What is the easier way to collect Http.Request.Headers.UserAgent in .NET 8 with Prometheus?

Question

I'm writing application in .NET 8 using Prometheus.NET.

I currently collect some standard metrics from web application with standard UseHttpMetrics() etc. I have Grafana and this is working fine.

I'm wondering what the easiest way is to collect UserAgent (what type of browser is in use of our application) information and show this info in Prometheus?

I know that I can create my own metrics and count it but maybe there is already created tool or some easier solution?

Edit: This is code from chat-gpt-4 (and it works and do what I need):

using Microsoft.AspNetCore.Http; using Prometheus; using System.Threading.Tasks;

public class UserAgentMetricsMiddleware { private static readonly Counter UserAgentCounter = Metrics.CreateCounter( "http_requests_user_agent_total", "Count of HTTP requests per User-Agent", new CounterConfiguration { LabelNames = new[] { "user_agent" } });

private readonly RequestDelegate _next;

public UserAgentMetricsMiddleware(RequestDelegate next)
{
    _next = next;
}

public async Task InvokeAsync(HttpContext context)
{
    // Capture the User-Agent header
    var userAgent = context.Request.Headers["User-Agent"].ToString() ?? "unknown";

    // Increment the counter with the User-Agent as a label
    UserAgentCounter.WithLabels(userAgent).Inc();

    await _next(context);
} }

and later register this Middleware in Program.cs after app.UseHttpMetrics();

app.UseMiddleware<UserAgentMetricsMiddleware>();