TechBuddy.Middlewares.ExceptionHandling 1.0.2

ExceptionHandling Middleware

Description

This project represents a build-in ExceptionHandling Middleware as an extension method for IApplicationBuilder It adds middleware for managing and handling unhandled exceptions in your web api project. It is also configurable by passing options whilst initializing.

Dependencies

• As it will serve infrastructure for web apis, it requires Microsoft.AspNetCore.Http.Abstractions package
• This project has been developing in NET5

Getting Started

It can be used parameterless to handle your exceptions and returns a specific response model which includes HttpStatusCode and ExceptionMessage. ExceptionMessage will only contain simple exception message unless it is configured. In this case, the default HttpStatusCode is InternalServerError(500) whereas the default ExceptionMessage is "Internal Server Error Occured!" This extension method can easily be called in Configure method in your startup.cs file of web api projects.

app.AddTBExceptionHandlingMiddleware();

class DefaultResponseModel
{
    public HttpStatusCode HttpStatusCode { get; set; }

    public string ExceptionMessage { get; set; }
}

It can also be used with MiddlewareOptions parameters which allows you to configure your exception handling ability.

ExceptionMessage will be detailed by using exception stack trace string when IsDevelopment is true.

The parameters below will override their original value when they are set.

• DefaultHttpStatusCode
• ContentType
• DefaultMessage

When ExceptionHandlerAction is set, this action will be invoked when any exception has occured.

If you want to override the DefaultResponseModel when an exception has occured, you able to use UseResponseModelCreator method by passing your customized class derived by IResponseModelCreator interface

app.AddTBExceptionHandlingMiddleware(opt =>
{
    opt.IsDevelopment = true;
    opt.DefaultHttpStatusCode = HttpStatusCode.NotFound;
    opt.ContentType = "application/json";
    opt.DefaultMessage = "An Exception Occured";
    opt.ExceptionTypeList.Add<ArgumentNullException>();

    opt.ExceptionHandlerAction = async (httpContext, exception) => 
    {
        // When exception is handled
        var logger = httpContext.RequestServices.GetRequiredService<ILogger>();
        logger.LogError(exception, exception.Message);
    };

    // Use custom respone model
    opt.UseResponseModelCreator<CustomResponseModelCreator>();
});

An example of creating your CustomResponseModelCreator

class CustomResponseModelCreator : IResponseModelCreator
{
    public object CreateModel(ModelCreatorContext model)
    {
        return new DefaultResponseModel()
        {
            ExceptionMessage = model.ErrorMessage,
            HttpStatusCode = model.HttpStatusCode
        };
    }
}

Definition of ModelCreatorContext

public class ModelCreatorContext
{
    public string ErrorMessage { get; set; }

    public HttpStatusCode HttpStatusCode { get; set; }

    public Exception Exception { get; set; }
}