Receipt-Api

This project handles GET and POST requests. For POST request this project takes a JSON receipt and returns a JSON object with an ID. For the GET request, with provided ID of a receipt returns a JSON response with points earned.

Getting Started

Before running this project on your local machine for development and testing, complete the following steps.

Prerequisites

Before running the server, have Go and Git installed on your machine. The project is built on Go version 1.22.0. Go installation offical website Git installtion

Installation

To set up the project, clone the repositoy to your local machine:

git clone [email protected]:zafs23/Receipt-Api.git
cd receipt-api

Then, run the server using:

go run main.go

The API will listen to http://localhost:8080 to handle GET and POST request.

Services

POST request

• endpoint: /receipts/process
• Payload: Receipt JSON
• Response: JSON containing an id for the receipt. example response:

  { "id": "9aedae7d3b59b2ba3b364924bf39f2f797653b4eb4b7fb17ec104bf7ab064b9b" }

GET request

• endpoint: /receipts/{id}/points
• Response: A JSON object containing the number of points awarded. example response:

  { "points": 32 }

Payload Example

   {
   "retailer": "Target",
   "purchaseDate": "2022-01-01",
   "purchaseTime": "13:01",
   "items": [
       {
       "shortDescription": "Mountain Dew 12PK",
       "price": "6.49"
       },{
       "shortDescription": "Emils Cheese Pizza",
       "price": "12.25"
       },{
       "shortDescription": "Knorr Creamy Chicken",
       "price": "1.26"
       },{
       "shortDescription": "Doritos Nacho Cheese",
       "price": "3.35"
       },{
       "shortDescription": "   Klarbrunn 12-PK 12 FL OZ  ",
       "price": "12.00"
       }
   ],
   "total": "35.35"
   }

Expected points:

    Total Points: 28
    Breakdown:
        6 points - retailer name has 6 characters
        10 points - 4 items (2 pairs @ 5 points each)
        3 Points - "Emils Cheese Pizza" is 18 characters (a multiple of 3)
                    item price of 12.25 * 0.2 = 2.45, rounded up is 3 points
        3 Points - "Klarbrunn 12-PK 12 FL OZ" is 24 characters (a multiple of 3)
                    item price of 12.00 * 0.2 = 2.4, rounded up is 3 points
        6 points - purchase day is odd
    + ---------
    = 28 points

Service Logic

These rules collectively define how many points should be awarded to a receipt.

• One point for every alphanumeric character in the retailer name.
• 50 points if the total is a round dollar amount with no cents.
• 25 points if the total is a multiple of 0.25.
• 5 points for every two items on the receipt.
• If the trimmed length of the item description is a multiple of 3, multiply the price by 0.2 and round up to the nearest integer. The result is the number of points earned.
• 6 points if the day in the purchase date is odd.
• 10 points if the time of purchase is after 2:00 pm and before 4:00 pm.

Assumptions and Design Scope

Assumptions in the design

• Each short description assumed to be 1-50 characters long
• When determining the total is multiple of 0.25, the tolerance is assumed to be 0..00001
• Expect at most two decimal places in the item price

Additional to the handler, a controller could be implemented for more complex business logic. But for this simple project, no controller logic is added.

Scalability and Memory Usage

To simulate scalability in the in-memory storage system, data sharding is implemented with the highest of 10 shards. To keep the memory usage limited, the generated ID is unique for identical payloads and stored in a cache for better performance.

Testing

To execute the automated tests, run the following command from the project directory:

go test -v ./tests/...