我在尝试解析一些json时收到以下错误消息:
[info] The future returned an exception of type: spray.httpx.PipelineException, with message:
Vector("eba760a81b177051b0520418b4e10596955adb98196c15367a2467ab66a19b5c", 600, "AN51SPP6iZBHFJ3aux1jtn6MMMD13Gh3t7", 500,
["1BXVXP82f7x9YWdWuCaCYwad8ZoYayyRYt"], "76a91473758c13a91699376abb8fe76931bdd9bdc04ee388ac", false)
(of class scala.collection.immutable.Vector). (AddressUnspentTXORequestTest.scala:14)
我不确定这意味着什么。这是我要解析的json片段:
[
{
"transaction_hash": "eba760a81b177051b0520418b4e10596955adb98196c15367a2467ab66a19b5c",
"output_index": 1,
"value": 600,
"asset_id": "AN51SPP6iZBHFJ3aux1jtn6MMMD13Gh3t7",
"asset_quantity": 500,
"addresses": [
"1BXVXP82f7x9YWdWuCaCYwad8ZoYayyRYt"
],
"script_hex": "76a91473758c13a91699376abb8fe76931bdd9bdc04ee388ac",
"spent": false,
"confirmations": 31674
},
{
"transaction_hash": "1f9f6224bee8813135aba622693c78a33b3460e4efdb340174f87fdd8c9d4148",
"output_index": 1,
"value": 600,
"asset_id": "AS6tDJJ3oWrcE1Kk3T14mD8q6ycHYVzyYQ",
"asset_quantity": 200000,
"addresses": [
"1BXVXP82f7x9YWdWuCaCYwad8ZoYayyRYt"
],
"script_hex": "76a91473758c13a91699376abb8fe76931bdd9bdc04ee388ac",
"spent": false,
"confirmations": 35895
}
]
以下是我尝试将其解析为的案例类:
case class UnspentTXO(transaction_hash: String, output_index: Int, value: Long,
asset_id: Option[String], asset_quantity: Option[Long], addresses: List[BitcoinAddress],
script_hex: String, spent: Boolean)
启动请求的方法如下:
def getUnspentTXOs(address: Address): Future[List[UnspentTXO]] = {
val pipeline: HttpRequest => Future[List[UnspentTXO]] =
sendReceive ~> unmarshal[List[UnspentTXO]]
pipeline(Get(host + path + address.value + "/unspents"))
}
最后这就是我解析Json Request的方法:
override def read(value: JsValue): UnspentTXO = {
val Seq(transaction_hash, output_index, locked_satoshies, asset_id, asset_quantity, addresses, script_hex, spent) =
value.asJsObject.getFields("transaction_hash", "value", "asset_id", "asset_quantity", "addresses", "script_hex", "spent")
val assetId = asset_id match {
case JsString(s) => Some(s)
case JsNull => None
case _ => throw new RuntimeException("Asset id should be of type JsString or JsNull, got something else")
}
val assetQuantity = asset_quantity match {
case JsNumber(n) => Some(n.toLong)
case JsNull => None
case _ => throw new RuntimeException("Asset quantity should be JsNull or a JsNumber")
}
// convert JsArray to List[ BitcoinAdress ]
val addressList = addresses match {
case ja: JsArray => {
ja.elements.toList.map( e => BitcoinAddress(e.convertTo[String]))
}
case _ => throw new RuntimeException("address list should be of type JsArray, got something else")
}
UnspentTXO(transaction_hash.convertTo[String], output_index.convertTo[Int], locked_satoshies.convertTo[Long],
assetId, assetQuantity, addressList,
script_hex.convertTo[String], spent.convertTo[Boolean])
}
我认为问题可能是请求返回一个json数组而不仅仅是一个JSON对象,所以我不确定我是否在getUnspentTXOs
内正确处理。错误消息似乎很模糊。似乎spray正在尝试将json字段包装在Vector
内而不是UnspentTXO
case类中。我不知道为什么会发生这种情况。
答案 0 :(得分:2)
您不能只拨打convertTo[ Option[ Long ] ]
和convertTo[ List [ BitcointAddress ] ]
。
这是convertTo
的定义方式,
def convertTo[T :JsonReader]: T = jsonReader[T].read(this)
这意味着......只有T
implicit
typeclass
JsonReader[ T ]
证据的convertTo
类型可以与implicit typeclass
一起使用。
除非您提供适当的spray-json
证据,否则您必须专门处理少数案件。
除此之外,JsObject
过于简约......所以Map[ String, JsValue]
只是getFields
之上的包装,而 def getFields(fieldNames: String*): immutable.Seq[JsValue] =
fieldNames.flatMap(fields.get)(collection.breakOut)
被定义为,< / p>
JsValue
这意味着......它只会忽略其中没有地址的问题字段,并且只返回与所提出的字段相对应的override def read(value: JsValue): UnspentTXO = {
val jsObject = value.asJsObject
// get only non-optional values here
val Seq( transaction_hash, output_index, locked_satoshies, addresses,
script_hex, spent ) =
jsObject.getFields( "transaction_hash", "output_index", "value", "addresses", "script_hex", "spent" )
// Assuming you have imported spray.json._, simple types will work.
// have to handle options differently
// or 2 optional values would mean 4 patterns-matchings of sequences like above.
// jsObject.fields is just a Map[ String, JsValue ]
val assetId = jsObject.fields.get( "asset_id" ) match {
case Some( JsString( s ) ) => Some( s )
case None => None
}
val assetQuantity = jsObject.fields.get( "asset_quantity" ) match {
case Some( JsNumber( n ) ) => Some( n.toLong )
case None => None
}
// convert JsArray to List[ BitcoinAdress ]
val addressList = addresses match {
case ja : JsArray => {
ja.elements.toList.map( BitcoinAddress( _.convertTo[ String ] ) )
}
}
UnspentTXO( transaction_hash.convertTo[ String ], output_index.convertTo[ Int ],
locked_satoshies.convertTo[ Long ], assetId, assetQuantity,
addressList, script_hex.convertTo[ String ], spent.convertTo[ Boolean ] )
}
序列。
因此必须检查可选值是否存在于地图中。或者我们将不得不针对每种可能的情况进行模式匹配(这可能导致很多情况)。
convertTo[ Option[ T ] ]
让convertTo[ List[ T ] ]
和spray.json.DefaultJsonProtocol._
工作的另一种方法是导入implicit
,它为大多数常用类型提供json格式。但即便如此,您的范围内必须有typeclass JsonReader[ T ]
{{1}}的证据。