kilink
commented
2 years ago Jackson needs to be told explicitly what concrete type to deserialize to for interfaces and abstract types such as PageInfo and ConnectionCursor. This can be done by registering a custom module and calling addAbstractTypeMapping. Jackson would still have trouble deserializing to DefaultPageInfo, so you would need a ValueInstantiator or Deserializer to handle that.
import com.fasterxml.jackson.databind.DeserializationConfig
import com.fasterxml.jackson.databind.DeserializationContext
import com.fasterxml.jackson.databind.JavaType
import com.fasterxml.jackson.databind.PropertyMetadata
import com.fasterxml.jackson.databind.PropertyName
import com.fasterxml.jackson.databind.deser.CreatorProperty
import com.fasterxml.jackson.databind.deser.SettableBeanProperty
import com.fasterxml.jackson.databind.deser.ValueInstantiator
import graphql.relay.ConnectionCursor
import graphql.relay.DefaultPageInfo
class DefaultPageInfoValueInstantiator : ValueInstantiator.Base(DefaultPageInfo::class.java) {
override fun canCreateFromObjectWith(): Boolean {
return true
}
override fun getFromObjectArguments(config: DeserializationConfig): Array<SettableBeanProperty> {
val connectionCursorType = config.constructType(ConnectionCursor::class.java)
val booleanType = config.constructType(Boolean::class.java)
return arrayOf(
creatorProp("startCursor", connectionCursorType, 0),
creatorProp("endCursor", connectionCursorType, 1),
creatorProp("hasPrevious", booleanType, 2),
creatorProp("hasNext", booleanType, 3)
)
}
override fun createFromObjectWith(ctxt: DeserializationContext, args: Array<out Any>): Any {
return DefaultPageInfo(args[0] as ConnectionCursor, args[1] as ConnectionCursor, args[2] as Boolean, args[3] as Boolean)
}
private fun creatorProp(name: String, type: JavaType, index: Int): CreatorProperty {
return CreatorProperty.construct(PropertyName.construct(name), type, null, null, null, null, index, null, PropertyMetadata.STD_OPTIONAL)
}
}And the Jackson module would look like this:
import com.fasterxml.jackson.databind.module.SimpleModule
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer
import graphql.relay.ConnectionCursor
import graphql.relay.DefaultConnectionCursor
import graphql.relay.DefaultPageInfo
import graphql.relay.PageInfo
class GraphQLModule : SimpleModule() {
init {
addAbstractTypeMapping(PageInfo::class.java, DefaultPageInfo::class.java)
addAbstractTypeMapping(ConnectionCursor::class.java, DefaultConnectionCursor::class.java)
addSerializer(DefaultConnectionCursor::class.java, ToStringSerializer.instance)
addValueInstantiator(DefaultPageInfo::class.java, DefaultPageInfoValueInstantiator())
}
}Example usage:
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.fasterxml.jackson.module.kotlin.readValue
import graphql.relay.PageInfo
data class Response(val pageInfo: PageInfo)
val objectMapper = jacksonObjectMapper()
.registerModule(GraphQLModule())
val response = objectMapper.readValue<Response>("""{"pageInfo": {"endCursor": "bar", "hasPrevious": true, "hasNext": true}}""")
println(response)
// prints Response(pageInfo=DefaultPageInfo{ startCursor=null, endCursor=bar, hasPreviousPage=true, hasNextPage=true})
println("json = " + objectMapper.writeValueAsString(response))
// print json = {"pageInfo":{"startCursor":null,"endCursor":"bar","hasPreviousPage":true,"hasNextPage":true}}I have actually run into the same issue, particularly when writing tests for server-side responses. Now whether this is something that belongs in dgs-codegen (or elsewhere?), I am not sure. @berngp thoughts?
srinivasankavitha
Using the schema found here (also attached as txt) schema.txt I've generated a query API.
I make the following query (generated by the query API):
I get this response back:
Then when I attempt to parse the
siteobject into a type generated by the codegen plugin...I get this
This is my codegen configuration, via the community maven port
and these are the versions of the dgs libraries I'm using