SetUserAgentOverrideAsync

[wangf205x]

I am trying to set user agent.But the following code doesn't work.

code:

using (CefSharp.DevTools.DevToolsClient dtc = this.browser.GetDevToolsClient())
{
IList brandsList = new List();
UserAgentBrandVersion uab = new UserAgentBrandVersion();
uab.Brand = "Google Chrome";
uab.Version = "89";
brandsList.Add(uab);

UserAgentBrandVersion uab2 = new UserAgentBrandVersion();
uab2.Brand = "Chromium";
uab2.Version = "89";
brandsList.Add(uab2);

UserAgentMetadata ua = new UserAgentMetadata();
ua.Brands = brandsList;
ua.Architecture = "";
ua.Model = "Nexus 7";
ua.Platform = "Android";
ua.PlatformVersion = "6.0.1";
ua.FullVersion = "89.0.4389.114";
ua.Mobile = true;

dtc.Emulation.SetUserAgentOverrideAsync("Mozilla/5.0 (Linux; Android 6.0.1; Nexus 7 Build/MOB30X) AppleWebKit/5(KHTML,likeGeckoChrome/89.0.4389.114Safari/537.36",null,null,ua);

}

Os: windows 10
Cefsharp version: 89.0.4389.114
Platform: winforms
Cpu: x86

[campersau]

If you await the SetUserAgentOverrideAsync you will see that currently an exception is thrown because it looks like ILists of DevToolsDomainEntityBase aren't currently correctly serialized and need some special handling in ToDictionary:

CefSharp/CefSharp/DevTools/DevToolsDomainEntityBase.cs

Lines 131 to 234 in 94fb457

	public IDictionary<string, object> ToDictionary()
	{
	var dict = new Dictionary<string, object>();
	var properties = GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
	foreach (var prop in properties)
	{
	var propertyAttribute = (System.Text.Json.Serialization.JsonPropertyNameAttribute)Attribute.GetCustomAttribute(prop, typeof(System.Text.Json.Serialization.JsonPropertyNameAttribute), false);
	//Only add members that have JsonPropertyNameAttribute
	if (propertyAttribute == null)
	{
	continue;
	}
	var propertyName = propertyAttribute.Name;
	var propertyRequired = Attribute.IsDefined(prop, typeof(System.Diagnostics.CodeAnalysis.DisallowNullAttribute));
	var propertyValue = prop.GetValue(this);
	if (propertyRequired && propertyValue == null)
	{
	throw new DevToolsClientException(prop.Name + " is required");
	}
	//Not required and value null, don't add to dictionary
	if (propertyValue == null)
	{
	continue;
	}
	var propertyValueType = propertyValue.GetType();
	if (typeof(DevToolsDomainEntityBase).IsAssignableFrom(propertyValueType))
	{
	propertyValue = ((DevToolsDomainEntityBase)(propertyValue)).ToDictionary();
	}
	else if (propertyValueType.IsEnum)
	{
	propertyValue = EnumToString((Enum)propertyValue);
	}
	else if(propertyValueType.IsGenericType)
	{
	var nullableType = Nullable.GetUnderlyingType(propertyValueType);
	if(nullableType != null && nullableType.IsEnum)
	{
	propertyValue = EnumToString((Enum)propertyValue);
	}
	}
	else if(propertyValueType.IsArray && propertyValueType.GetElementType().IsEnum)
	{
	propertyValue = EnumToString((Array)propertyValue);
	}
	dict.Add(propertyName, propertyValue);
	}
	return dict;
	}
	#else
	public IDictionary<string, object> ToDictionary()
	{
	var dict = new Dictionary<string, object>();
	var properties = GetType().GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
	foreach (var prop in properties)
	{
	var dataMemberAttribute = (DataMemberAttribute)Attribute.GetCustomAttribute(prop, typeof(DataMemberAttribute), false);
	//Only add members that have DataMemberAttribute
	if (dataMemberAttribute == null)
	{
	continue;
	}
	var propertyName = dataMemberAttribute.Name;
	var propertyRequired = dataMemberAttribute.IsRequired;
	var propertyValue = prop.GetValue(this);
	if (propertyRequired && propertyValue == null)
	{
	throw new DevToolsClientException(prop.Name + " is required");
	}
	//Not required and value null, don't add to dictionary
	if (propertyValue == null)
	{
	continue;
	}
	var propertyValueType = propertyValue.GetType();
	if (typeof(DevToolsDomainEntityBase).IsAssignableFrom(propertyValueType))
	{
	propertyValue = ((DevToolsDomainEntityBase)(propertyValue)).ToDictionary();
	}
	dict.Add(propertyName, propertyValue);
	}
	return dict;
	}

So currently it only works when setting UserAgentMetadata.Brands to an empty list. (Because it required and can't be null which might be wrong because here it is declared as optional https://github.com/ChromeDevTools/devtools-protocol/blob/7dd7cbb87cfb4f271d6a318364eea425f808ef15/json/browser_protocol.json#L7141.) Or leaving the UserAgentMetadata out completly and only set the userAgent string.

Complete Testcase with OffScreen Browser:

[Fact]
public async Task CanSetUserAgentOverride()
{
    using (var browser = new ChromiumWebBrowser("about:blank"))
    {
        await browser.LoadPageAsync();

        using (var devToolsClient = browser.GetDevToolsClient())
        {
            var brandsList = new List<UserAgentBrandVersion>();
            var uab = new UserAgentBrandVersion();
            uab.Brand = "Google Chrome";
            uab.Version = "89";
            brandsList.Add(uab); // comment this out to make it work

            var uab2 = new UserAgentBrandVersion();
            uab2.Brand = "Chromium";
            uab2.Version = "89";
            brandsList.Add(uab2); // comment this out to make it work

            var ua = new UserAgentMetadata();
            ua.Brands = brandsList;
            ua.Architecture = "";
            ua.Model = "Nexus 7";
            ua.Platform = "Android";
            ua.PlatformVersion = "6.0.1";
            ua.FullVersion = "89.0.4389.114";
            ua.Mobile = true;

            await devToolsClient.Emulation.SetUserAgentOverrideAsync("Mozilla/5.0 (Linux; Android 6.0.1; Nexus 7 Build/MOB30X) AppleWebKit/5(KHTML,likeGeckoChrome/89.0.4389.114Safari/537.36", null, null, ua);
        }

        await browser.LoadPageAsync("https://httpbin.org/user-agent");

        var html = await browser.GetTextAsync();
        Assert.Contains("Mozilla/5.0 (Linux; Android 6.0.1; Nexus 7 Build/MOB30X) AppleWebKit/5(KHTML,likeGeckoChrome/89.0.4389.114Safari/537.36", html);
    }
}

[amaitland]

Confirm your JavaScript works in DevTools when run using chrome.

[wangf205x]

if set userAgentData is successful,JavaScript will work

avigator.userAgentData.getHighEntropyValues(["architecture", "model", "platform", "platformVersion", "uaFullVersion"]).then(ua = >{
console.log(ua)
});

https://web.dev/user-agent-client-hints/

[amaitland]

If the userAgent is being set correctly then it's working from a CefSharp DevTools point of view.

https://web.dev/user-agent-client-hints/

https://web.dev/user-agent-client-hints/#user-agent-client-hints-from-chromium-84 suggests this is still experimental, in which version was it enabled by default? It may be that CEF requires code changes to support this.

[amaitland]

So currently it only works when setting UserAgentMetadata.Brands to an empty list. (Because it required and can't be null which might be wrong because here it is declared as optional https://github.com/ChromeDevTools/devtools-protocol/blob/7dd7cbb87cfb4f271d6a318364eea425f808ef15/json/browser_protocol.json#L7141.)

The brands property doesn't have an "optional": true when I look at the JSON for version 89.0.4389.114. So I think it's likely they've made it optional at a later point.

If I look at an older commit say https://github.com/ChromeDevTools/devtools-protocol/blob/769185f1ea71b8507e72ae245ecaaa3754c28c57/json/browser_protocol.json#L6958 then I don't see an optional value, so I'd say they made it optional in a newer version.

if set userAgentData is successful,JavaScript will work

I've merged #3487, you can grab a CI build from https://www.myget.org/gallery/cefsharp and test it out. You'll need 90.2.30-CI4006.

[wangf205x]

Thank you very much