How to handle errors in middleware C# Asp.net Core?
https://www.tutorialspoint.com/how-to-handle-errors-in-middleware-chash-asp-net-core
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03-10-2020 - |
Question
How to handle errors in middleware C# Asp.net Core?
Create a new folder named CustomExceptionMiddleware and a class ExceptionMiddleware.cs inside it.
The first thing we need to do is to register our IloggerManager service and RequestDelegate through the dependency injection.
The _next parameter of RequestDeleagate type is a function delegate that can process our HTTP requests.
After the registration process, we need to create the InvokeAsync() method. RequestDelegate can’t process requests without it.
The _next delegate should process the request and the Get action from our controller should generate a successful response. But if a request is unsuccessful (and it is, because we are forcing exception),
our middleware will trigger the catch block and call the HandleExceptionAsync method.
public class ExceptionMiddleware{ private readonly RequestDelegate _next; private readonly ILoggerManager _logger; public ExceptionMiddleware(RequestDelegate next, ILoggerManager logger){ _logger = logger; _next = next; } public async Task InvokeAsync(HttpContext httpContext){ try{ await _next(httpContext); } catch (Exception ex){ _logger.LogError($"Something went wrong: {ex}"); await HandleExceptionAsync(httpContext, ex); } } private Task HandleExceptionAsync(HttpContext context, Exception exception){ context.Response.ContentType = "application/json"; context.Response.StatusCode = (int)HttpStatusCode.InternalServerError; return context.Response.WriteAsync(new ErrorDetails(){ StatusCode = context.Response.StatusCode, Message = "Internal Server Error from the custom middleware." }.ToString()); } }
Modify our ExceptionMiddlewareExtensions class with another static method −
public static void ConfigureCustomExceptionMiddleware(this IApplicationBuilder app){ app.UseMiddleware<ExceptionMiddleware>(); }
use this method in the Configure method in the Startup class −
app.ConfigureCustomExceptionMiddleware();