How to read a JSON file into a Map, using Scala - scala

Question

How can I read a JSON file into a Map, using Scala. I've been trying to accomplish this but the JSON I am reading is nested JSon and I have not found a way to easily extract the JSON into keys because of that. Scala seems to be wanting to also convert the nested JSON String into an object. Instead, I want the nested JSON as a String "value". I am hoping someone can clarify or give me a hint on how I might do this.
My JSON source might look something like this:
{
"authKey": "34534645645653455454363",
"member": {
"memberId": "whatever",
"firstName": "Jon",
"lastName": "Doe",
"address": {
"line1": "Whatever Rd",
"city": "White Salmon",
"state": "WA",
"zip": "98672"
},
"anotherProp": "wahtever",
}
}
I want to extract this JSON into a Map of 2 keys without drilling into the nested JSON. Is this possible? Once I have the Map, my intention is to add the key-values to my POST request headers, like so:
val sentHeaders = Map("Content-Type" -> "application/javascript",
"Accept" -> "text/html", "authKey" -> extractedValue,
"member" -> theMemberInfoAsStringJson)
http("Custom headers")
.post("myUrl")
.headers(sentHeaders)

Answer 1

Since the question is tagged 'gatling', behind the curtains this lib depends on Jackson/fasterxml for JSON processing, so we can make use of it.
There is no way to retrieve a nested structured part of JSON as String directly, but with very few additional code the result can still be achieved.
So, having the input JSON:
val json = """{
| "authKey": "34534645645653455454363",
| "member": {
| "memberId": "whatever",
| "firstName": "Jon",
| "lastName": "Doe",
| "address": {
| "line1": "Whatever Rd",
| "city": "White Salmon",
| "state": "WA",
| "zip": "98672"
| },
| "anotherProp": "wahtever"
| }
|}""".stripMargin
A Jackson's ObjectMapper can be created and configured for use in Scala:
// import com.fasterxml.jackson.module.scala.DefaultScalaModule
val mapper = new ObjectMapper().registerModule(DefaultScalaModule)
To parse the input json easily, a dedicated case class is useful:
case class SrcJson(authKey: String, member: Any) {
val memberAsString = mapper.writeValueAsString(member)
}
We also include val memberAsString in it, which will contain our target JSON string, obtained through a reverse conversion from initially parsed member which actually is a Map.
Now, to parse the input json:
val parsed = mapper.readValue(json, classOf[SrcJson])
The references parsed.authKey and parsed.memberAsString will contain the researched values.

Answer 2

have a look at the scala play library - it has support for handling JSON. From what you describe, it should be pretty straightforward to read in the JSON and get the string value from any desired node.
Scala Play - JSON