CrCore.Exceptions 10.0.42

Intro

A lightweight library for defining application errors, creating typed exceptions, and mapping external error codes into domain-specific exceptions.

This package contains only the core exception model and does not depend on ASP.NET Core.

Features

• Typed application exceptions
• Standard exception categories
• Structured application errors (CrError)
• External error mapping (ErrorMap)
• Exception factory (ExceptionFactory)
• No ASP.NET Core dependencies

Installation

dotnet add package CrCore.Exceptions

Error Model

Every application error is represented by CrError.

var error = new CrError("IdentityUserNotFound", "User was not found.");

Each error contains:

• Code — stable identifier for clients.
• Message — human-readable description.

Exception Categories

Applications should inherit from one of the predefined exception categories.

Available categories:

Example:

public sealed class UserNotFoundException : NotFoundException
{
    public UserNotFoundException(Guid userId) : base(
        [new CrError("IdentityUserNotFound", $"User '{userId}' was not found.")],
        "User was not found.")
    {
    }
}

Usage:

throw new UserNotFoundException(userId);

ErrorMap

External systems usually expose their own error codes.

For example:

user_not_found

Those codes can be mapped into application errors.

ErrorMap errorMap = builder
    .Add(new ErrorRegistration(
        "user_not_found",
        [new CrError("IdentityUserNotFound", "User was not found.")]))
    .Build();

Resolving an external error:

if (errorMap.TryGet("user_not_found", out var errors))
{
    throw new UserNotFoundException(errors);
}

This keeps external service contracts isolated from the application domain.

ExceptionFactory

ExceptionFactory creates typed exceptions from registered external error codes.

Registration:

ExceptionFactory factory = builder
    .Add(new ExceptionRegistration(
        new ErrorRegistration(
            "invalid_grant",
            [new CrError("IdentityInvalidCredentials", "Invalid username or password.")]),
        errors => new InvalidCredentialsException(errors)))
    .Build();

Usage:

throw factory.Create("invalid_grant");

The factory only creates exceptions for registered error codes.