简要介绍

JWT全称:JSON Web Token,是当前使用非常广泛的跨域身份验证方案. 本文介绍在ktor中如何使用JWT.

使用步骤

1. build.gradle中添加依赖(maven也类似)

compile "io.ktor:ktor-auth-jwt:$ktor_version"

2. 添加认证类:Auth

object Auth {
    private const val SECRET_KEY = "secret"
    private val algorithm = Algorithm.HMAC512(SECRET_KEY)
    private const val issuer = "ktor.io"
    private const val validityInMs = 3600*1000 * 10 // 10 hours

    fun makeJwtVerifier(): JWTVerifier = JWT
        .require(algorithm)
        .withIssuer(issuer)
        .build()

    fun sign(name: String): Map<String, String> {
        return mapOf("token" to makeToken(name))
    }

    private fun makeToken(name: String): String = JWT.create()
        .withSubject("Authentication")
        .withIssuer(issuer)
        .withClaim("name", name)
        .withExpiresAt(getExpiration())
        .sign(algorithm)

    private fun getExpiration() = Date(System.currentTimeMillis() + validityInMs)

}

3. 在启动类中启用jwt

private val verifier = Auth.makeJwtVerifier()
install(Authentication) {
        jwt {
            verifier(verifier)
            validate {
                UserIdPrincipal(it.payload.getClaim("name").asString())
            }
        }
    }

4. 登陆时进行校验,校验成功后返回token

routing {
    post("login") {
        val user = call.receive<User>()
        //TODO：校验用户、密码有效性的代码自己写
        call.respond(Auth.sign(user.name))
    }
}

5. 对需要认证后才能访问的接口添加认证关键字authenticate(下面样例是用于访问secret页面的)

routing {
    authenticate {
        route("secret") {
            get {
                val user = call.authentication.principal<UserIdPrincipal>()
                call.respondText("hi ${user?.name}, you are authenticated.", contentType = ContentType.Text.Plain)
            }
        }
    }
}

完整源代码

https://github.com/cxyzy1/ktor_jwt

参考资料

https://github.com/joelsaunders/ktor-starter.git
https://github.com/sjcqs/ktor-quotes.git
https://github.com/QAutomatron/ktor-backend.git
https://github.com/AndreasVolkmann/ktor-auth-jwt-sample.git

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