Sign in with Apple Java User Verification

Question

I\'ve implemented the app side of the new apple feature \"Sign in with Apple\" but i\'m unable to verificate with authorizationCode in my backend. My backend is written in j

Answer 1

I had an error too but after some tweaks, its working, find my tweak below, note, its in kotlin

   private suspend fun getPrivateKey(): Status {

    return awaitBlocking {
        val authKeyFile = appleConfig.getString("auth_private_key_file", "")

        val authTokenFilePath = getDataDir()!!.resolve(authKeyFile).absolutePath

        val pemParser = PEMParser(FileReader(authTokenFilePath))
        val converter = JcaPEMKeyConverter()
        val obj = pemParser.readObject() as PrivateKeyInfo

        val privateKey = converter.getPrivateKey(obj)

        successStatus(data = privateKey)
    }
}


 /**
 * generateSecretKey
 */
suspend fun generateSecretKey() : Status{

    val getAuthPrivateKey = getPrivateKey()

    if(getAuthPrivateKey.isError()){
        logger.fatal(getAuthPrivateKey.message)
        return errorStatus("system_busy")
    }

    val privateKeyData =  getAuthPrivateKey.getData()

    val clientId = "com.company.app"

    //team id found in apple developer portal
    val teamId = appleConfig.getString("team_id","")

    //apple sign in key ID found in app developer portal
    val authKeyId = appleConfig.getString("auth_key_id","")


    val header = mutableMapOf(
            "alg" to "E256",
            "kid" to authKeyId
    )

    val now = Instant.now().epochSecond

    val claims = mutableMapOf(
            "iss"   to teamId,
            "iat"  to now,
            "exp"  to now + 86400*180,
            "aud"  to "https://appleid.apple.com",
            "sub" to clientId
    )

    println("header - $header")
    println("claims - $claims")

   val token = Jwts.builder()
                .setHeader(header)
                .setClaims(claims)
                .signWith(privateKeyData,SignatureAlgorithm.ES256)
                .compact();


    return successStatus(data = token)
} //end fun





    /**
     * fetchApplePublicKeys
     */
private suspend fun fetchAccessToken(authInfo: JsonObject): Status {
    return  try{

        val authCode = authInfo.getString("auth_code")
        val clientIdToken = authInfo.getString("id_token")

        val accessTokenEndpoint = 
appleConfig.getString("access_token_endpoint")

        val secretKeyTokenStatus = generateSecretKey()

        if(secretKeyTokenStatus.isError()){
            logger.fatal(secretKeyTokenStatus.message)
            return errorStatus("system_busy")
        }

        val clientSecret = secretKeyTokenStatus.getData()

        val redirectUrl = ""

        val clientId = appleConfig.getString("client_id")


        val formData = MultiMap.caseInsensitiveMultiMap()

        formData.add("client_secret",clientSecret)
                .add("client_id",clientId)
                .add("redirect_uri",redirectUrl)
                .add("grant_type","authorization_code")
                .add("code",authCode)

        println("accessTokenEndpoint - $accessTokenEndpoint")
        println("formData - $formData")

        val responseData  = httpClient(this::class)
                .postAbs(accessTokenEndpoint)
                .putHeader("Content-Type","application/x-www-form-urlencoded")
                .sendFormAwait(formData)
                .bodyAsJsonObject()

        println("responseData - ${responseData}")

        if(responseData.containsKey("error")){
            logger.fatal(responseData.getString("error"))
            return errorStatus("social_auth_failed")
        }

        //val responseIdToken = responseData.getString("id_token","")

       return successStatus(data = responseData)
    } catch (e: Exception){
        logger.fatal(e.message,e)
        errorStatus("system_busy")
    }
}