I was encountering this error when trying to set up a puppeteer instance with a proxy.

err-invalid-argument.png

I tried different approaches, but were either outdated or led me to a wrong path to try to solve my problem.

The main issue was that I tried to authenticate to the proxy with setExtraHTTPHeaders, like this:

await page.setExtraHTTPHeaders({
    'Proxy-Authorization': 'Basic ...'
});

Then I stumbled upon the following piece of chromium source code:

  // Removing headers can't make the set of pre-existing headers unsafe, but
  // adding headers can.
  if (!AreRequestHeadersSafe(modified_headers)) {
    NotifyCompleted(net::ERR_INVALID_ARGUMENT);
    // |this| may have been deleted.
    return;
  }

This indicates that some headers were modified in a "unsafe" way, which let to the net::ERR_INVALID_ARGUMENT error on chrome and in the terminal.

documentation, documentation, documentation

on pptr.de/ unfortunately nada

doc-no-results.png

Decided looking through the official puppeteer API.md and found the documentation for puppeteer.launch([options]).

Alright.


Which led me to the documentation of the supported Chromium flags.

Searching for proxy revealed this:

chromium-flags-proxy.png

Chromium flags and puppeteer

So we can use --proxy-server to specify a proxy to which the browser instance connects to.

In puppeteer this would look something like this:

...
const args = [
  '--no-sandbox',
  `--proxy-server=${PROXY_IP}`,
  ...
]

const puppeteerOptions = {
  args,
  ignoreHTTPSErrors: true,
  ...
}

const browser = await puppeteer.launch(puppeteerOptions)
const page = await browser.newPage()

That should be it if you just want to connect to a Proxy!

What about a Proxy with auth?

No problem.

You still specify the proxy IP address as above

...
const args = [
  '--no-sandbox',
  `--proxy-server=${AUTHENTICATED_PROXY_IP}`,
  ...
]

And now you simply authenticate to the page instance using page.authenticate(options).

page.authenticate.png

Note: used for HTTP Authentication

The headers WWW-Authenticate && Authorization used in HTTP Basic are essentially the same applied for proxies, just their named differently, namely Proxy-Authentication && Proxy-Authorization.

To use page.authenticate and supply proxy authorization credentials you would do something along these lines:

await page.authenticate({ username, password })

a full example

Here you go:

  • a browser instance connected to a proxy
  • a browser page (that authenticated to the proxy with username and password if needed)
  • show the current IP to verify the proxy is effectively used
const puppeteer = require('puppeteer')
const getFreeProxies = require('get-free-https-proxy')

;(async () => {
  const [proxy1] = await getFreeProxies()
  console.log('using proxy', proxy1)
  const browser = await puppeteer.launch({
    args: [
      '--no-sandbox',
      `--proxy-server=${proxy1.host}:${proxy1.port}`
    ],
    headless: false,
    ignoreHTTPSErrors: true
  })
  const page = await browser.newPage()

  // if you're using an authenticated proxy
  // await page.authenticate({ username, password })

  await page.goto('https://ipinfo.io/json')
  const content = await page.content()
  const serialized = content.substring(content.indexOf('{'), content.indexOf('}') + 1)

  console.log(JSON.parse(serialized))

  await page.waitFor(5000)
  await page.close()
  await browser.close()

  process.exit(0)
})()