ExceptionFormatter renders exceptions in a readable way. Containing important additional information which specialized exceptions may provide.
This allows you to get detailed exception messages together with all valuable information nested exceptions may hold.
- Formats all nested- and child exception in order of relevance, Inner exceptions first, outer exception last.
- Adding important value by serializing specific metadata of specialized Exceptions.
- Provides an easy extendable way to format exceptions according to preference.
- Robust implementation with fallback if any error occurs.
- Supports layouts for generic exceptions like
FaultException<T>
Use ExceptionLayoutFormatter by adding an extension class for Exceptions.
using ExceptionLayoutFormatter;
public static class ExceptionExtensions
{
private static readonly ExceptionFormatter ExceptionFormatter;
static ExceptionExtensions()
{
ExceptionFormatter = ExceptionFormatter.Create();
}
public static string FormatException(this Exception ex)
{
return ExceptionFormatter.FormatException(ex);
}
}Custom ExceptionLayouts can be added by scanning one or more assemblies.
ExceptionFormatter.Create(typeof(OptimisticConcurrencyExceptionLayout).Assembly); ExceptionLayouts can be added explicitely
ExceptionFormatter.Create()
.AddExceptionLayout(new DbEntityValidationExceptionLayout()); Or by type
ExceptionFormatter.Create()
.AddExceptionLayout(typeof(GenericFaultExceptionLayout<>)); To implement a layout for a given exception you have to implement the IExceptionLayout<TException> interface.
public interface IExceptionLayout<in TException> : IExceptionLayout
where TException : Exception
{
string FormatException(IFormatter formatter, TException ex);
}The responsibility of an exceptionLayout is to render a string given an exception.
public interface IFormatter
{
JsonSerializerSettings SerializerSettings { get; }
void SetLayout(string layout);
string PrettyPrint<T>(T item);
string GetFormattedException(Exception ex, IEnumerable<string> additionalInfo);
string GetFormattedException(Exception ex, string additionalInfo = null);
}ExceptionLayout uses NLog style renders: The following line is used as default.
formatter.SetLayout("[${exceptionType}: ${message}]\n${dictionary}\n${additionalInfo}\n${stacktrace}");Available text renderers:
| exceptionType | exceptionTypeName |
| message | ex.Message |
| stackTrace | ex.StackTrace |
| dictionary | ex.Data |
| additionalInfo | specific information about the exception |
public class DbEntityValidationExceptionLayout : IExceptionLayout<DbEntityValidationException>
{
public string FormatException(IFormatter formatter, DbEntityValidationException ex)
{
var entityValidationMessages = ex.EntityValidationErrors
.Where(x => !x.IsValid)
.Select(x => formatter.PrettyPrint(new
{
ValidationErrors = x.ValidationErrors.Select(e => new
{
Property = $"{x.Entry.Entity.GetType().Name}.{e.PropertyName}",
Error = e.ErrorMessage
}),
Entity = x.Entry.Entity
}
));
return formatter.GetFormattedException(ex, entityValidationMessages);
}
} public class OptimisticConcurrencyExceptionLayout : IExceptionLayout<OptimisticConcurrencyException>
{
public string FormatException(IFormatter formatter, OptimisticConcurrencyException ex)
{
var entities = ex.StateEntries.Select(x => formatter.PrettyPrint(x.Entity));
return formatter.GetFormattedException(ex, entities);
}
} public class DbUpdateExceptionLayout : IExceptionLayout<DbUpdateException>
{
public string FormatException(IFormatter formatter, DbUpdateException ex)
{
var validationErrors = new List<string>();
try
{
validationErrors.AddRange(ex.Entries.Select(x => x.State == EntityState.Added
? formatter.PrettyPrint(new { Current = x.CurrentValues.ToObject() })
: formatter.PrettyPrint(new
{
Current = x.CurrentValues.ToObject(),
Original = x.OriginalValues.ToObject()
})));
}
catch (Exception e)
{
validationErrors.Add($"DbUpdateExceptionLayout: {e.Message}");
validationErrors.AddRange(ex.Entries.Select(x => formatter.PrettyPrint(x.Entity)));
}
return formatter.GetFormattedException(ex, validationErrors);
}
} public class ReflectionTypeLoadExceptionLayout : IExceptionLayout<ReflectionTypeLoadException>
{
public string FormatException(IFormatter formatter, ReflectionTypeLoadException ex)
{
var msg = $"Unable to load:\n{string.Join("\n", ex.Types.Select(x => x.Name))}\n";
return formatter.GetFormattedException(ex, msg);
}
} public class SqlExceptionLayout : IExceptionLayout<SqlException>
{
public string FormatException(IFormatter formatter, SqlException ex)
{
formatter.SetLayout("[${exceptionType}: ${message}]\n${additionalInfo}\n${stacktrace}");
return formatter.GetFormattedException(ex);
}
} public class FaultExceptionLayout : IExceptionLayout<FaultException>
{
public string FormatException(IFormatter formatter, FaultException ex)
{
var fault = formatter.PrettyPrint(new
{
Reason = ex.Reason.ToString(),
Action = ex.Action,
Code = ex.Code?.Name,
SubCode = ex.Code?.SubCode?.ToString(),
});
return formatter.GetFormattedException(ex, fault);
}
} public class GenericFaultExceptionLayout<T> : IExceptionLayout<FaultException<T>>
{
public string FormatException(IFormatter formatter, FaultException<T> ex)
{
var fault = formatter.PrettyPrint(new
{
Reason = ex.Reason.ToString(),
Action = ex.Action,
Code = ex.Code?.Name,
SubCode = ex.Code?.SubCode?.ToString(),
Detail = ex.Detail
});
return formatter.GetFormattedException(ex, fault);
}
}