ErrorHandlingMiddleware

ErrorHandlingMiddleware.cs

public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate _next;
    private readonly EmailSettings _settings;

    public ErrorHandlingMiddleware(RequestDelegate next, IOptions<EmailSettings> settings)
    {
        _next = next;
        _settings = settings.Value;
    }

    public async Task Invoke(HttpContext context)
    {
        // This will catch all exceptions if not caught anywhere else
        try
        {
            await _next(context);
        }
        catch (SqlException ex)
        {
            EmailService.SendSqlException(ex, context.User.Identity.Name, _settings);
            await HandleSqlExceptionAsync(context, ex);
        }
        catch (Exception ex)
        {
            EmailService.SendException(ex, context.User.Identity.Name, _settings);
            await HandleExceptionAsync(context, ex);
        }
    }

    private static Task HandleExceptionAsync(HttpContext context, Exception ex)
    {
        var result = JsonConvert.SerializeObject(new
        {
            Type = "General Exception",
            Exception = new
            {
                Message = ex.Message,
                Inner = ex.InnerException
            }
        });

        context.Response.ContentType = "application/json";
        context.Response.StatusCode = 500;
        return context.Response.WriteAsync(result);
    }

    private static Task HandleSqlExceptionAsync(HttpContext context, SqlException ex)
    {
        var errorList = new List<Object>();

        for (int i = 0; i < ex.Errors.Count; i++)
        {
            errorList.Add(new
            {
                Message = ex.Errors[i].Message,
                Procedure = ex.Errors[i].Procedure,
                LineNumber = ex.Errors[i].LineNumber,
                Source = ex.Errors[i].Source,
                Server = ex.Errors[i].Server
            });
        }

        var result = JsonConvert.SerializeObject(new
        {
            Type = "SQL Exception",
            Exceptions = errorList
        });

        context.Response.ContentType = "application/json";
        context.Response.StatusCode = 500;
        return context.Response.WriteAsync(result);
    }
}

public static class ErrorHandlingMiddlewareExtensions
{
    public static IApplicationBuilder UseErrorHandlingMiddleware(this IApplicationBuilder builder)
    {
        return builder.UseMiddleware<ErrorHandlingMiddleware>();
    }
}