264 Exception Handling Middleware

示例

CRUDExample项目新建Middlewares文件夹，下面新建ExceptionHandlingMiddleware.cs（VS中有Middleware模板）

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Serilog;
using System.Threading.Tasks;

namespace CRUDExample.Middlewares
{
    // You may need to install the Microsoft.AspNetCore.Http.Abstractions package into your project
    public class ExceptionHandlingMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger<ExceptionHandlingMiddleware> _logger;  
        private readonly IDiagnosticContext _diagnosticContext;

        public ExceptionHandlingMiddleware(RequestDelegate next, ILogger<ExceptionHandlingMiddleware> logger, IDiagnosticContext diagnosticContext)
        {
            _next = next; //represents the subsequent middleware
            _logger = logger;
            _diagnosticContext = diagnosticContext;
        }

        public async Task Invoke(HttpContext httpContext)
        {
            try
            {
                await _next(httpContext);  
            }
            catch (Exception ex)
            {
                if (ex.InnerException != null)
                {
                    _logger.LogError("{ExceptionType}{ExceptionMassage}", ex.InnerException.GetType().ToString(), ex.InnerException.Message);
                }
                else
                {
                    _logger.LogError("{ExceptionType}{ExceptionMassage}", ex.GetType().ToString(), ex.Message);
                }
            }
            httpContext.Response.StatusCode = 500;
            await httpContext.Response.WriteAsync("Error occurred");
        }
    }

    // Extension method used to add the middleware to the HTTP request pipeline.
    public static class ExceptionHandlingMiddlewareExtensions
    {
        public static IApplicationBuilder UseExceptionHandlingMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<ExceptionHandlingMiddleware>();
        }
    }
}

Program.cs

var app = builder.Build();

app.UseSerilogRequestLogging();

if (builder.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}
else
{
    app.UseExceptionHandlingMiddleware();
}

注意

对于测试环境，按照上面的代码，如果有错误会显示详细的错误信息到页面；

对于生产环境，如果不使用自定义中间件抓取报错信息，页面会显示类似400、500等报错，使用自定义中间件后可以在页面展示自定义的容易理解的报错信息，比如“Error occurred”。

launchSettings.json中可以设置运行环境：

"environmentVariables": {
  "ASPNETCORE_ENVIRONMENT": "Production"
}

Gitee获取源码：

https://gitee.com/huang_jianhua0101/asp.-net-core-8.git