(console.log)
        .catch(console.error);

[metcoder95]

Can you try with Client or request instead?
I've tried to reproduce it and found it only when the Proxy server was not behaving as expected.

Although I have to admit that the fetch error is not really meaningful 🙁

[MinerPL]

Using request inside of fetch undici throw error about response status

RequestAbortedError [AbortError]: Proxy response !== 200 when HTTP Tunneling
    at Client.connect (PROJECT\node_modules\undici\lib\proxy-agent.js:93:22)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  code: 'UND_ERR_ABORTED'
}

Could the problem be that the proxies are http and not https?

[metcoder95]

Not really sure, I'm not aware of the settings for the Proxy server, it can be your proxy is not behind HTTPs, or even that the credentials are wrong. I'll suggest you look into that direction 🙂

[MinerPL]

The credentials are correct (requests that do not have a redirect work without a problem), the https itself works only the problem arises when redirecting from http to https. I'll try running a proxy on https and see if that solves the redirect problem.

[MinerPL]

After checking the proxy configuration it turned out that the proxy was the problem, the proxy server is a squid and in the default configuration it has this configuration option

# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports

After commenting it out, fetch works correctly with redirects.