BrowserConsoleLoggerProvider.cs

using Gondwana.Logging;
using Microsoft.Extensions.Logging;
 
namespace Gondwana.Blazor.Logging;

public sealed class BrowserConsoleLoggerProvider : ILoggerProvider
{
    public ILogger CreateLogger(string categoryName)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(categoryName);
        return new BrowserConsoleLogger(categoryName);
    }

    public void Dispose()
    {
    }
 
    private sealed class BrowserConsoleLogger(string categoryName) : ILogger
    {
        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;

        public bool IsEnabled(LogLevel logLevel) => logLevel != LogLevel.None;

        public void Log<TState>(
            LogLevel logLevel,
            EventId eventId,
            TState state,
            Exception? exception,
            Func<TState, Exception?, string> formatter)
        {
            ArgumentNullException.ThrowIfNull(formatter);
 
            if (!IsEnabled(logLevel))
                return;
 
            string message = formatter(state, exception);
            if (string.IsNullOrEmpty(message) && exception is null)
                return;
 
            string eventSuffix = eventId.Id != 0 || !string.IsNullOrWhiteSpace(eventId.Name)
                ? $" [{eventId.Id}:{eventId.Name ?? string.Empty}]"
                : string.Empty;
 
            string line = $"[{FormatLevel(logLevel)}] {categoryName}{eventSuffix}: {message}";
            if (exception is not null)
                line += Environment.NewLine + exception;
 
            TextWriter writer = logLevel >= LogLevel.Warning
                ? Console.Error
                : Console.Out;
            writer.WriteLine(line);
        }
 
        private static string FormatLevel(LogLevel level) => level switch
        {
            LogLevel.Trace => "trace",
            LogLevel.Debug => "debug",
            LogLevel.Information => "info",
            LogLevel.Warning => "warn",
            LogLevel.Error => "error",
            LogLevel.Critical => "critical",
            _ => level.ToString().ToLowerInvariant()
        };
    }
}

public static class BrowserConsoleLogging
{
    private const string ProviderKey = "Gondwana.Blazor.BrowserConsole";

    public static void AttachToEngineLogger()
    {
        EngineLogger.RegisterPersistentProvider(
            ProviderKey,
            static () => new BrowserConsoleLoggerProvider());
    }
}