I have looked at a lot of articles but can't seem to figure out the answer. The problem being is that I get a json file like this from my api:
{
"forecast": {
"2020-01-04": {
"date": "2020-01-04",
"mintemp": 7,
"maxtemp": 11,
"avgtemp": 9,
"hourly":
...
}
}
}
The problem is that the "key" in this JSON is always the day of today (2020-01-04). The way I do this now is like this:
data class ForecastDaysContainer(
#SerializedName("2020-01-04")
var forecastday1: FutureWeatherEntry,
#SerializedName("2020-01-05")
val forecastday2: FutureWeatherEntry,
#SerializedName("2020-01-06")
val forecastday3: FutureWeatherEntry,
#SerializedName("2020-01-07")
val forecastday4: FutureWeatherEntry,
#SerializedName("2020-01-08")
val forecastday5: FutureWeatherEntry,
#SerializedName("2020-01-09")
val forecastday6: FutureWeatherEntry,
#SerializedName("2020-01-10")
val forecastday7: FutureWeatherEntry
)
This of course results in me changing the dates every day manually.
Is there any way I can set the #SerializedName to the date of today? When I try this with:
LocalDate.now().toString()
I get the error:
An annotation argument must be a compile-time constant
I can't seem to find a decent fix for this in Kotlin.
It is not possible to have annotation data to be created dynamically. So you need to think it the other way around. With Gson you could try to implement custom JsonDeserializer that parses fields dynamically by that date value.
However I think that most convenient way would be to use Map as comment suggests. If you can make your ForecastDaysContainer like this:
data class ForecastDaysContainer(
var forecast : Map<String, FutureWeatherEntry>
)
When deserialized you will then have a Map that contains possibly many days with the date as the key. So like:
val container = gson.fromJson(json, ForecastDaysContainer::class.java);
val forecast = container.forecast.get("2020-01-04");
Gson has parse() method for that.
val key = "2020-01-04" // This is generated, probably?
val json = JsonParser().parse(jsonString)
val result = json.asJsonObject["forecast"].asJsonObject[key]
Related
override def accessToken(): ServiceCall[RequestTokenLogIn, Done] = {
request=>
val a=request.oauth_token.get
val b=request.oauth_verifier.get
val url=s"https://api.twitter.com/oauth/access_token?oauth_token=$a&oauth_verifier=$b"
ws.url(url).withMethod("POST").get().map{
res=>
println(res.body)
}
The output which I am getting on terminal is
oauth_token=xxxxxxxxx&oauth_token_secret=xxxxxxx&user_id=xxxxxxxxx&screen_name=xxxxx
I want to convert this response in json format.like
{
oauth_token:"",
token_secret:"",
}
When Calling res.json.toString its not converting into jsValue.
Is there any other way or am I missing something?
According to the documentation twitter publishes, it seems that the response is not a valid json. Therefore you cannot convert it automagically.
As I see it you have 2 options, which you are not going to like. In both options you have to do string manipulations.
The first option, which I like less, is actually building the json:
print(s"""{ \n\t"${res.body.replace("=", "\": \"").replace("&", "\"\n\t\"")}" \n}""")
The second option, is to extract the variables into a case class, and let play-json build the json string for you:
case class TwitterAuthToken(oauth_token: String, oauth_token_secret: String, user_id: Long, screen_name: String)
object TwitterAuthToken {
implicit val format: OFormat[TwitterAuthToken] = Json.format[TwitterAuthToken]
}
val splitResponse = res.body.split('&').map(_.split('=')).map(pair => (pair(0), pair(1))).toMap
val twitterAuthToken = TwitterAuthToken(
oauth_token = splitResponse("oauth_token"),
oauth_token_secret = splitResponse("oauth_token_secret"),
user_id = splitResponse("user_id").toLong,
screen_name = splitResponse("screen_name")
)
print(Json.toJsObject(twitterAuthToken))
I'll note that Json.toJsObject(twitterAuthToken) returns JsObject, which you can serialize, and deserialize.
I am not familiar with any option to modify the delimiters of the json being parsed by play-json. Given an existing json you can manipulate the paths from the json into the case class. But that is not what you are seeking for.
I am not sure if it is requires, but in the second option you can define user_id as long, which is harder in the first option.
Using jackson library I read json data from a file (each row of file is a JSON object) an parse it to a map object of String and Any. My goal is to save specified keys (id and text) to a collection.
val input = scala.io.Source.fromFile("data.json").getLines()
val mapper = new ObjectMapper() with DefaultScalaModule
val data_collection = mutable.HashMap.empty[Int, String]
for (i <- input){
val parsedJson = mapper.readValue[Map[String, Any]](i)
data_collection.put(
parsedJson.get("id"),
parsedJson.get("text")
)
But as the values in the parsedJson map have the Any type, getting some keys like id and text, it returns Some(value) not just the value with the appropriate type. I expect the values for the id key to be Integer and values for the text to be String.
Running the code I got the error:
Error:(31, 23) type mismatch;
found : Option[Any]
required: Int
parsedJson.get("id"),
Here is a sample of JSON data in the file:
{"text": "Hello How are you", "id": 1}
Is it possible in Scala to parse id values to Int and text values to String, or at least convert Some(value) to value with type Int or String?
If you want to get a plain value from a Map instead of a Option you can use the () (apply) method - However it will throw an exception if the key is not found.
Second, Scala type system is static not dynamic, if you have an Any that's it, it won't change to Int or String at runtime, and the compiler will fail - Nevertheless, you can cast them using the asInstanceOf[T] method, but again if type can't be casted to the target type it will throw an exception.
Please note that even if you can make your code work with the above tricks, that code wouldn't be what you would expect in Scala. There are ways to make the code more typesafe (like pattern matching), but parsing a Json to a typesafe object is an old problem, I'm sure jackson provides a way to parse a json into case class that represent your data. If not take a look to circe it does.
Try the below code :
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import
com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
val input = scala.io.Source.fromFile("data.json").getLines()
val mapper = new ObjectMapper() with ScalaObjectMapper
mapper.registerModule(DefaultScalaModule)
val obj = mapper.readValue[Map[String, Any]](input)
val data_collection = mutable.HashMap.empty[Int, String]
for (i <- c) {
data_collection.put(
obj.get("id").fold(0)(_.toString.toInt),
obj.get("text").fold("")(_.toString)
)
}
println(data_collection) // Map(1 -> Hello How are you)
I have a JSON string like this:
{"id":"111","name":"abc","ids":["740"],"data":"abc"}
I want to cut off the field "ids", however I don't know apriori the values like ["740"]. So, it might be e.g. ["888,222"] or whatever. The goal is to get the json string without the field "ids".
How to do it? Should I use JackMapper?
EDIT:
I tried to use JackMapper as JacksMapper.readValue[Map[String, String]](jsonString)to get only fields that I need. But the problem is that"ids":["740"]` throws the parsing error because it's an array. So, I decided to cut off this field before parsing, though it's an ugly solution and ideally I just want to parse the json string into Map.
Not sure what JackMapper is, but if other libraries are allowed, my personal favourites would be:
Play-JSON:
val jsonString = """{"id":"111","name":"abc","ids":["740"],"data":"abc"}"""
val json = Json.parse(jsonString).as[JsObject]
val newJson = json - "ids"
Circe:
import io.circe.parser._
val jsonString = """{"id":"111","name":"abc","ids":["740"],"data":"abc"}"""
val json = parse(jsonString).right.get.asObject.get // not handling errors
val newJson = json.remove("ids")
Note that this is the minimal example to get you going which doesn't handle bad input etc.
JSON to Parse: http://www.dota2.com/jsfeed/heropickerdata?v=18874723138974056&l=english
Hero Class and JSON Serialization
case class Hero(
var id:Option[Int],
name: String,
bio: String,
var trueName:Option[String]
){}
implicit val modelReader: Reads[Hero] = Json.reads[Hero]
Reading Data
val future: Future[play.api.libs.ws.Response] = WS.url("http://www.dota2.com/jsfeed/heropickerdata?v=18874723138974056&l=english").get()
val json = Json.parse(Await.result(future,5 seconds).body).as[Map[String, Hero]]
var i = 1
json.foreach(p => {
p._2.trueName = Some(p._1)
p._2.id = Some(i)
p._2.commitToDatabase
i += 1
})
I need to get the id of each hero. The order of heros in the json matches their id. Obviously a map is unordered and wont work. Does anyone have any other ideas?
I have tried to use a LinkedHashMap. I even tried to make an implicit Reads for LinkedHashMap but I've failed. If anyone thinks that this is the answer then would you please give me some guidance?
It keeps just saying "No Json deserializer found for type scala.collection.mutable.LinkedHashMap[String,models.Hero]. Try to implement an implicit Reads or Format for this type.". I have the trait imported into the file i'm trying to read from. I have a funny feeling that the last line in my Reads is the problem. i think I can't just do the asInstanceOf, however I have no other ideas of how to do this reads.
LinkedHashMap Implicit Reads Code: http://pastebin.com/cf5NpSCX
You can try extracting data in order from the JsObject returned by Json.parse directly, possibly like this:
val json = Json.parse(Await.result(future,5 seconds).body)
val heroes: Map[String, Hero] = json match {
case obj: JsObject =>
obj.fields.zipWithIndex.map{ case ((name: String, heroJson: JsValue), id) =>
heroJson.asOpt[Hero].map{ _.copy(id = Some(id)) }
}.flatten.toMap
case _ = > Seq.empty
}
I don't believe you'll need an order-preserving map anymore since the ids are generated and fixed.
I have a string that is a Json array of two objects.
> val ss = """[ {"key1" :"value1"}, {"key2":"value2"}]"""
I want to use the Play Json libraries to deserialize it and create a map from the key values to the objects.
def deserializeJsonArray(ss:String):Map[String, JsValue] = ???
// Returns Map("value1" -> {"key1" :"value1"}, "value2" -> {"key2" :"value2"})
How do I write the deserializeJsonArray function? This seems like it should be easy, but I can't figure it out from either the Play documentation or the REPL.
I'm a bit rusty, so please forgive the mess. Perhaps another overflower can come in here and clean it up for me.
This solution assumes that the JSON is an array of objects, and each of the objects contains exactly one key-value pair. I would highly recommend spicing it up with some error handling and/or pattern matching to validate the parsed JSON string.
def deserializeJsonArray(ss: String): Map[String, JsValue] = {
val jsObjectSeq: Seq[JsObject] = Json.parse(ss).as[Seq[JsObject]]
val jsValueSeq: Seq[JsValue] = Json.parse(ss).as[Seq[JsValue]]
val keys: Seq[String] = jsObjectSeq.map(json => json.keys.head)
(keys zip jsValueSeq).toMap
}