c# - ExceptionHandling : If controller method returns json then return json, if View then return Redirect

Question

我想实现这样的目标:

如果在返回 Json 的方法中抛出异常，则返回 new Json(new { success = false, error = "unknown"});

但如果方法返回 View 则返回 Redirect

public async Task Invoke(HttpContext ctx)
{
    try
    {
        await next(ctx);
    }
    catch (Exception ex)
    {
        HandleException(ctx, ex);
    }
}

private static void HandleException(HttpContext context, Exception ex)
{
    // some logger
    LoggerService.Log(ex);

    context.Response.Redirect("/Error/ErrorPage");
}

如何确定请求发送到哪里？我的意思是如何获取请求发送到的方法类型？

因为我想做一些类似typeof(targetMethod) 的事情来确定它是否是例如JsonResult

Answer 1

听起来您正在尝试处理 Action 方法抛出的异常。如果是这样的话，ASP.NET Core 有一个内置的 IExceptionFilter , 这适用于:

A filter that runs after an action has thrown an Exception.

为了实现您的目标，创建一个CustomExceptionFilter:

public class CustomExceptionFilter : IExceptionFilter
{
    private ILogger<CustomExceptionFilter> _logger;

    public CustomExceptionFilter(ILogger<CustomExceptionFilter> logger)
    {
        this._logger = logger;
    }

    public void OnException(ExceptionContext context)
    {
        var ex = context.Exception;
        var c = (ControllerActionDescriptor) context.ActionDescriptor;

        if(c == null){
            context.Result = new StatusCodeResult(500);
        } else if (typeof(JsonResult) == c.MethodInfo.ReturnType) {
            context.Result = new JsonResult(new { success = false, error = "unknown" });
        } else {
            // Redirect
            this._logger.LogCritical(ex,ex.Message);
            context.Result = new RedirectResult("/Error/ErrorPage");
        }
    }
}

并如下注册这个过滤器:

services.AddMvc(opts => {
    opts.Filters.Add(typeof(CustomExceptionFilter));
});

它对我来说很好。