Ktor 中的表单身份验证

我是新来的Kotlin and Ktor试图查看身份验证部分，所以我得到了以下代码。

路由“/”和“/bye”工作正常，但路由“login”给出空白页面！

package blog

import kotlinx.html.*
import kotlinx.html.stream.*    // for createHTML
import org.jetbrains.ktor.application.*
import org.jetbrains.ktor.auth.*
import org.jetbrains.ktor.features.*
import org.jetbrains.ktor.http.*
import org.jetbrains.ktor.response.*
import org.jetbrains.ktor.routing.*

import org.jetbrains.ktor.request.*   // for request.uri

import org.jetbrains.ktor.html.*
import org.jetbrains.ktor.pipeline.*

import org.jetbrains.ktor.host.*   // for embededServer
import org.jetbrains.ktor.netty.*  // for Netty

fun main(args: Array<String>) {
    embeddedServer(Netty, 8080, watchPaths = listOf("BlogAppKt"), module = Application::module).start()
}

fun Application.module() {
    install(DefaultHeaders)
    install(CallLogging)

    intercept(ApplicationCallPipeline.Call) { 
        if (call.request.uri == "/hi")
            call.respondText("Test String")
    }

    install(Routing) {
        get("/") {
            call.respondText("""Hello, world!<br><a href="/bye">Say bye?</a>""", ContentType.Text.Html)
        }
        get("/bye") {
            call.respondText("""Good bye! <br><a href="/login">Login?</a> """, ContentType.Text.Html)
        }
        route("/login") {
            authentication {
                formAuthentication { up: UserPasswordCredential ->
                    when {
                        up.password == "ppp" -> UserIdPrincipal(up.name)
                        else -> null
                    }
                }
            }

            handle {
                val principal = call.authentication.principal<UserIdPrincipal>()
                if (principal != null) {
                    call.respondText("Hello, ${principal.name}")
                } else {
                        val html = createHTML().html {
                        body {
                            form(action = "/login", encType = FormEncType.applicationXWwwFormUrlEncoded, method = FormMethod.post) {
                                p {
                                    +"user:"
                                    textInput(name = "user") {
                                        value = principal?.name ?: ""
                                    }
                                }

                                p {
                                    +"password:"
                                    passwordInput(name = "pass")
                                }

                                p {
                                    submitInput() { value = "Login" }
                                }
                            }
                        }
                    }
                    call.respondText(html, ContentType.Text.Html)
                }
            }
        }
    }
}

当我禁用下面的身份验证部分时，路由“/login”显示所需的形式，这意味着错误很可能出现在这部分或调用它的方式中？我猜。

            authentication {
                formAuthentication { up: UserPasswordCredential ->
                    when {
                        up.password == "ppp" -> UserIdPrincipal(up.name)
                        else -> null
                    }
                }
            }

您得到的不仅仅是一个空白页面，您还会得到一个 HTTP 状态代码401 (UNAUTHORIZED)。那是因为formAuthentication有四个参数，其中三个具有默认值。您只实现了最后一个（validate，无默认值）：

userParamName: String = "user",
passwordParamName: String = "password",
challenge: FormAuthChallenge = FormAuthChallenge.Unauthorized,
validate: (UserPasswordCredential) -> Principal?

每当你到达/login如果没有正确的凭据，您将获得默认的路由challenge，即FormAuthChallenge.Unauthorized，这是一个401回复。

而不是使用默认值challenge，你可以使用FormAuthChallenge.Redirect。一个需要两条路线的简短示例：

get("/login") {
    val html = """
            <form action="/authenticate" enctype="..."
            REST OF YOUR LOGIN FORM
            </form>
            """
    call.respondText(html, ContentType.Text.Html)
}

route("/authenticate") {
    authentication {
        formAuthentication(challenge = FormAuthChallenge.Redirect({ _, _ -> "/login" })) {
            credential: UserPasswordCredential ->
            when {
                credential.password == "secret" -> UserIdPrincipal(credential.name)
                else -> null
            }
        }
    }

    handle {
        val principal = call.authentication.principal<UserIdPrincipal>()
        val html = "Hello, ${principal?.name}"
        call.respondText(html, ContentType.Text.Html)
    }
}

UPDATE

如果上述方法效果不佳，请定义userid-parameter and password-parameter显然，正如它们出现在form这样做的POST， 如下：

        authentication {
            formAuthentication("user", "pass",
                    challenge = FormAuthChallenge.Redirect({ _, _ -> "/login" })){
                credential: UserPasswordCredential ->
                when {
                credential.password == "secret" -> UserIdPrincipal(credential.name)
                else -> null
                }
            }
        }