EmulationSetEmulatedMedia is not working

[denggj28]

Rod Version: v0.107.3

The code to demonstrate your question

I am following document https://go-rod.github.io/i18n/zh-CN/#/emulation?id=%e9%85%8d%e8%89%b2%e6%96%b9%e6%a1%88%e5%92%8c%e5%aa%92%e4%bd%93

page := browser.MustPage()
_ = proto.EmulationSetEmulatedMedia{
    Media: "screen",
    Features: []*proto.EmulationMediaFeature{
        {Name: "prefers-color-scheme", Value: "dark"},
    },
}.Call(page)

What you got

But result of the following media query is false:

window.matchMedia('(prefers-color-scheme: dark)').matches

And I running my code with headless on Linux which have no any pointer devices, I try to emulate a device like this:

_ = proto.EmulationSetEmulatedMedia{
    Features: []*proto.EmulationMediaFeature{
        {Name: "any-pointer", Value: "fine"},
    },
}.Call(page)

But is not working too, media query is false:

window.matchMedia('(any-pointer: fine)').matches

[rod-robot]

Please fix the golang code in your markdown:

@@ golang markdown block 1 @@
1:1: expected 'package', found page
1:6: expected 'IDENT', found ':='
1:9: expected ';', found browser
@@ golang markdown block 2 @@
1:1: expected 'package', found _
1:3: expected 'IDENT', found '='
1:5: expected ';', found proto

_{generated by check-issue}

[ysmood]

Works fine for me:

func TestLab(t *testing.T) {
	g := setup(t)
	page := g.page

	out := page.MustEval(`() => window.matchMedia('(prefers-color-scheme: light)').matches`).Bool()

	g.True(out)

	err := proto.EmulationSetEmulatedMedia{
		Features: []*proto.EmulationMediaFeature{
			{Name: "prefers-color-scheme", Value: "dark"},
		},
	}.Call(page)
	g.E(err)

	out = page.MustEval(`() => window.matchMedia('(prefers-color-scheme: light)').matches`).Bool()

	g.False(out)
}

[denggj28]

thanks for your reply.
Your testing works, but I lanuch with headful mode, type this line in devtool console tab:

window.matchMedia('(prefers-color-scheme: dark)').matches

the result is false

and, any-pointer, any-hover, pointer, hover, whether Eval method nor devtool console tab, I can not see any effect.

[ysmood]

Could you provide the full code that can reproduce the issue like what I did?

[denggj28]

there is my demo code

package main

import (
	"fmt"
	"github.com/go-rod/rod"
	"github.com/go-rod/rod/lib/launcher"
	"github.com/go-rod/rod/lib/proto"
	"time"
)

func main() {
	URL := launcher.New().
		Set("no-sandbox").
		Set("disable-gpu").
		Headless(true).
		MustLaunch()

	browser := rod.New().
		ControlURL(URL).
		MustConnect()

	page := browser.MustPage()

	m := proto.EmulationSetEmulatedMedia{
		Features: []*proto.EmulationMediaFeature{
			{Name: "any-pointer", Value: "fine"},
			{Name: "any-hover", Value: "hover"},
		},
	}
	err := m.Call(page)
	if err != nil {
		panic(err)
	}

	output := page.MustEval(`() => window.matchMedia('(any-pointer: fine)').matches`).Bool()
	// output is false
	fmt.Println(output)

	output = page.MustEval(`() => window.matchMedia('(any-hover: hover)').matches`).Bool()
	// output is false too
	fmt.Println(output)

	page.MustNavigate("https://arh.antoinevastel.com/bots/")

	time.Sleep(5 * time.Second)

	page.MustScreenshot("")
}

and the screenshot of fingerprint

you known, my remote computer have no any pointer devices, I want to emulate a device via override media feature, but I failed.

[ysmood]

Please read rule 4 in #322.

[denggj28]

@go-rod/everyone

I have simplified my code, and build a binary, running on remote, the same problem

[ysmood]

Still, works fine for me, can you try the code below:

func TestLab(t *testing.T) {
	defaults.Show = true

	g := setup(t)
	page := g.page

	err := proto.EmulationSetEmulatedMedia{
		Features: []*proto.EmulationMediaFeature{
			{Name: "prefers-color-scheme", Value: "light"},
		},
	}.Call(page)
	g.E(err)

	out := page.MustEval(`() => window.matchMedia('(prefers-color-scheme: light)').matches`).Bool()

	g.True(out)

	err = proto.EmulationSetEmulatedMedia{
		Features: []*proto.EmulationMediaFeature{
			{Name: "prefers-color-scheme", Value: "dark"},
		},
	}.Call(page)
	g.E(err)

	out = page.MustEval(`() => window.matchMedia('(prefers-color-scheme: light)').matches`).Bool()

	g.False(out)
}

[denggj28]

I found your code works fine only use MustEval method, negative in the browser console, maybe browser changed the result.
And any-pointer, any-hover features are no effect, either MustEval method or browser console.

[ysmood]

Better to always show you test code, or modify my code, maybe you have bugs in your test code. Read the step 3 in https://github.com/go-rod/rod/blob/master/.github/ISSUE_TEMPLATE/question.md

[denggj28]

I find the same issue on Puppeteer.
puppeteer/puppeteer#5096

[ysmood]

Seems like an upstream bug.

[denggj28]

that is a bad news for anti fingerprint scan 😢