How to get user Browser name ( user-agent ) in Asp.net Core?

For me Request.Headers["User-Agent"].ToString() did't help cause returning all browsers names so found following solution.

Installed ua-parse.

In controller using UAParser;

var userAgent = HttpContext.Request.Headers["User-Agent"];
var uaParser = Parser.GetDefault();
ClientInfo c = uaParser.Parse(userAgent);

after using above code was able to get browser details from userAgent by using c.UA.Family + " " + c.UA.Major +"." + c.UA.Minor You can also get OS details like c.OS.Family;

Where c.UA.Major is a browser major version and c.UA.Minor is a browser minor version.

userAgent = Request.Headers["User-Agent"]; 

https://code.msdn.microsoft.com/How-to-get-OS-and-browser-c007dbf7 (link not live) go for 4.8

https://learn.microsoft.com/en-us/dotnet/api/system.web.httprequest.useragent?view=netframework-4.8

If you are using .net 6 or later it looks like there is a property you can use. So if you are in a controller you can access it like this:

var userAgent = HttpContext.Request.Headers.UserAgent;

Or if you are not in a controller you can inject an implementation of IHttpContextAccessor and access for example like this

using Microsoft.AspNetCore.Http;

public class MyClass
{
    public MyClass(IHttpContextAccessor httpContextAccessor)
    {
          _httpContextAccessor = httpContextAccessor;   
    }

    public string? GetUserAgent()
    {
        return _httpContextAccessor?.HttpContext?.Request.Headers.UserAgent;
    }
}

Note you will need to register IHttpContextAccessor by adding the following in your program.cs or startup.cs by adding this line of code

services.AddHttpContextAccessor();

I have developed a library to extend ASP.NET Core to support web client browser information detection at Wangkanai.Detection This should let you identity the browser name.

namespace Wangkanai.Detection
{
    /// <summary>
    /// Provides the APIs for query client access device.
    /// </summary>
    public class DetectionService : IDetectionService
    {
        public HttpContext Context { get; }
        public IUserAgent UserAgent { get; }

        public DetectionService(IServiceProvider services)
        {
            if (services == null) throw new ArgumentNullException(nameof(services));

            this.Context = services.GetRequiredService<IHttpContextAccessor>().HttpContext;
            this.UserAgent = CreateUserAgent(this.Context);
        }

        private IUserAgent CreateUserAgent(HttpContext context)
        {
            if (context == null) throw new ArgumentNullException(nameof(Context)); 

            return new UserAgent(Context.Request.Headers["User-Agent"].FirstOrDefault());
        }
    }
}

Install this .nuget package

create a class like this:

public static class YauaaSingleton
    {
        private static UserAgentAnalyzer.UserAgentAnalyzerBuilder Builder { get; }

        private static UserAgentAnalyzer analyzer = null;

        public static UserAgentAnalyzer Analyzer
        {
            get
            {
                if (analyzer == null)
                {
                    analyzer = Builder.Build();
                }
                return analyzer;
            }
        }

        static YauaaSingleton()
        {
            Builder = UserAgentAnalyzer.NewBuilder();
            Builder.DropTests();
            Builder.DelayInitialization();
            Builder.WithCache(100);
            Builder.HideMatcherLoadStats();
            Builder.WithAllFields();
        }


    }

in your controller you can read the user agent from http headers:

string userAgent = Request.Headers?.FirstOrDefault(s => s.Key.ToLower() == "user-agent").Value;

Then you can parse the user agent:

 var ua = YauaaSingleton.Analyzer.Parse(userAgent );

 var browserName = ua.Get(UserAgent.AGENT_NAME).GetValue();

you can also get the confidence level (higher is better):

 var confidence = ua.Get(UserAgent.AGENT_NAME).GetConfidence();

In production application it is important to check first if user agent exists.

public static string GetUserAgent(this HttpContext context)
{
    if (context.Request.Headers.TryGetValue(HeaderNames.UserAgent, out var userAgent))
    {
        return userAgent.ToString();
    }
    return "Not found";
}

var userAgent = $"{this.Request?.HttpContext?.Request?.Headers["user-agent"]}";

In .NET 8, I noticed that when I used Chrome or Edge, the HttpContext.Request.Headers contains the value for sec-ch-ua. However, when using Firefox, it populates the User-Agent header instead. I haven't tested this behavior in other browsers.

chromeOrEdge = Request.Headers["sec-ch-ua"];
firefox =  Request.Headers["User-Agent"];