带接口的KTor Gson DataConversion
带接口的KTor Gson DataConversion
提问于 2018-11-17 11:47:37
我正在尝试注册PubicKey接口，以便在KTor中进行数据转换，这样我就可以很容易地接收到这样的公钥：
data class StoreRequest(
val publicKey: PublicKey
)
...
val publicKey: PublicKey = call.receive<StoreRequest>().publicKey为此，我使用了以下页面：https://ktor.io/servers/features/data-conversion.html
我注册了这个数据转换器：
convert<PublicKey> {
decode { values, _ ->
// When I add a breakpoint here it won't be reached.
values.singleOrNull()?.let { key ->
val encryptedKey = Base64.getDecoder().decode(key.split(" ")[1])
val inputStream = DataInputStream(ByteArrayInputStream(encryptedKey))
val format = String(ByteArray(inputStream.readInt()).also(inputStream::readFully))
if (format != "ssh-rsa") throw RuntimeException("Unsupported format")
val publicExponent = ByteArray(inputStream.readInt()).also(inputStream::readFully)
val modulus = ByteArray(inputStream.readInt()).also(inputStream::readFully)
val spec = RSAPublicKeySpec(BigInteger(modulus), BigInteger(publicExponent))
val keyFactory = KeyFactory.getInstance("RSA")
keyFactory.generatePublic(spec)
}
}
}但由于某种原因，Gson抱怨是因为我使用的是一个接口：
java.lang.RuntimeException: Unable to invoke no-args constructor for interface java.security.PublicKey. Register an InstanceCreator with Gson for this type may fix this problem`因此，我猜我需要为初始值创建一个InstanceCreator。这是我创建的初始PublicKey类：
class PkTest : PublicKey {
override fun getAlgorithm(): String = ""
override fun getEncoded(): ByteArray = ByteArray(0)
override fun getFormat(): String = ""
}
...
install(ContentNegotiation) {
gson {
setPrettyPrinting()
registerTypeAdapter(PublicKey::class.java, InstanceCreator<PublicKey> { PkTest() // This is called when I add a breakpoint })
}
}但这也没用！这是我得到的例外：
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 2 column 16 path $.publicKey由于某些原因，它希望提供的密钥是JSON对象，而我提供的是：
{
"publicKey": "ssh-rsa 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 dynmem@memmen.frl"
}我如何“欺骗”GSON在PublicKey中接受字符串？还是我做错了什么？
我认为GSON希望将JSON对象序列化为PublicKey。但我想让它接受String。我认为这是可能的，因为像UUID和Date这样的类工作得很好.
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-11-17 12:41:38
我解决了！我没有使用InstanceCreator，而是使用了JsonDeserializer
install(ContentNegotiation) {
gson {
setPrettyPrinting()
registerTypeAdapter(PublicKey::class.java, JsonDeserializer<PublicKey> { json, _, _ ->
// TODO some type checking.
val key = json.asString
val encryptedKey = Base64.getDecoder().decode(key.split(" ")[1])
val inputStream = DataInputStream(ByteArrayInputStream(encryptedKey))
val format = String(ByteArray(inputStream.readInt()).also(inputStream::readFully))
if (format != "ssh-rsa") throw RuntimeException("Unsupported format")
val publicExponent = ByteArray(inputStream.readInt()).also(inputStream::readFully)
val modulus = ByteArray(inputStream.readInt()).also(inputStream::readFully)
val spec = RSAPublicKeySpec(BigInteger(modulus), BigInteger(publicExponent))
val keyFactory = KeyFactory.getInstance("RSA")
keyFactory.generatePublic(spec)
})
}
}这部分可以完全移除：
convert<PublicKey> {
decode { values, _ ->
...
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/53350924
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