扩展NLog加密日志

最近有个需求，要求把日志加密，因为系统一直用的是NLog，所以也只能在这个基础上加密了。本文的用法NLog很早就有了，记录下来，以作后用。

NLog加密相对好处理，只需要定义一个TargetWithLayout的子类，重写它的Write方法即可，至于加密算法，可以自己行决定，这样就可以把灵活放成最大化，有途径，不干涉。下面代码中的EncryptedFileTarget就是自定义的TargetWithLayout子类。而[Target("MyEncryptedFile")]特性，是为了在nlog.config中配置使用这个加密类。除此以外，不需要任务引用。

using NLog.Targets;

using NLog;

using NLog.Web;

using System.Security.Cryptography;

using System.Text;

using System.Reflection;

var builder = WebApplication.CreateBuilder(args);

builder.Logging.ClearProviders();

builder.Host.UseNLog();

var app = builder.Build();

var summaries = new[]

{

"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"

};

app.MapGet("/weatherforecast", () =>

{

app.Logger.LogInformation("完成测试");

var forecast = Enumerable.Range(1, 5).Select(index =>

new WeatherForecast

(

DateOnly.FromDateTime(DateTime.Now.AddDays(index)),

Random.Shared.Next(-20, 55),

summaries[Random.Shared.Next(summaries.Length)]

))

.ToArray();

return forecast;

});

app.Run();

internal record WeatherForecast(DateOnly Date, int TemperatureC, string? Summary)

{

public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);

}

[Target("MyEncryptedFile")]

public sealed class EncryptedFileTarget : TargetWithLayout

{

public string FileName { get; set; }

private string key = "bb45f81e2db4a7668d98638402e2461991785f98a89520051149c271652514ba";

protected override void Write(LogEventInfo logEvent)

{

var logMessage = this.Layout.Render(logEvent);

var encryptedMessage = Encrypt(logMessage, key);

FileName = FileName.Replace("${basedir}", Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)).Replace("${shortdate}", DateTime.Now.ToString("yyyy-MM-dd"));

System.IO.File.AppendAllText(FileName, encryptedMessage + Environment.NewLine);

}

private string Encrypt(string clearText, string key)

{

var clearBytes = Encoding.Unicode.GetBytes(clearText);

using (var encryptor = Aes.Create())

{

var saltBytes = new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 };

var pdb = new Rfc2898DeriveBytes(key, saltBytes, 1000, HashAlgorithmName.SHA256);

encryptor.Key = pdb.GetBytes(32);

encryptor.IV = pdb.GetBytes(16);

using (MemoryStream ms = new MemoryStream())

{

using (var cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))

{

cs.Write(clearBytes, 0, clearBytes.Length);

cs.Close();

}

clearText = Convert.ToBase64String(ms.ToArray());

}

}

return clearText;

}

}

下面是使用MyEncryptedFile的NLog配置文件，需要引用EncryptedFileTarget所在的命名空间，放在extensions节点中即可。

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

autoReload="true"

internalLogLevel="Info">

layout="${longdate}|${event-properties:item=EventId:whenEmpty=0}|${level:uppercase=true}|${logger}|${message} ${exception:format=tostring}" />

layout="${longdate}|${event-properties:item=EventId:whenEmpty=0}|${level:uppercase=true}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />

下面是加密后的效果：

文章来源微信公众号

想要更快更方便的了解相关知识，可以关注微信公众号