ktor HTTP API 練習

練習一

Question

爲每一個片斷添加惟一 id，併爲 /snippets 添加一個 DELETE http 動詞，以容許經過身份認證的用戶刪除本身的片斷。

Answer

首先爲每一個片斷添加惟一 id：

data class Snippet(val id: Int, val user: String, val text: String)
val snippets = Collections.synchronizedList(
    mutableListOf(
        Snippet(id = 1, user = "test", text = "hello"),
        Snippet(id = 2, user = "test", text = "world")
    )
)

修改新增片斷的post請求：

authenticate {
                post {
                    val post = call.receive<PostSnippet>()
                    val principal = call.principal<UserIdPrincipal>() ?: error("No principal")
                    snippets += Snippet(snippets.size+1, principal.name, post.snippet.text)
                    call.respond(mapOf("OK" to true))
                }
            }

先測試新增片斷的請求是否正常，ID正確

添加刪除片斷的delete請求：

authenticate {
                delete("/{id}") {
                    val id = call.parameters["id"]
                    val snip = snippets.find { s -> s.id == id?.toInt() }
                    if (snip != null) {
                        snippets.remove(snip)
                        call.respond(mapOf("snippets" to synchronized(snippets) { snippets.toList() }))
                    }
                    else{
                        call.respond(mapOf("msg" to "no such id"))
                    }
                }
            }

添加一個DELETE的HTTP請求測試

DELETE {{host}}/snippets/1
Authorization: Bearer {{auth_token}}

返回結果以下，id爲1的snippets已被刪除