private static string BuildUrl(ExceptionRoute route, HttpContext context)
{
RouteData r = context.GetRouteData();
ActionContext a = new ActionContext(context, r, new ActionDescriptor());
UrlHelper helper = new UrlHelper(a);
return(helper.Action(route.Action, route.Controller, new { area = route.Area, Url = context.Request.Path }));
}
protected virtual void LoadExceptionRoutes(Assembly assembly)
{
foreach (var method in assembly.FindMethodsWithAttribute<CatchesAttribute>())
{
ExceptionRoute route = new ExceptionRoute { Method = method };
foreach (var attr in method.GetAttributes<CatchesAttribute>())
{
route.Attributes.Add(attr);
}
ExceptionRoutes.Add(route);
}
}
public async Task Invoke(HttpContext context)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
try
{
await this._next(context).ConfigureAwait(false);
}
catch (Exception ex)
{
Type exceptionType = ex.GetType();
if (!ErrorHandlers.TryGetValue(exceptionType, out ExceptionRoute route))
{
if (!HandlersSearched)
{
HandlersSearched = true;
foreach (Type t in TypeFactory.GetAllTypes())
{
foreach (MethodInfo m in t.GetMethods())
{
if (m.GetCustomAttribute <HandleExceptionAttribute>() is HandleExceptionAttribute handler)
{
foreach (Type e in handler.ToHandle)
{
AllHandlers.TryAdd(e, m);
}
}
}
}
}
List <Type> searchTypes = new List <Type>();
Type toCheck = exceptionType;
do
{
searchTypes.Add(toCheck);
toCheck = toCheck.BaseType;
} while (toCheck != null && typeof(Exception).IsAssignableFrom(toCheck));
List <ExceptionHandler> potentialHandlers = new List <ExceptionHandler>();
foreach (Type possibleHandlerType in searchTypes)
{
if (AllHandlers.TryGetValue(possibleHandlerType, out MethodInfo m))
{
potentialHandlers.Add(new ExceptionHandler(possibleHandlerType, m));
}
}
Type mostDerivedHandler = TypeFactory.GetMostDerivedType(potentialHandlers.Select(p => p.ExceptionType).ToList(), typeof(Exception));
MethodInfo selectedHandler = potentialHandlers.FirstOrDefault(p => p.ExceptionType == mostDerivedHandler)?.Method;
if (selectedHandler is null)
{
ErrorHandlers.TryAdd(exceptionType, null);
}
else
{
string ControllerName = selectedHandler.DeclaringType.Name;
if (ControllerName.EndsWith("Controller", StringComparison.OrdinalIgnoreCase))
{
ControllerName = ControllerName.Replace("Controller", "");
}
string ActionName = selectedHandler.Name;
string AreaName = string.Empty;
if (selectedHandler.DeclaringType.GetCustomAttribute <AreaAttribute>() is AreaAttribute attribute)
{
AreaName = attribute.RouteValue;
}
route = new ExceptionRoute()
{
Action = ActionName,
Area = AreaName,
Controller = ControllerName
};
ErrorHandlers.TryAdd(exceptionType, route);
}
}
if (route is null)
{
throw;
}
else
{
context.Response.Redirect(BuildUrl(route, context));
}
}
}
