背景

上回提到开发web api的时候，一般是需要记录api的输入输出信息，方便后续排查问题；使用的是委托的形式进行记录日志。

使用Func<T, TResult> 委托实现API日志的记录

这次我们使用另外一种方式，Filter来记录输入输出日志。

实现方式

1、首先在进入action的时候，定义OnActionExecuting。

    public override void OnActionExecuting(ActionExecutingContext context){base.OnActionExecuting(context);// 后续添加了获取请求的请求体，如果在实际项目中不需要删除即可long contentLen = context.HttpContext.Request.ContentLength == null ? 0 : context.HttpContext.Request.ContentLength.Value;if (contentLen > 0){// 读取请求体中所有内容System.IO.Stream stream = context.HttpContext.Request.Body;if (context.HttpContext.Request.Method == "POST"){stream.Position = 0;}byte[] buffer = new byte[contentLen];stream.Read(buffer, 0, buffer.Length);// 转化为字符串RequestBody = System.Text.Encoding.UTF8.GetString(buffer);}ActionArguments = Newtonsoft.Json.JsonConvert.SerializeObject(context.ActionArguments);Stopwatch = new Stopwatch();Stopwatch.Start();}

2、定义Stopwatch ，计算方法的耗时。

  private string ActionArguments { get; set; }/// <summary>/// 请求体中的所有值/// </summary>private string RequestBody { get; set; }private Stopwatch Stopwatch { get; set; }

3、结束的时候，把信息打印出来OnActionExecuted。

  public override void OnActionExecuted(ActionExecutedContext context){base.OnActionExecuted(context);Stopwatch.Stop();string url = context.HttpContext.Request.Host + context.HttpContext.Request.Path + context.HttpContext.Request.QueryString;string method = context.HttpContext.Request.Method;string controller = context.Controller.ToString();string action = context.ActionDescriptor.DisplayName;string token = "";if (context.HttpContext.Request != null && context.HttpContext.Request.Headers != null && context.HttpContext.Request.Headers["Authorization"].Count > 0){token = context.HttpContext.Request.Headers["Authorization"];}string qs = ActionArguments;dynamic result = context?.Result?.GetType()?.Name == "EmptyResult" ? new { Value = "无返回结果" } : context?.Result as dynamic;string res = "在返回结果前发生了异常";try{if (result != null){res = Newtonsoft.Json.JsonConvert.SerializeObject(result.Value);}}catch (System.Exception){res = "日志未获取到结果，返回的数据无法序列化";}NLogger.Info($"地址：{url} \n " +$"controller：{controller} \n " +$"action：{action} \n " +$"token：{token} \n " +$"方式：{method} \n " +$"请求体：{RequestBody} \n " +$"参数：{qs}\n " +$"结果：{res}\n " +$"耗时：{Stopwatch.Elapsed.TotalMilliseconds} 毫秒（指控制器内对应方法执行完毕的时间）");}

4、控制器调用LogAttribute。

/// <summary>////// </summary>[Produces("application/json")][LogAttribute][CustomExceptionFilterAttribute]public class DefaultController : Controller{}

完整代码

using CompanyName.ProjectName.Core;
using Microsoft.AspNetCore.Mvc.Filters;
using System.Diagnostics;namespace CompanyName.ProjectName.HttpApi.Host.Code
{/// <summary>/// 拦截器/// </summary>public class LogAttribute : ActionFilterAttribute{private string ActionArguments { get; set; }/// <summary>/// 请求体中的所有值/// </summary>private string RequestBody { get; set; }private Stopwatch Stopwatch { get; set; }/// <summary>////// </summary>/// <param name="context"></param>public override void OnActionExecuting(ActionExecutingContext context){base.OnActionExecuting(context);// 后续添加了获取请求的请求体，如果在实际项目中不需要删除即可long contentLen = context.HttpContext.Request.ContentLength == null ? 0 : context.HttpContext.Request.ContentLength.Value;if (contentLen > 0){// 读取请求体中所有内容System.IO.Stream stream = context.HttpContext.Request.Body;if (context.HttpContext.Request.Method == "POST"){stream.Position = 0;}byte[] buffer = new byte[contentLen];stream.Read(buffer, 0, buffer.Length);// 转化为字符串RequestBody = System.Text.Encoding.UTF8.GetString(buffer);}ActionArguments = Newtonsoft.Json.JsonConvert.SerializeObject(context.ActionArguments);Stopwatch = new Stopwatch();Stopwatch.Start();}/// <summary>////// </summary>/// <param name="context"></param>public override void OnActionExecuted(ActionExecutedContext context){base.OnActionExecuted(context);Stopwatch.Stop();string url = context.HttpContext.Request.Host + context.HttpContext.Request.Path + context.HttpContext.Request.QueryString;string method = context.HttpContext.Request.Method;string controller = context.Controller.ToString();string action = context.ActionDescriptor.DisplayName;string token = "";if (context.HttpContext.Request != null && context.HttpContext.Request.Headers != null && context.HttpContext.Request.Headers["Authorization"].Count > 0){token = context.HttpContext.Request.Headers["Authorization"];}string qs = ActionArguments;dynamic result = context?.Result?.GetType()?.Name == "EmptyResult" ? new { Value = "无返回结果" } : context?.Result as dynamic;string res = "在返回结果前发生了异常";try{if (result != null){res = Newtonsoft.Json.JsonConvert.SerializeObject(result.Value);}}catch (System.Exception){res = "日志未获取到结果，返回的数据无法序列化";}NLogger.Info($"地址：{url} \n " +$"controller：{controller} \n " +$"action：{action} \n " +$"token：{token} \n " +$"方式：{method} \n " +$"请求体：{RequestBody} \n " +$"参数：{qs}\n " +$"结果：{res}\n " +$"耗时：{Stopwatch.Elapsed.TotalMilliseconds} 毫秒（指控制器内对应方法执行完毕的时间）");}}
}