Linktree Challenge

Author: Alessio Palumbo

Problem

Design a REST API to support multiple types of links:

Link types

• Classic
  • Title => no longer than 144 characters
  • Url => may contain query parameters
• Shows List
  • Status => sold out, on sale, not yet on sale
• Music Player
  • Multiple links => requires a link to each platform

Objectives

• The client must be able to create a new link of each type.
• The client must be able to find all links matching a particular userId.
• The client must be able to find links matching a particular userId by dateCreated

Solution

DB schema (postgres)

• users: -- this is just to support links table so we just need an id

  • id UUID NOT NULL (PK)

• links:

  • id UUID NOT NULL (PK)
  • user_id UUID NOT NULL (FK)
  • type CHAR(10) NOT NULL default 'classic'
  • title VARCHAR(144) default NULL
  • url VARCHAR(500) default NULL -- TODO could use shortened urls
  • thumbnail VARCHAR(144) default NULL -- assuming is shortened and stored in an s3 bucket
  • created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
  • TODO if needed an update_at timestamp could be added
  • TODO for the sake of ordering we could have an order_id field

• sublinks:

  • id UUID NOT NULL (PK)
  • link_id UUID NOT NULL (FK)
  • metadata JSONB NOT NULL

Models

Main Link model

• Link --
  • ID string (uuid)
  • UserID string (uuid)
  • Type string ('classic', 'music', 'shows')
  • Title *string
  • URL *string
  • SubLinks []interface{}

Shows List sublink model

• Show:
  • ID string (uuid)
  • Date string -- This could be a time.Time
  • Name string
  • Venue string
  • Location string -- TODO this could be a new struct Address
  • Status Status(string)

Music Player sublink model

• Platform:
  • ID uuid
  • Name string
  • URL string

Examples:

• Classic: Link{ ID: "001", UserID: "43435423", Type: "classic", Title: "First Link", URL: "https://myfirstlink.com/1", }

• Show-Link: Link{ ID: "002", UserID: "34232354", Type: "show", SubLinks: []Show{ Show{ ID: "s001", Date: "Apr 01 2019", Name: "Cats", Venue: "Princess Theatre", Location: "Melbourne", Status: "on-sale", URL: "https://www.ticketmaster.com.au/cats-the-musical-tickets/artist/843992", }, }, }

• Music player: Link{ ID: "003", UserID: "43532454", Type: "music", Title: "All of me - John Legend" URL: "https://www.youtube.com/watch?v=450p7goxZqg", -- This stores the url for the embed default player SubLinks: []Platform{ Platform{ ID: "p001", Name: "Spotify", URL: "https://open.spotify.com/album/1YdXQgntClL3BhIXB0xpgs", }, Platform{ ID: "p002", Name: "SoundCloud", URL: "https://soundcloud.com/johnlegend/all-of-me-3", }, }, }

REST API

Authentication

The Api assumes it can fetch the userID of the request from the authentication middleware

Links Rest

• GET /api/links

  • Query params
    • order_by: created_at:asc,title:desc,type (optional, accepts multiple columns. TODO default to positionID)
  • Responses:
    • 200 OK

      {
          "links": [
              {
                  "id": "001",
                  "type": "classic",
                  "url": "https://myfirstlink.com/1"
              },
              {
                  "id": "002",
                  "type": "show",
                  "url": "https://myfirstlink.com/1",
                  "sublinks": [
                      {
                          "id": "s001",
                          "date": "Apr 01 2019",
                          "venue": "Princess Theatre",
                          "location": "Melbourne",
                          "status": "sold-out"
                      }
                  ]
              }
          ]
      }
      

    • 400 Bad Request
    • 404 Not found (user)

• GET /api/links/{link_id}

  • Responses:
    • 200 OK

      {
          "id": "001",
          "type": "classic",
          "url": "https://myfirstlink.com/1"
      }
      
      

• POST /api/links

  • Request:

    {
        "type": "music",
        "title": "All of me - John Legend",
        "url": "https://www.youtube.com/watch?v=450p7goxZqg",
        "sublinks": [
            {
                "name": "Spotify",
                "url": "https://open.spotify.com/album/1YdXQgntClL3BhIXB0xpgs"
            },
            {
                "name": "SoundCloud",
                "url": "https://soundcloud.com/johnlegend/all-of-me-3"
            }
        ]
    }
    

  • Responses:
    • 201 Created
    • 400 Bad Request

• PUT /api/links/{link_id}

  • Request:

    {
        "type": "classic",
        "title": "My second Link",
        "url": "https://www.mysecondlink.com/2"
    }
    

  • Responses:
    • 200 OK

      {
          "id": "004",
          "type": "classic",
          "title": "My second Link",
          "url": "https://www.mysecondlink.com/2"
      }
      

    • 400 Bad Request

• DELETE /api/links/{link_id} -- Remove link and any sublinks

  • Response:
    • 204 No Responses

SubLinks Rest (Only POST, PUT and DELETE)

• POST /api/links/{link_id}/sublinks

  • Request:

    {
        "name": "Spotify",
        "url": "https://open.spotify.com/album/1YdXQgntClL3BhIXB0xpgs"
    }
    

  • Responses:
    • 201 Created
    • 400 Bad Request

• PUT /api/links/{link_id}/sublinks/{sublink_id}

  • Request:

    {
        "type": "classic",
        "title": "My second Link",
        "url": "https://www.mysecondlink.com/2"
    }
    

  • Responses:
    • 200 OK

      {
          "id": "004",
          "type": "classic",
          "title": "My second Link",
          "url": "https://www.mysecondlink.com/2"
      }
      

    • 400 Bad Request

• DELETE /api/links/{link_id}/sublinks/{sublink_id}

  • Response:
    • 204 No Responses

Language used: Go

Setup

Installing Go (1.12 or higher)

Install Go following the official instructions: https://golang.org/doc/install

Run

• From the console cd into main folder linktree-challenge
• Run go run server.go

Build and Run

• Run go build server.go
• Run ./linktree-challenge

Test

• Run all test go test -v

Notes about using GOPATH

• If running inside a GOPATH on Go 1.11/1.12 use the following command to build and test
  • GO111MODULE=on go run server.go
  • GO111MODULE=on go build .
  • GO111MOdULE=on go test -v