Global Exception Handling in ASP.NET Core Using Middleware and Serilog

I will reuse some parts from this article — Comprehensive Guide to Logging in ASP.NET Core with Serilog.

We will use the logging implemented in that article.

First approach

Of course, we can do it this way, but it will become tedious to write a try-catch block in every controller just to handle a Something went wrong error.

We can make this more general to avoid repetitive code by leveraging middleware.

public IActionResult GetAll()
{
    try
    {
        logger.LogInformation("Started fetching todos");
    
        var todos = new List<Todo>
        {
            new()
            {
                Id = Guid.NewGuid(),
                Title = "Walk a dog",
            }
        };
    
        logger.LogInformation("Finished fetching todos");
        return Ok(todos);
    }
    catch (Exception ex)
    {
        return Problem("Something went wrong.", null, (int)HttpStatusCode.InternalServerError);
    }
}

Middleware

We will wrap the next delegate in a try-catch block. This is commonly how middleware works: if everything is fine within the middleware, simply call next to proceed to the next part of the pipeline.

If something goes wrong, we handle it in the catch block. In this block, we log the error, prepare a JSON response, and return it to the client.

In the root of the project, create a folder named Middleware with an ExceptionHandlerMiddleware.cs file.

using System.Net;

namespace MediumLogging.Middlewares;

public class ExceptionHandlerMiddleware(ILogger<ExceptionHandlerMiddleware> logger, RequestDelegate next)
{
    public async Task InvokeAsync(HttpContext httpContext)
    {
        try
        {
            await next(httpContext);
        }
        catch (Exception ex)
        {
            var errorId = Guid.NewGuid();
            
            logger.LogError(ex, $"{errorId}: {ex.Message}");
            
            httpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            httpContext.Response.ContentType = "application/json";

            var error = new
            {
                Id = errorId…