CQRS, API Development, and Module Communication

CQRS, API Development, and Module Communication

This course is part of .NET 8 Backend Bootcamp – Modulith, DDD & CQRS Specialization

Instructor: Packt - Course Instructors

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10 modules

Gain insight into a topic and learn the fundamentals.

Intermediate level

Recommended experience

15 hours to complete

3 weeks at 5 hours a week

Flexible schedule

Learn at your own pace

Earn a Certificate

With paid plans

10 modules

Gain insight into a topic and learn the fundamentals.

Intermediate level

Recommended experience

15 hours to complete

3 weeks at 5 hours a week

Flexible schedule

Learn at your own pace

Earn a Certificate

With paid plans

What you'll learn

Implement CQRS and MediatR to efficiently manage commands and queries in modular applications.
Develop modular APIs using minimal APIs, Carter, and REPR design patterns for efficient communication
Handle cross-cutting concerns like validation, logging, and exception handling within the MediatR pipeline
Optimize application performance with distributed caching strategies using Redis in modular systems

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This course is part of the .NET 8 Backend Bootcamp – Modulith, DDD & CQRS Specialization

When you enroll in this course, you'll also be enrolled in this Specialization.

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There are 10 modules in this course

This course covers the implementation of CQRS (Command Query Responsibility Segregation) patterns and API development using MediatR for modular communication in .NET-based applications. You’ll learn how to structure applications using CQRS, focusing on the separation of read and write operations, and explore the integration of MediatR for handling commands and queries. With real-world examples, you will see how these patterns improve scalability and modularity in your applications.

The journey begins with an introduction to CQRS and its role in managing complex systems by segregating commands and queries. You will learn how to implement CQRS logically and physically in your applications, utilizing MediatR to manage requests effectively. The course continues by exploring the development of catalog and basket modules, applying CQRS principles in real use cases, and handling domain events with MediatR’s INotificationHandler interface. As you progress, you will build REST APIs for catalog and basket modules using minimal APIs, Carter, and the REPR design pattern. You will also dive into handling cross-cutting concerns like validation, logging, and error handling, integrating them into your MediatR pipeline. Additionally, the course addresses caching strategies with Redis, providing a hands-on approach to optimizing performance in distributed systems. This course is designed for developers interested in building scalable, maintainable systems using modular monoliths with CQRS, MediatR, and minimal APIs. It is ideal for those looking to enhance their understanding of modular architecture and API development using .NET 8.

In this module, we will dive into developing application use cases with CQRS and MediatR. You will learn how to structure commands and queries separately to streamline processing, implement MediatR for command and query handling, and create abstractions that enhance modularity and clarity in your workflows.

What's included

7 videos2 readings1 assignment

7 videosTotal 29 minutes

Introduction - Application Use Case Development with CQRS and MediatR1 minutePreview module
CQRS (Command Query Responsibility Segregation) Pattern3 minutes
Logical and Physical Implementation of CQRS Pattern2 minutes
CQRS Design Pattern With MediatR Library (Logical CQRS Implementation)4 minutes
Develop Feature Handler Class with CQRS and MediatR9 minutes
Create Abstraction on MediatR for CQRS - Command and Query Separation4 minutes
Create Abstraction on MediatR for CQRS - Command and Query Separation - Part 24 minutes

2 readingsTotal 20 minutes

Introduction to the course "CQRS, API Development, and Module Communication"10 minutes
Full Course Resources Specialization10 minutes

1 assignmentTotal 15 minutes

Application Use Case Development with CQRS and MediatR - Assessment15 minutes

In this module, we will explore how to apply CQRS and MediatR for developing catalog module use cases. You will learn how to create and organize CQRS components, including handling commands and queries for product data, and using MediatR for efficient request processing in the catalog module.

What's included

15 videos1 assignment

15 videosTotal 58 minutes

Introduction - Catalog Application Use Case Development with CQRS and MediatR1 minutePreview module
Quick Remember Catalog Module Application Use Cases Analysis1 minute
Develop Catalog Module Folder Structure for CQRS2 minutes
Develop DTO Classes for Product in Catalog Module1 minute
Develop Products CreateProductCommand and Handler in Catalog Modules Application5 minutes
Develop Products CreateProductCommandHandler using CatalogDbContext in Catalog3 minutes
Develop Products UpdateProductCommand and Handler using CatalogDbContext6 minutes
Develop Products DeleteProductCommand and Handler using CatalogDbContext3 minutes
Develop Product Queries with CQRS and MediatR in Catalog Module5 minutes
Mapping with Mapster3 minutes
Develop Product Queries with CQRS and MediatR in Catalog Module with Mapster2 minutes
Develop GetProductByCategory Queries with CQRS and MediatR in Catalog Module3 minutes
Develop GetProductById Queries with CQRS and MediatR in Catalog Module5 minutes
Develop Domain Event Handlers with MediatR INotificationHandler in Catalog5 minutes
Develop Domain Event Handlers with MediatR INotificationHandler - Part 25 minutes

1 assignmentTotal 15 minutes

Catalog Application Use Case Development with CQRS and MediatR - Assessment15 minutes

In this module, we will focus on building lightweight and efficient catalog API endpoints using minimal APIs with Carter. You will learn how to expose essential product operations through RESTful APIs while adhering to CQRS patterns and utilizing the REPR design pattern for optimized request handling.

What's included

18 videos1 assignment

18 videosTotal 96 minutes

Introduction - Develop Catalog API Endpoints Exposing Minimal API Endpoints1 minutePreview module
REPR Design Pattern and CQRS MediatR Request Lifecycle1 minute
Minimal APIs and Install Carter Library to Expose Minimal APIs4 minutes
Quick Remember Catalog Module Endpoints Analysis2 minutes
Develop CreateProduct POST Endpoint with Carter Implements ICarterModule5 minutes
Develop CreateProduct POST Endpoint with Carter Implements ICarterModule - Part 25 minutes
Developing UpdateProduct Endpoint for REST APIs in Catalog Module5 minutes
Developing DeleteProduct Endpoint for REST APIs in Catalog Module4 minutes
Developing GetProducts Endpoint for REST APIs in Catalog Module4 minutes
Developing GetProductById Endpoint for REST APIs in Catalog Module4 minutes
Developing GetProductByCategory Endpoint for REST APIs in Catalog Module4 minutes
Register Carter Libraries into ASP.NET Dependency Injection Service and Request6 minutes
Create Extension Method for Carter Assembly Registrations6 minutes
Create Postman Collection for EShopModules6 minutes
Test Catalog Module - CreateProduct POST Request - Debug Carter Minimal API10 minutes
Test UpdateProduct Endpoint with CQRS and VSA in Catalog Module8 minutes
Test Get Product Endpoints with CQRS and VSA in Catalog Module9 minutes
Test DeleteProduct Endpoint with CQRS and VSA in Catalog Module4 minutes

1 assignmentTotal 15 minutes

Develop Catalog API Endpoints Expose Minimal API Endpoints with Carter and REPR - Assessment15 minutes

In this module, we will explore how to manage cross-cutting concerns such as validation, exception handling, and logging in modular applications. You will learn to integrate Fluent Validation, automate validation in MediatR pipelines, and implement structured logging and global exception handling to enhance the application's reliability and maintainability.

What's included

18 videos1 assignment

18 videosTotal 113 minutes

Introduction - Develop Cross-cutting Concerns for Catalog and Each Module1 minutePreview module
MediatR Pipeline Behaviors and Fluent Validation Library4 minutes
Add Cross-cutting Concerns into Shared Class Library to Use in All Modules2 minutes
Apply Validation with AbstractValidator using Fluent Validation Library4 minutes
Apply Validation with AbstractValidator using Fluent Validation Library - Part 27 minutes
Validation Pipeline Behavior with MediatR using Fluent Validation Library8 minutes
Remove Manual Validator and Test Validation Pipeline Behavior with MediatR4 minutes
Develop CRUD Command Validators with Fluent Validation4 minutes
Global Handling Exceptions in ASP.NET Core with app.UseExceptionHandler5 minutes
Shared Handle Exceptions Generic Way in ASP.NET Core with app.UseExceptionHandler10 minutes
Global Exception Handling with IExceptionHandler Interface in ASP.NET Core8 minutes
Register Custom Exception Handling into ASP.NET with AddExceptionHandler Method8 minutes
Logging Behavior in MediatR Pipeline for Cross-cutting Concerns7 minutes
Test Logging Behavior for All MediatR Requests on Catalog Module6 minutes
Structured Logging Using Serilog in .NET 8.0 Minimal APIs9 minutes
Serilog WriteTo Seq for Structured Logging in .NET7 minutes
Develop Pagination Class for Query GetProducts using CQRS and MediatR3 minutes
Develop GetProducts Query Apply Pagination using CQRS and MediatR9 minutes

1 assignmentTotal 15 minutes

Develop Cross-cutting Concerns for Catalog and Each Module in EShop Modules - Assessment15 minutes

In this module, we will focus on developing the basket module using vertical slice architecture and CQRS. You will learn how to design domain models for the shopping cart, structure commands and queries efficiently, and implement CQRS patterns for handling operations related to the basket module.

What's included

5 videos1 assignment

5 videosTotal 19 minutes

Introduction - Develop Basket Module with Vertical Slice Architecture and CQRS1 minutePreview module
Domain Analysis of Basket Module: Models, UCs, Rest APIs, Databases4 minutes
Technical Analysis of Basket Module: Architectures, Patterns, Libraries, Folders2 minutes
Develop ShoppingCart Domain Entity Models in Basket Domain Entities5 minutes
Develop DDD Rich-domain Model Entity for ShoppingCart Entities5 minutes

1 assignmentTotal 15 minutes

Develop Basket Module with Vertical Slice Architecture and CQRS - Assessment15 minutes

In this module, we will explore the process of setting up EF Core with PostgreSQL for the basket module. You will learn how to apply the code-first approach to create the database schema, implement migrations, and configure EF Core mappings to persist domain models into PostgreSQL efficiently.

What's included

13 videos1 assignment

13 videosTotal 46 minutes

Introduction - Develop Basket Data-Infrastructure with EF Core Code First2 minutesPreview module
Steps of Infrastructure EF Core Developments for Basket Module3 minutes
Develop EF Core DbContext Object for Storing Entities in Basket Infrastructure6 minutes
Mapping DDD Objects to EF Entities - Develop EF Core Entity Configurations4 minutes
EF Core 8 Relations and DDD ValueObject Mapping with ComplexType and Property2 minutes
Develop SC and SC Items Relations Entity Configurations1 minute
EF Core SQL Server Connection String in appsettings.json file1 minute
Register EF Core DbContext in ASP.NET Dependency Injection Tool for PostgreSQL4 minutes
Create EF Core Migrations for BasketDbContext in Basket Infrastructure5 minutes
Run Docker-Compose on Visual Studio to Setup PostgreSQL on Docker2 minutes
Apply EF Core Migrations to PostgreSQL DB with Update-Database Command3 minutes
Auto Migrate EF Core Entities to PostgreSQL When Application Startup with Coding3 minutes
Test Auto-Migrations with UseMigration Extension Method on WebApplication4 minutes

1 assignmentTotal 15 minutes

Develop Basket Data-Infrastructure with EF Core Code First and PostgreSQL - Assessment15 minutes

In this module, we will focus on developing use cases for the basket module using CQRS and MediatR. You will learn how to implement commands and queries for basket operations, structure the folder architecture for better organization, and leverage MediatR to handle requests effectively within the application.

What's included

9 videos1 assignment

9 videosTotal 39 minutes

Introduction - Basket Application Use Case Development with CQRS and MediatR1 minutePreview module
Develop Basket Folder Structure for CQRS3 minutes
Develop DTO Classes for ShoppingCart in Basket Module2 minutes
Develop Basket CreateBasketCommand and Handler in Basket Application Use Cases5 minutes
Develop Basket CreateBasketCommandHandler using BasketDbContext in Basket Module4 minutes
Develop Basket DeleteBasketCommand and Handler using BasketDbContext in Basket7 minutes
Develop Basket Queries with CQRS and MediatR in Basket Module4 minutes
Develop Basket AddItemIntoBasketHandler with CQRS and MediatR5 minutes
Develop Basket RemoveItemFromBasketHandler with CQRS and MediatR4 minutes

1 assignmentTotal 15 minutes

Develop Basket Application Use Case Development with CQRS and MediatR - Assessment15 minutes

In this module, we will develop minimal API endpoints for the basket module using Carter. You will learn how to expose essential basket operations through RESTful APIs, integrate CQRS and VSA patterns, and optimize API request processing for better performance and scalability.

What's included

14 videos1 assignment

14 videosTotal 73 minutes

Introduction - Develop Basket API Endpoints Exposing Minimal API Endpoints2 minutesPreview module
Develop CreateBasket POST Endpoint with Carter Implements ICarterModule8 minutes
Develop DeleteBasket Endpoint with Carter Implements ICarterModule3 minutes
Develop GetBasket Endpoint with Carter Implements ICarterModule for Minimal APIs4 minutes
Develop AddItemIntoBasket Endpoint with Carter Implements ICarterModule7 minutes
Develop RemoveItemFromBasket Endpoint with Carter Implements ICarterModule5 minutes
Register MediatR and Carter Libraries into ASP.NET Dependency Injection Service6 minutes
Register MediatR Libraries into ASP.NET Dependency Injection Service and Request6 minutes
Develop MediatR Extension Method for Custom Registration With Assemblies3 minutes
Test Basket API - CreateBasket POST Request - Debug Carter Minimal API6 minutes
Test Get Basket Endpoints with CQRS and VSA in Basket Module3 minutes
Test DeleteBasket Endpoint with CQRS and VSA in Basket Module2 minutes
Test AddItemIntoBasket Endpoint with CQRS and VSA in Basket Module8 minutes
Test RemoveItemFromBasket Endpoint with CQRS and VSA in Basket Module4 minutes

1 assignmentTotal 15 minutes

Develop Basket API Endpoints Exposing Minimal API Endpoints with Carter and REPR - Assessment15 minutes

In this module, we will explore how to implement Redis as a distributed cache in the basket module. You will learn how to optimize data retrieval using the cache-aside pattern, configure Redis within the application, and manage cache invalidation for better performance and consistency.

What's included

21 videos1 assignment

21 videosTotal 113 minutes

Introduction - Develop Distributed Caching with Redis in Basket Module2 minutesPreview module
Develop BasketRepository Class using EF Core DbContext Object5 minutes
Implement IBasketRepository Class using EF Core DbContext Object5 minutes
Register IBasketRepository into DI of Basket Module1 minute
Inject and Use IBasketRepository into Handler Classes in Basket Module7 minutes
Inject and Use IBasketRepository into AddItem and RemoveItem Handler Classes3 minutes
Quick Test Basket Endpoint with CQRS and VSA in Basket Module6 minutes
Cache-aside Pattern and Cache Invalidation3 minutes
Proxy Pattern, Decorator Pattern, and Scrutor Library3 minutes
Develop CachedBasketRepository with Proxy Pattern, Decorator Pattern, and Scrutor4 minutes
Develop CachedBasketRepository with Proxy Pattern, Decorator Pattern - Part 210 minutes
Develop CachedBasketRepository with Proxy Pattern, Decorator Pattern - Part 37 minutes
Register Decorated CachedBasketRepository and StackExchangeRedis with Scrutor6 minutes
Register StackExchangeRedis into Common DI in API Project Program.cs4 minutes
Setup Redis as a Distributed Cache using Docker-compose File for Multi-container4 minutes
Run Docker-Compose on Visual Studio to Setup Redis Distributed Cache on Docker3 minutes
Connect Redis Cache from Local Basket Module and Send GET Request Basket Cache8 minutes
Develop Custom JsonConverter for ShoppingCart and Items When Reading to Redis7 minutes
Develop Custom JsonConverter for ShoppingCart and Items - Part 23 minutes
Use Custom JsonSerializerOptions with JsonConverter for ShoppingCart and Items4 minutes
Quick Test Basket Endpoint with CachedBasket Repository and Custom JsonConverter10 minutes

1 assignmentTotal 15 minutes

Develop Distributed Caching with Redis in Basket Module - Assessment15 minutes

In this module, we will explore how to handle synchronous communication between modules using in-process public APIs. You will learn to set up shared contracts, implement communication patterns across modules, and test the synchronization of data between different components in your application.

What's included

13 videos1 reading2 assignments

13 videosTotal 70 minutes

Introduction - Sync Communications Between Modules with In-Process Method Calls4 minutesPreview module
How Modular Monolithic Architecture Handles Communications Between Modules2 minutes
Basket Module Synchronous Use Cases - Adding an Item to the Basket Communication2 minutes
Examine AddItemIntoBasketHandler Class: Get Product Price from Catalog Module6 minutes
Sync Communication Between Modules Using Contracts Class Libraries5 minutes
Step 1: Create Catalog.Contracts Class Library2 minutes
Step 2: Move Exposing MediatR Method Query or Commands into Catalog.Contracts6 minutes
Splitting CQRS Contract-Related Common Operations into Shared.Contracts Class Library12 minutes
Step 3: Modify Catalog Module Getting Reference from Catalog.Contracts Class Library6 minutes
Step 4: Basket Get Reference from Catalog.Contracts Class Library3 minutes
Step 6: Get Product Entity Values into AddItemIntoBasketHandler and Set Price5 minutes
Test Basket AddItemIntoBasket Sync Call to Catalog Module to Get Product Data8 minutes
Step 7: Migrating Microservices: Evolving Contracts Sync Communication3 minutes

1 readingTotal 10 minutes

Conclusion to the Course" CQRS, API Development, and Module Communication"10 minutes

2 assignmentsTotal 75 minutes

Sync Communications Between Modules with In-Process Method Calls (Public APIs) - Assessment15 minutes
Full Course Assessment60 minutes

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Packt - Course Instructors

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Frequently asked questions

Yes, you can preview the first video and view the syllabus before you enroll. You must purchase the course to access content not included in the preview.

If you decide to enroll in the course before the session start date, you will have access to all of the lecture videos and readings for the course. You’ll be able to submit assignments once the session starts.

Once you enroll and your session begins, you will have access to all videos and other resources, including reading items and the course discussion forum. You’ll be able to view and submit practice assessments, and complete required graded assignments to earn a grade and a Course Certificate.