Bookstore-SpringBoot-REST-DemoApp

Database Design

Entities/Tables - RDS:

1. CatalogItem: any product in the bookstore is a catalogItem. Fields are catalogItemId(Primary Key, Auto generated Sequence), createdAt(Date), updatedAt(Date)

2. Book: fields which map to a specific isbn(or book). Fields are catalogItemId(Primary Key, Foreign Key referencing CatalogItem), isbn(String, unique, not null), title(String, not null), author(String not null)

3. Sku: Sku stores stock and price data for a catalogItem. Fields are skuId(Primary Key, Auto generated Sequence), catalogItemId(Foreign Key referencing catalog item, not null), quantity(integer, not null, >=0), price(double, not null, >=0), createdAt(Date), updatedAt(Date)

4. Purchase: Stores data for every purchase made. Fields are purchaseId(Primary Key, Auto generated Sequence), skuId(foreign key referencing Sku), purchasedQuantity(integer, not null, >=0), purchasePrice(double, not null, >=0), createdAt(Date), updatedAt(Date)

This separation of catalog from book details and mapping of sku to catalogItem makes the design extensible if a new product is added after books (with the only change being creation of a new table for product specific details). Also, in the case where same catalog item may have different prices/availabilities, the ability to map multiple skus to a single catalog can solve the problem.

Elastic Search:

Elastic search has been incorporated which stores the aggregated data for each product (book in this case) in a separate index. The aggregated data consists of CatalogItem details and details specific to the product as well as list of Sku objects. Quantity is excluded from the Sku objects since it is a highly dynamically changing value.

Currently, this elastic search is being used to provide full text search over title and author of the book.

Code Structure

The code follows a simple controller - service - manager/repository layered architecture.

Controller Layer

The response object of all controllers follow a defined structure { "code": 201, "data": {...} }, "error": {...} } which is defined as class RestResponse<T> and associated with a corresponding builder for with-data and with-error cases.

The Controller Advice takes care of different exceptions and maps it to a corresponding response.

Service Layer

The requirements and business logic is defined in the service layer.

Manager/Repository Layer

This layer is responsible to handle and abstract out external interactions (with other APIs or database transactions) from the service layer.

Other considerations

Netflix Hystrix has been integrated as a circuit-breaker in case external APIs fail. Custom wrapper classes for logging and REST template calls have been written to minimize code changes if in case use of another library is needed for these purposes

Models

There are different models(POJOs) for the Database schema and the DTO structure which user sees. This is done to abstract out the database design from the user and also to format the end response/request as per the user's need.

REST APIs

Create Book

Adds a new book to the bookstore

curl --request POST 'localhost:9000/books' --header 'Content-Type: application/json' --data-raw '{ "book": { "isbn": "100000001", "title": "Dolorem", "author": "JK Rowling", "price": 1000, "quantity": 10 } }'

Response :

{ "code": 201, "data": { "bookDto": { "catalogItemId": 3, "skuId": 3, "isbn": "100000000", "title": "Dolorem", "author": "JK Rowling", "price": 1000.0, "quantity": 10 } }, "error": null }

{ "code": 400, "data": null, "error": { "code": 400, "message": "Field isbn is requuired" } }

Search Book

Searches books on the basis of given filters. Title and Author searches allow for partial matches. Returns paginated results, pageNumber and pageSize are mandatory parameters. pageNumber starts from 0.

curl --request GET 'localhost:9000/books?pageNumber=0&pageSize=10&isbn=100000001&title=Dolorem&author=Rowling' --data-raw ''

Response :

{ "code": 200, "data": { "books": [ { "catalogItemId": 3, "skuId": 3, "isbn": "100000000", "title": "Dolorem", "author": "JK Rowling", "price": 1000.0, "quantity": null }, { "catalogItemId": 2, "skuId": 2, "isbn": "100000000", "title": "Dolorem", "author": "Latino", "price": 550.0, "quantity": null } ], "totalCount": 2 }, "error": null }

Create Purchase

Creates a purchase against a sku Id. If book count becomes 0, it adds 1 book to the DB.

curl --request POST 'localhost:9000/purchases' --header 'Content-Type: application/json' --data-raw '{ "skuId": 1, "quantity": 5 }'

Response:

{ "code": 201, "data": { "purchase": { "purchaseId": 6, "skuId": 1, "quantityBought": 1, "price": 1000.0 } }, "error": null }

{ "code": 400, "data": null, "error": { "code": 400, "message": "Not enough stocks available" } }

Fetch Media Coverage

Fetches media coverage given a isbn(as path variable)

curl --request GET 'localhost:9000/mediaCoverage/100000001'

Response:

{ "code": 200, "data": [ { "title": "eum et est occaecati" }, { "title": "dolorem eum magni eos aperiam quia" }, { "title": "dolorem dolore est ipsam" }, { "title": "nesciunt iure omnis dolorem tempora et accusantium" }, { "title": "in quibusdam tempore odit est dolorem" }, { "title": "dolorum ut in voluptas mollitia et saepe quo animi" }, { "title": "voluptatem eligendi optio" }, { "title": "asperiores ea ipsam voluptatibus modi minima quia sint" }, { "title": "maxime id vitae nihil numquam" }, { "title": "est et quae odit qui non" }, { "title": "doloremque illum aliquid sunt" }, { "title": "qui explicabo molestiae dolorem" }, { "title": "fuga nam accusamus voluptas reiciendis itaque" }, { "title": "eos dolorem iste accusantium est eaque quam" }, { "title": "commodi ullam sint et excepturi error explicabo praesentium voluptas" }, { "title": "ut numquam possimus omnis eius suscipit laudantium iure" }, { "title": "aut quo modi neque nostrum ducimus" }, { "title": "soluta aliquam aperiam consequatur illo quis voluptas" }, { "title": "sit asperiores ipsam eveniet odio non quia" }, { "title": "voluptatum itaque dolores nisi et quasi" }, { "title": "voluptas blanditiis repellendus animi ducimus error sapiente et suscipit" }, { "title": "aliquid eos sed fuga est maxime repellendus" }, { "title": "voluptatem laborum magni" }, { "title": "et iusto veniam et illum aut fuga" }, { "title": "enim unde ratione doloribus quas enim ut sit sapiente" }, { "title": "dignissimos eum dolor ut enim et delectus in" }, { "title": "doloremque officiis ad et non perferendis" }, { "title": "pariatur consequatur quia magnam autem omnis non amet" }, { "title": "labore in ex et explicabo corporis aut quas" }, { "title": "tempora rem veritatis voluptas quo dolores vero" }, { "title": "beatae soluta recusandae" }, { "title": "laboriosam dolor voluptates" }, { "title": "temporibus sit alias delectus eligendi possimus magni" } ], "error": null }

{ "code": 404, "data": null, "error": { "code": 404, "message": "Books not found" } }

Running the Project

1. Make sure you have mvn and docker set up
2. navigate to the project directory
3. run command mvn clean install
4. run command docker build -t bookstore-springbootapp .
5. run command docker-compose up
6. The service will be running on port 9000