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。

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; }        /// 
        /// 请求体中的所有值        /// 
        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。

/// 
    ///    /// 
    [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{    /// 
    /// 拦截器    /// 
    public class LogAttribute : ActionFilterAttribute    {        private string ActionArguments { get; set; }        /// 
        /// 请求体中的所有值        /// 
        private string RequestBody { get; set; }        private Stopwatch Stopwatch { get; set; }        /// 
        ///        /// 
        ///         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();        }        /// 
        ///        /// 
        ///         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）");        }    }}