A simple WebAPI to handle cart interaction:

• POST /api/cart - inserts a drink to the cart
• PUT /api/cart - updates a drink in the cart
• DELETE /api/cart/drink/{name} - deletes a drink with the given name from the cart
• GET /api/cart/drink/{name} - retreivves a drink with the given name from the cart
• GET /api/cart - lists all drinks in the cart in alphabetical order

I added a few more controlles to make the API more simmetrical:

• DELETE /api/cart - clears the card
• POST /api/cart/drink/{name} - inserts a drink with the given name to the cart
• PUT api/cart/drink{name} - updates a drink with the given name in the cart

I would prefer to have the cart OR the drink API only but the task requires both at the moment.

I have decided not to use any 3rd party libraries except from required by ASP.Net WebAPI itself. So the database is mocked with in-memory hashtable, but all methods made async to resemble EF. The IoC is mocked by using a custom simple controller activator with explicitely registered controllers. I would also replace method parameters checks with Conditions and model to entity mapping with AutoMapper.

The Web API uses basic authentication with 3 predifined users:

• alex:password1 (YWxleDpwYXNzd29yZDE=)
• bob:password2 (Ym9iOnBhc3N3b3JkMg==)
• charlie:password3 (Y2hhcmxpZTpwYXNzd29yZDM=)