第37章 抽离跨域异常处理管道中间件之CorsExceptionHandlerMiddleware

public class CorsExceptionHandlerMiddleware
{
    private readonly RequestDelegate _next;
 
    public CorsExceptionHandlerMiddleware(RequestDelegate next)
    {
        _next = next;
    }
 
    public async Task Invoke(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (Exception ex)
        {
            // 处理异常，设置响应状态码和内容
            context.Response.StatusCode = StatusCodes.Status500InternalServerError;
            context.Response.ContentType = "application/problem+json";
            var problemDetails = new ProblemDetails
            {
                Status = StatusCodes.Status500InternalServerError,
                Title = "An error occurred while processing your request.",
                Detail = ex.Message,
                Instance = context.Request.Path.Value
            };
            await context.Response.WriteAsync(JsonConvert.SerializeObject(problemDetails));
        }
    }
}
 
// 在Startup.cs中配置CorsExceptionHandlerMiddleware
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // ...
 
    // 添加CORS异常处理中间件
    app.UseMiddleware<CorsExceptionHandlerMiddleware>();
 
    // ...
}

这个代码实例展示了如何创建一个自定义的CORS异常处理中间件，并在Startup.cs中配置它。当下游中间件链中的中间件抛出异常时，这个自定义中间件会捕获异常，设置合适的HTTP状态码和响应内容，这有助于提高API服务的可靠性和安全性。