Transcript
Fat ControllerCQRS Diet
Derek Comartin@codeopinion
codeopinion.com
Context
WinForm PHP
LOBApplications
WinForm ASP.NET MVC
LOBApplications
Authorization
Authorization
Data Access
Authorization
Data Access
Validation
Authorization
Data Access
Validation
Business Logic
Authorization
Data Access
Validation
Business Logic
Too Many Mixed Responsibilities(aka Turd Pile)
MVCDatabase
Auth DALBLL
Layer All The Things(aka Layered Turd Pile)
MVC
DatabaseAuth DALBLL
WinForm
Layer All The Things(aka Layered Turd Pile)
Minimize Coupling to a Framework
Applications are not 1:1Simple Changes
2 Major Pain PointsLayered
DAL/ProductModel.csDAL/ProductRepository.csBLL/ProductManager.csMVC/ProductController.cs
Simple ChangesLayered
CQRS is simply the creation of two objects where there was previously only one. The separation occurs based upon whether the methods are a command or a query (the same definition that is used by Meyer in Command and Query Separation, a command is any method that mutates state and a query is any method that returns a value).
– Greg Young
CQRS
http://www.codeproject.com/Articles/555855/Introduction-to-CQRS
Not this…
MVCDatabase
Auth DALBLL
Layered
Controller
Command
Query
Database
CQRS
Controller
Command
QueryDatabase
BLL
DAL
DAL
Auth
Auth
CQRS
Define an object that encapsulates how a set of
objects interact
Mediator Pattern
Object BObject A
Mediator Pattern
Mediator Object BMessage MessageObject A
Mediator Pattern
MediatR
https://github.com/jbogard/MediatR
Query = Message = Request
Mediator Pattern
MediatR Query HandlerQuery
MediatR
MediatR Query HandlerQuery
MediatR Query
MediatR Query
MediatRQuery Query Handler
MediatR Query Handler
Command = Message = Request
MediatR Command
Notification Handler
Notification Handler
Notification Handler
Notification
MediatR Notification
MediatR
Notification Handler
Notification
MVCControllersModelsViewsViewModels
Organize By Layer
Controllers/ShoppingCartController.csViewModels/ShoppingCartViewModel.csModels/ShoppingCart.csViews/ShopingCart/Index.cshtml
Organize By Layer
FeaturesShoppingCart
AddToCart.csRemoveFromCart.cs
ViewCart.csViewCart.cshtml
ModelsShoppingCart.csAlbum.csCartItem.cs
Organize By Feature
ASP.NET MVC
Feature Feature Feature Feature Feature
Database
Data Model
Organize By Feature
Move from ASP.NET WebAPI to Nancy
1 file per Command/Query (incl. Controller)
Shared concerns can be changed per feature (EF vs EF Core vs Dapper)
Success!
Segregate our code from Framework
MediatR between integration boundaries
Feature Slices not Layers
Success!
Compile Time Type CheckingTestsAnalyzer
Container & RegistrationsTests
Trade-Offs & Notes
That’s it…Thanks!
Derek Comartin@codeopinion
codeopinion.com
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