trjhtr

I am writing API in Kotlin - this is my first code in this language. I implemented a very primitive 'player' endpoint. I was wondering if I am doing everything ok (please don't mind the static variables - I will put them in the database later)

import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.*
import pl.domain.Player
import pl.rest.dto.PlayerDto

@RestController
@RequestMapping("/player")
class PlayerController 

 var players: Map<Long, Player> = mapOf(
 1L to Player(1L, "user1", "password1"),
 2L to Player(2L, "user2", "password2"),
 3L to Player(3L, "user3", "password3")
 )

 @GetMapping("/id")
 fun fetchPlayer(@PathVariable id : Long): ResponseEntity<Player> =
 players[id]?.let ResponseEntity.ok(it) ?: ResponseEntity.notFound().build()

 @PostMapping
 fun createPlayer(@RequestParam username: String, @RequestParam password : String): ResponseEntity<Player> 
 val playerId = (players.size + 1).toLong()
 val player = Player(playerId, username, password)
 players = players.plus(player.id to player)
 return ResponseEntity.ok(player)
 

 @PutMapping
 fun updatePlayer(@RequestBody playerDto: PlayerDto): ResponseEntity<Player> 
 return players[playerDto.id]
 ?.apply 
 username = playerDto.username ?: username
 password = playerDto.password ?: password
 ?.let ResponseEntity.ok(it) ?: ResponseEntity.badRequest().build()
 

 @DeleteMapping("/id")
 fun deletePlayer(@PathVariable id: Long): ResponseEntity<Nothing> 
 players = players.minus(id)
 return ResponseEntity.noContent().build()
 

PlayerDto.kt:

class PlayerDto(var id: Long? = null, var username: String? = null, var password: String? = null)

Player.kt:

data class Player(var id: Long, var username: String, var password: String)

I've two recommendations that probably have more to do with design rather than with code. The first one is to change the API path to players:

@RequestMapping("/players")

I personally like to pluralize resource path names even if it's widely discussed.

The other one is to modify your PUT endpoint in order to also accept resources to be created. That way you would have a single endpoint which accepts a list of players, where players might be new or already have an id. For the first case, the system must create them, for the second, update them. That's also a mather of disussion in the net.