The idea here is to design a web solution following the SOLID design principles. There are five principles:

• Single Responsibility Principle (SRP) - A class should have single reponsibility.

• Open Closed Principle (OCP) - Should be open for extension but closse for modification.

• Liskov Substitution Principle (LSP) - Base class instance should be replacable by its sub class instance.

• Interface Segregation Principle (ISP) - Multiple useful interfaces.

• Dependency Inversion Principle (DIP) - High level modules should not depend on low level module, both should depend on abstractions.

Technology stack: C#, .Net Framework 4.6, Rest API, WCF, Ninject, MSSQL, etc.

There are 8 projects in this solution.

API

• The contract.
• ServiceFactory to determine which service end points (WCF, WCFIIS, DEV) to listen to via http or tcp protocol.

SRC

• Default implementation of the API contract.
• UnitOfWork, Databases, Repositories, Logics, Mappers, etc.
• Depends on API.

SRC.TEST

• Unit test, integration test.
• Depends on API, SRC.

WCF

• Host a WCF service to expose SRC via http or tcp protocol.
• Depends on API, SRC.
• Make sure to run this locally with Admin privilege.

WCFISS

• IIS hosted WCF service. (At the moment it is not exposing SRC). Only some dummy implementation of the API contract.
• Depends on API.
• Make sure to run this locally with Admin privilege.

DEV

• This is the developers page. It has a reference to SRC and route all api requests internally to SRC.
• Depends on API, SRC.

RESTAPI

• This is the restful API implementation project. It can listen to WCF / WCFIIS / DEV.
• Locally it is listening to WCF(http) project.
• Depends on API.

WEB

• This is the public website. It can listen to WCF / WCFISS/ DEV.
• Locally it is listening to DEV project.
• Depends on API.

• Create two databases "HelloWorld" and "LoremIpsum". Create tables Cats, Dogs for the "HelloWorld" database and create table Tigers for LoremIpsum database. Each table has only two columns (i.e., CatId, Color). Populate some default data.
• Make sure to update the connection strings in WCF (App.config), DEV (Web.config), SRC.TEST (app.config) with your local database host address.