WebApi2官网学习记录---Tracing

安装追踪用的包

Install-Package Microsoft.AspNet.WebApi.Tracing
Update-Package Microsoft.AspNet.WebApi.WebHost   //-Version指定具体的版本

启用追踪的功能（在WebApiConfig.cs中）

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
           SystemDiagnosticsTraceWriter traceWriter =config.EnableSystemDiagnosticsTracing();
           traceWriter.IsVerbose = true;//显示详情信息
           traceWriter.MinimumLevel = TraceLevel.Debug;//追踪的最低级别
        }
    }

在webapi中添加追踪

using System.Web.Http.Tracing;

public class ProductsController : ApiController
{
    public HttpResponseMessage GetAllProducts()
    {
        Configuration.Services.GetTraceWriter().Info(
            Request, "ProductsController", "Get the list of products.");

        // ...
    }
}

通过实现ITraceWriter 接口自定义一个trace，也可以使用第三方的类库

public class SimpleTracer : ITraceWriter
{
    public void Trace(HttpRequestMessage request, string category, TraceLevel level, 
        Action<TraceRecord> traceAction)
    {
        TraceRecord rec = new TraceRecord(request, category, level);
        traceAction(rec);
        WriteTrace(rec);
    }

    protected void WriteTrace(TraceRecord rec)
    {
        var message = string.Format("{0};{1};{2}", 
            rec.Operator, rec.Operation, rec.Message);
        System.Diagnostics.Trace.WriteLine(message, rec.Category);
    }
}

//启用自定义的trace
public static void Register(HttpConfiguration config)
{
    config.Services.Replace(typeof(ITraceWriter), new SimpleTracer());
}

只有一个trace writer可以被激活使用，默认情况下使用一个什么都不做的trace writer。