Hello I have a question regarding the retrieval of JSON fiel kotlinlang #apollo-kotlin

Hello, I have a question regarding the retrieval of JSON fields. I am in the context of data extraction from a GraphQL API. The data is read via Apollo-Kotlin before being stored in a BigQuery database. The API has a generic field that allows storing user data that may not be known in advance. This field is defined as being of JSON type. I want to retrieve the data without any transformation to process it later. Is it possible to retrieve the JSON string without any transformation? Any help is truly appreciated,

mbonnin

11/07/2023, 8:19 AM

It depends how your json field is transmitted over the wire. Usually

JSON

custom scalars are transmitted like so:

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{
  "data": {
    "jsonField": {
      "key": "value"
    }
  }
}

In that case, you can use

AnyAdapter

to map it to a Kotlin

Any

that you can cast to

Map<String, Any?>

The other solution is if it's ttansmitted like so:

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{
  "data": {
    "jsonField": "{ \"key\": \"value\" }"
  }
}

(less common)

In that case, you can use

StringAdapter

to map it to a Kotlin

String

Actually you don't need to use

AnyAdapter

StringAdapter

because the runtime will do this by default and present you with an

Any

type that you can either cast to a

Map

String

If you want to serialize a

Map

back to JSON, you can use something like so:

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buildJsonString { 
    AnyAdapter.toJson(this, CustomScalarAdapters.Empty, map)
  }

But you have to parse the JSON in all cases because the parser needs to know where the JSON field stops

gaetan

11/07/2023, 9:53 AM

Thanks a lot Martin, I will try that.

👍 1

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