Single Web API controller per resource or less controllers with more custom actions?

Question

I want to expose most of my business layer methods to a Web API project to allow for broader consumption.

One idea is to have one Web API controller per resource.

Answer 1

This boils down to a simple design principle - separation of concerns (SoC), you should have a think about what functionality from your business layer you want to expose and create controllers based on that.

From your example above, you might create a ProductController and CustomerController, which could expose the following endpoints:

GET /api/customer/1234        # gets customer by id
POST /api/customer/create     # creates a new customer
GET /api/customer/1234/items  # gets all items for a customer
GET /api/product/9876         # gets a product by id
POST /api/product/create      # creates a new product

Hope that helps...