dotnet Extensions

!Snippet Collection.md

Collection of extensions and code fragments.

Log4Net2Serilog.cs

 public static class Log4Net2Serilog
    {
        /// <summary>
        ///     Configures log4net to log to Serilog.
        /// </summary>
        /// <param name="logger">The serilog logger (if left null Log.Logger will be used).</param>
        public static void Configure(ILogger logger = null)
        {
            var serilogAppender = new SerilogAppender(logger);
            serilogAppender.ActivateOptions();
            var loggerRepository = (Hierarchy)LogManager.GetRepository(Assembly.GetCallingAssembly());
            if (loggerRepository.Root.GetAppender(serilogAppender.Name) == null)
            {
                loggerRepository.Root.AddAppender(serilogAppender);
            }
            loggerRepository.Configured = true;
        }

        private class SerilogAppender : AppenderSkeleton
        {
            private static readonly Func<SystemStringFormat, string> FormatGetter;
            private static readonly Func<SystemStringFormat, object[]> ArgumentsGetter;
            private readonly ILogger _Logger;

            static SerilogAppender()
            {
                FormatGetter = GetFieldAccessor<SystemStringFormat, string>("m_format");
                ArgumentsGetter = GetFieldAccessor<SystemStringFormat, object[]>("m_args");
            }

            public SerilogAppender(ILogger logger = null) => _Logger = logger;


            protected override void Append(LoggingEvent loggingEvent)
            {
                var source = loggingEvent.LoggerName;
                var serilogLevel = ConvertLevel(loggingEvent.Level);
                string template;
                object[] parameters = null;

                if (loggingEvent.MessageObject is SystemStringFormat systemStringFormat)
                {
                    template = FormatGetter(systemStringFormat);
                    parameters = ArgumentsGetter(systemStringFormat);
                }
                else
                {
                    template = loggingEvent.MessageObject?.ToString();
                }

                var logger = (_Logger ?? Log.Logger).ForContext(Constants.SourceContextPropertyName, source);
                logger.Write(serilogLevel, loggingEvent.ExceptionObject, template, parameters);
            }

            private static LogEventLevel ConvertLevel(Level log4NetLevel)
            {
                if (log4NetLevel == Level.Verbose)
                {
                    return LogEventLevel.Verbose;
                }
                if (log4NetLevel == Level.Debug)
                {
                    return LogEventLevel.Debug;
                }
                if (log4NetLevel == Level.Info)
                {
                    return LogEventLevel.Information;
                }
                if (log4NetLevel == Level.Warn)
                {
                    return LogEventLevel.Warning;
                }
                if (log4NetLevel == Level.Error)
                {
                    return LogEventLevel.Error;
                }
                if (log4NetLevel == Level.Fatal)
                {
                    return LogEventLevel.Fatal;
                }
                SelfLog.WriteLine("Unexpected log4net logging level ({0}) logging as Information", log4NetLevel.DisplayName);
                return LogEventLevel.Information;
            }

            //taken from http://rogeralsing.com/2008/02/26/linq-expressions-access-private-fields/
            public static Func<T, TField> GetFieldAccessor<T, TField>(string fieldName)
            {
                var param = Expression.Parameter(typeof(T), "arg");
                var member = Expression.Field(param, fieldName);
                var lambda = Expression.Lambda(typeof(Func<T, TField>), member, param);
                var compiled = (Func<T, TField>)lambda.Compile();
                return compiled;
            }
        }
    }

MemoryExtensions.cs

public static class MemoryExtensions
    {
        private static readonly List<string> ByteNames = new List<string> {"Bytes", "KB", "MB", "GB"};
        public static string ToFileSize(this int source) => Convert.ToInt64(source).ToFileSize();
        public static string ToFileSize(this long source)
        {
            const int byteConversion = 1024;
            var bytes = Math.Abs(Convert.ToDouble(source));
            var prefix = source < 0 ? "-" : "";
            for (var i = 4; i >= 0; i--)
            {
                var converted = Math.Pow(byteConversion, i);
                if (bytes >= converted)
                {
                    return $"{prefix}{Math.Round(bytes / converted, 2)} {ByteNames[i]}";
                }
            }
            return "Unknown";
        }
    }

ObservableExtensions.cs

 public static class ObservableExtensions
    {
        public static IObservable<IList<T>> SlidingWindow<T>(this IObservable<T> source, int windowSize)
        {
            var publishedSource = source.Publish().RefCount();
            return Enumerable.Range(0, windowSize)
                             .Select(skip => publishedSource.Skip(skip)).Zip();
        }
    }

SlidingWindowExtensions.cs

 public static class SlidingWindowExtensions
    {
        public static IObservable<IList<T>> SlidingWindow<T>(this IObservable<T> source, int windowSize)
        {
            var publishedSource = source.Publish().RefCount();
            return Enumerable.Range(0, windowSize)
                             .Select(skip => publishedSource.Skip(skip)).Zip();
        }
        public static IEnumerable<IList<T>> SlidingWindow<T>(this IEnumerable<T> source, int windowSize)
        {
            var window = new List<T>(windowSize);
            foreach(var line in source)
            {
                if(window.Count == windowSize)
                {
                    window.RemoveAt(0);
                }
                window.Add(line);
                if(window.Count == windowSize)
                {
                    yield return window;
                }
            }
            //return Enumerable.Range(0, source.Count()).Select(i => source.Skip(i).Take(windowSize).ToList());
        }
    }

YarnWebpack.csproj

 <Target Name="NugetRestore" BeforeTargets="Build" Condition=" !Exists('obj\project.assets.json') ">
    <Message Importance="high" Text="Restoring nuget packages..." />
    <Exec Command="nuget restore" ContinueOnError="true">
      <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
    </Exec>
    <Error Condition="'$(ErrorCode)' != '0'" Text="nuget restore failed" />
  </Target>
  <Target Name="YarnRestore" BeforeTargets="Build">
    <Exec Command="yarn --version" ContinueOnError="true">
      <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
    </Exec>
    <Error Condition="'$(ErrorCode)' != '0'" Text="yarn is required to build and run this project." />
    <Message Importance="high" Text="Restoring yarn packages..." />
    <Exec Command="yarn" ContinueOnError="true">
      <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
    </Exec>
    <Error Condition="'$(ErrorCode)' != '0'" Text="error running yarn" />
  </Target>
  <Target Name="DebugRunWebpack" BeforeTargets="Build" Condition=" '$(Configuration)' == 'Debug' ">
    <!-- Ensure Node.js is installed -->
    <Exec Command="node --version" ContinueOnError="true">
      <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
    </Exec>
    <Error Condition="'$(ErrorCode)' != '0'" Text="Node.js is required to build and run this project. To continue, please install Node.js from https://nodejs.org/, and then restart your command prompt or IDE." />
    <!-- In development, the dist files won't exist on the first run or when cloning to
         a different machine, so rebuild them if not already present. -->
    <Message Importance="high" Text="Performing first-run Webpack build..." />
    <Exec Command="node node_modules/webpack/bin/webpack.js --config webpack.config.js" />
    <Exec Command="node node_modules/webpack/bin/webpack.js" />
  </Target>
  <Target Name="PublishRunWebpack" AfterTargets="ComputeFilesToPublish">
    <!-- As part of publishing, ensure the JS resources are freshly built in production mode -->
    <Exec Command="node node_modules/webpack/bin/webpack.js --config webpack.config.js --env.prod" />
    <Exec Command="node node_modules/webpack/bin/webpack.js --env.prod" />
    <!-- Include the newly-built files in the publish output -->
    <ItemGroup>
      <DistFiles Include="wwwroot\dist\**" />
      <ResolvedFileToPublish Include="@(DistFiles->'%(FullPath)')" Exclude="@(ResolvedFileToPublish)">
        <RelativePath>%(DistFiles.Identity)</RelativePath>
        <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
      </ResolvedFileToPublish>
    </ItemGroup>
  </Target>