Online library General info:

• Application is managing customers and books that can be bought by a customer. Each customer has a list of purchased books.
• The application is written with Java 11 and Spring Boot.
• Customers and books are persisted in memory in static collections for simplicity. There is no real database or in memory database used.
• Collections that were used to persist entities are not thread safe for simplicity.
• The application does not contain any logging functionality for simplicity.
• The application has no units tests.
• Integration tests are testing Customer Controller and covers the controller/service/repository layers.
• Validations were performed with Hibernate Validator.
• The mapping between DTO's and entities is done via ModelMapper.class.
• Custom exceptions are handled by using a ControllerAdvice.
• The application does not have Swagger for API Documentation for simplicity.

RUNNING THE APPLICATION:

• USING IDE: Run the main class OnlineLibraryApplication

• USING MAVEN: Run from the root directory mvn spring-boot:run

• Being a Spring boot application, when starting the Online Library, an embedded application server will start on port 8080 (Tomcat)

• The application will be reachable at http://localhost:8080/

Endpoints:

Customer endpoints:

• POST /customers creates a customer
• PUT /customers/{id} updates an existing customer
• DELETE /customers/{id} deletes an existing customer
• GET /customers retrieves all customers
• GET /customers/{id} retrieves the customer with the specified path id

Books endpoints: -IMPORTANT NOTE: Book endpoints can be used only if the requests contain a valid tokenin the headers that is obtained by using the login API

• POST /books creates a book
• PUT /books/{id} updates an existing book
• DELETE /books/{id} deletes an existing book
• GET /books retrieves all books
• GET /books/{id} retrieves the book with the specified path id
• POST /books/{id}/buy?customerId={} accepts the customer and the book id that should be bought by the customer - customer id is passed as a query parameter

Login

• POST /login accepts the email and password of a customer and generates a token that will be valid for 24 hours

• After a token is generated, it is saved in memory. Each token tracks the generation date in order to perform the 24 hours validation.

• Requests are intercepted by a custom interceptor which is expecting a valid token in the request headers.