ASP.Net核心异常处理中间件

Question

我正在尝试在ASP.Net Core 3.0 Web API项目中使用中间件进行异常处理：

public class ErrorHandlingMiddleware
{
private readonly RequestDelegate next;
public ErrorHandlingMiddleware(RequestDelegate next)
{
this.next = next;
}
public async Task Invoke(HttpContext context)
{
try
{
await next(context);
}
catch (Exception ex)
{
await HandleException(context, ex);
}
}
private static Task HandleException(HttpContext context, Exception ex)
{
HttpStatusCode code = HttpStatusCode.InternalServerError; // 500 if unexpected
// Specify different custom exceptions here
if (ex is CustomException) code = HttpStatusCode.BadRequest;
string result = JsonConvert.SerializeObject(new { error = ex.Message });
context.Response.ContentType = "application/json";
context.Response.StatusCode = (int)code;
return context.Response.WriteAsync(result);
}
}

启动.cs

public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// Add controllers with a route prefix
services.AddControllers(x => { x.UseGeneralRoutePrefix($"api/v{Configuration["APIVersion"]}"); });
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v0.1", new OpenApiInfo { Title = "My API", Version = "v0.1" });
});
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseHttpsRedirection();
app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint("/swagger/v0.1/swagger.json", "My API V1");
});
app.UseMiddleware(typeof(ErrorHandlingMiddleware));
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}

控制器

[HttpPost]
public ActionResult Method()
{
if (condition)
throw new CustomException();
else
return Ok();
}

但是在控制器中抛出的异常不会由中间件处理。使用中间件的正确方式是什么？

Answer 1

看来

app.UseDeveloperExceptionPage();

正在阻止异常处理中间件捕获异常。移除它可以解决问题。

Answer 2

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseCors(ApiConstantVars.AZURE_POLICY);
app.UseCors(ApiConstantVars.CORS_POLICY_NAME);
app.UseAuthentication();
app.UseMvc();
app.Run(
async context =>
{
var handler = context.Features.Get<Microsoft.AspNetCore.Diagnostics.IExceptionHandlerFeature>();
if (handler != null && handler.Error != null)
{
var errorModel = new OperationResult
{
IsSuccess = false,
};
//Handle the JSON request to respond in its origin format
if (context.Request.ContentType.ToUpper().IndexOf("JSON") != -1)
{
context.Response.ContentType = "application/json";
context.Response.StatusCode = 400; //Set the Status Code to responde JSON Failed requests
await context.Response
.WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(new { error = "Unhandled internal error", success = false, origin = context.Request.Path }))
.ConfigureAwait(false);
}
else
{
context.Response.StatusCode = (int)System.Net.HttpStatusCode.InternalServerError;
await context.Response.WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(handler.Error.Message))
.ConfigureAwait(false);
}
}
else
{
context.Response.StatusCode = (int)System.Net.HttpStatusCode.InternalServerError;
await context.Response
.WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(new { message = "Unhandled internal error" }))
.ConfigureAwait(false);
}
});
}

Answer 3

app.UseMiddleware<ErrorHandlingMiddleware>();

我认为你应该这样使用它。将此行添加到配置方法