log4net自定义追加程序依赖项 [英] log4net custom appender dependency

问题描述

我将实现一个log4net自定义附加程序. 我的附加程序工作正常，但是在重构期间，我想隔离职责，因此我需要注入一个接口. 我写了一些代码，以便您了解

I'm going to implement a log4net custom appender. My appender work fine but during refactory i want isolate the responsability, so i need to inject one interface. I write some code so you can understand

namespace WebServiceLogger.Interfaces
{
    public interface IClientService
    {
        void SendLog(string logToSend);
    }
}

这是我的Appender，现在通过邮件发送日志，但是 明天我要使用相同的附加程序将日志发送到Web服务.

This is my Appender that now send log by mail, but tomorrow i want use the same appender for send log to a web service.

using log4net.Appender;
using log4net.Core;
using WebServiceLogger.Interfaces;

namespace WebServiceLogger
{
    public class WebServiceLogAppender : AppenderSkeleton
    {
        private IClientService _clientService;

        //Url property is declared with tag in my log4net.config tag
        public string Url { get; set; }     
        public WebServiceLogAppender()
        {
            InitializeClientService(); 
        }

        protected override void Append(LoggingEvent loggingEvent)
        {
            var log = RenderLoggingEvent(loggingEvent);
            _clientService.SendLog(log);
        }

        private void InitializeClientService()
        {
            var smtpClientFactory = new SmtpClientFactory();
            var mailMessageFactory = new MailMessageFactory();
            _clientService = new EmailClientService(smtpClientFactory,mailMessageFactory)
        }
    }
}

和一个实现IClientService的类

And one class that implement IClientService

using System.Net.Mail;
using WebServiceLogger.Interfaces;

namespace WebServiceLogger
{
    public class EmailClientService : IClientService
    {
        private readonly SmtpClient _smtpClient;
        private readonly IMailMessageFactory _mailMessageFactory;

        public EmailClientService(ISmtpClientFactory smtpClientFactory, IMailMessageFactory mailMessageFactory)
        {
            _smtpClient = smtpClientFactory.Create("username", "password");
            _mailMessageFactory = mailMessageFactory;
        }

        public void SendLog(string logToSend)
        {
            var message = _mailMessageFactory.CreateMailMessage(logToSend);
            _smtpClient.Send(message);
        }
    }
}

我不希望在此类中连接Web服务，但是我只有一个无参数的构造函数.

I don't want cable the webservice inside this class but i have only a parameterless constructor.

答案是，我可以在log4net.config中指定实现IClientService接口的一个类的对象吗?

The answer is , can i specify the object of one class that implement the IClientService interface in log4net.config ?

推荐答案

由于log4net会自行创建附加程序，因此无法使用构造函数或属性注入，并且无法在config中指定类:如果可以，我真的只想在配置中指定实现IClientService的类的名称，然后在运行时创建它，但这并不可取.

Because log4net creates the appenders itself, it isn't possible to use constructor or property injection, and you cannot specify a class in the config: you could if you really wanted to just specify the name of the class implementing IClientService in the config and create it at runtime, but that's not really advisable.

如果您打算减少代码重复，那么为您的自定义记录器创建一个基类将做到这一点:然后您可以在配置文件中混合并匹配附加器.

If your intention is to reduce code duplication, then creating a base class for your custom logger will do that: then you can mix and match the appenders in your config file.

public abstract class BaseWebServiceLogAppender : AppenderSkeleton
{
    protected IClientService _clientService;

    //Url property is declared with tag in my log4net.config tag
    public string Url { get; set; }

    public BaseWebServiceLogAppender()
    {
        InitializeClientService();
    }

    protected override void Append(LoggingEvent loggingEvent)
    {
        var log = RenderLoggingEvent(loggingEvent);
        _clientService.SendLog(log);
    }

    protected abstract void InitializeClientService();
}

public class EmailWebServiceLogAppender : BaseWebServiceLogAppender
{
    protected override void InitializeClientService()
    {
        var smtpClientFactory = new SmtpClientFactory();
        var mailMessageFactory = new MailMessageFactory();
        _clientService = new EmailClientService(smtpClientFactory,mailMessageFactory)
    }
}

public class SmsWebServiceLogAppender : BaseWebServiceLogAppender
{
    protected override void InitializeClientService()
    {
        _clientService = new SmSClientService(…);
    }
}

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