--user_agent_suffix not working

[T1t4n25]

./lightpanda serve --host 127.0.0.2 --port 9222 --user_agent_suffix "(X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36"

I want to change the user agent by any means, I tried playwright python, puppeteer js, and I can't find any online guides or clarification, I tried digging into the codebase with no luck, and the only argument that gives a hint doesn't work

[krichprollsch]

Hello @T1t4n25,

We don't allo user-agent change. We only allow you to add a suffix to the existing user agent (Lightpanda/1.0).

So when you set --user_agent_suffix "(X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36" the browser will send User-Agent: Lightpanda/1.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36.

Just tested locally by requesting https://httpbin.io/get, it worked as expected:

{
  "args": {},
  "headers": {
    "Accept": [
      "*/*"
    ],
    "Accept-Encoding": [
      "deflate, gzip, br"
    ],
    "Host": [
      "httpbin.io"
    ],
    "User-Agent": [
      "Lightpanda/1.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36"
    ]
  },
  "method": "GET",
  "origin": "REDACTED:54158",
  "url": "http://httpbin.io/get"
}

[T1t4n25]

Hello @T1t4n25,

We don't allo user-agent change. We only allow you to add a suffix to the existing user agent (Lightpanda/1.0).

So when you set --user_agent_suffix "(X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36" the browser will send User-Agent: Lightpanda/1.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36.

Just tested locally by requesting https://httpbin.io/get, it worked as expected:

{
  "args": {},
  "headers": {
    "Accept": [
      "*/*"
    ],
    "Accept-Encoding": [
      "deflate, gzip, br"
    ],
    "Host": [
      "httpbin.io"
    ],
    "User-Agent": [
      "Lightpanda/1.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36"
    ]
  },
  "method": "GET",
  "origin": "REDACTED:54158",
  "url": "http://httpbin.io/get"
}

[T1t4n25]

Hi @krichprollsch
Thanks for replying, I acknowledge the feature, I tried using playwright to get the current user agent with a javascript function, it gave me the prefix without my suffix, and the result of this is being blocked from cloudflare websites that only require a valid user-agent and javascript running.

[krichprollsch]

@T1t4n25 can you share the playwright failing to set the UA please?