Reward System Code Challenge

A Clojure solution for the Nubank's Reward System Code Challenge.

Build and running

This solution uses Leiningen as it's build tool. The FILE argument mentioned in the next sections is optional (more details here). If no FILE is supplied, the registry starts empty.

REPL

1. lein repl
2. => (def dev-server (run-dev FILE))

Leiningen

lein run FILE OR lein run-dev FILE

API

Get user's info

Gets user's information.

Request

GET /users/:id

Parameters

• :id - User id (string)

Response format

{
  "id": "1",       // :id
  "score": 1.0,    // current score
  "invited": ["2"] // ids of the users invited by this one
}

Return codes

• 200 OK - Success
• 400 Bad Request - :id is invalid
• 404 Not Found - :id doesn't exist

Invite a new user

Invites a new user and returns the updated inviter.

Request

POST /users/:inviter/invite

Body

{
  "invitee": :invitee
}

Parameters

• :inviter - The inviter's user id (string)
• :invitee - The invitee's user id (string)

Response format

{
  "id": "1",           // :id
  "score": 1.0,        // current score
  "invited": ["2","3"] // ids of the users invited by this one
}

Return codes

• 200 OK - Success
• 400 Bad Request - :invitee/:inviter is missing or invalid
• 404 Not Found - :inviter doesn't exist

Ranking

Gets the current ranking. The response list is sorted by score (desc) and id (asc).

Request

GET /ranking

Response format

[
    {"id":"1", "score":1.5},
    {"id":"2", "score":0},
    {"id":"3", "score":0},
    {"id":"4", "score":0}
]

Return codes

• 200 OK - Success

Testing

The tests were implemented using midje. The whole test suite can be run using the lein midje command.

Production/Deployment

This code can be deployed in many fashions. Here are some options...

Heroku

This code can be easily deployed to Heroku. Just click this button:

Docker

1. Build an uberjar: lein uberjar
2. Build a Docker image: sudo docker build -t reward-system
3. Run the Docker image: docker run -p 8080:8080 reward-system

JAR

1. Build an uberjar: lein uberjar
2. Run it: java -jar target/reward-system-standalone.jar [FILE]

Note

Both Heroku and Docker starts the application with the default input file.

Input file

Optionally, you can supply an input file from where the application will read the invitation records and populate the registry.

The file should have one invitation per line, in the inviterId inviteeId format. Both inviterId and inviteeId will be handled as strings.

Example:

1 2
1 abc
abc c
1 c
2 4

This application provides a input file sample, which can be found at resources/input.txt.