自定义404响应模型

Question

我想为我们的API上的所有404提供自定义响应.例如:

{
  "message": "The requested resource does not exist. Please visit our documentation.."
}

我相信以下结果过滤器适用于MVC管道中的所有情况:

public class NotFoundResultFilter : ResultFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext context)
    {
        var result = context.Result as NotFoundResult;

        if (result != null)
        {
            context.Result = new HttpNotFoundResult(); // My custom 404 result object
        }
    }
}

但是,当请求的URL与操作路由不匹配时,不会触发上面的过滤器.我怎样才能最好地拦截这404条回复？ 这需要中间件吗？

Answer 1

是的,您需要使用中间件,因为过滤器仅适用于MVC.

1. 您可以像往常一样编写自己的中间件

   app.Use(async (context, next) =>
   {
       await next();
       if (context.Response.StatusCode == 404)
       {
           context.Response.ContentType = "application/json";
   
           await context.Response.WriteAsync(JsonConvert.SerializeObject("your text"), Encoding.UTF8);
       }
   });
   

2. 或者使用内置的middlware StatusCodePagesMiddleware,但由于您只想处理一个状态,这是一个额外的功能.此中间件可用于处理响应状态代码在400到600之间.您可以配置StatusCodePagesMiddleware,将以下行之一添加到Configure方法中(例如来自StatusCodePages Sample):

   app.UseStatusCodePages(); // There is a default response but any of the following can be used to change the behavior.
   
   // app.UseStatusCodePages(context => context.HttpContext.Response.SendAsync("Handler, status code: " + context.HttpContext.Response.StatusCode, "text/plain"));
   // app.UseStatusCodePages("text/plain", "Response, status code: {0}");
   // app.UseStatusCodePagesWithRedirects("~/errors/{0}"); // PathBase relative
   // app.UseStatusCodePagesWithRedirects("/base/errors/{0}"); // Absolute
   // app.UseStatusCodePages(builder => builder.UseWelcomePage());
   // app.UseStatusCodePagesWithReExecute("/errors/{0}");