Map deserialization inside objects

[mjp91]

As mentioned in gitter:

Exception raised when trying to pass in a Map via a mutation:

mutation isoCountryUpdate {
  isoCountryUpdate(input: {
    clientMutationId: "1234"
      isoCountry: {
          id: 2747
          codeAlpha2: "YY"
          codeAlpha3: "YYY"
          name: "TEST"
          codeNumeric: "66"
          confirmationResponses: {key: "TEST", value: "NO"}
      }
    }) {
    clientMutationId
    result {
      id
      name
    }
  }
}

Caused by: java.lang.IllegalArgumentException: Can not deserialize instance of java.util.LinkedHashMap out of START_ARRAY token
 at [Source: N/A; line: -1, column: -1] (through reference chain: p4.entities.common.IsoCountry["confirmationResponses"])
    at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3605) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:3546) ~[jackson-databind-2.8.9.jar:2.8.9]
    at io.leangen.graphql.metadata.strategy.value.jackson.JacksonValueMapper.fromInput(JacksonValueMapper.java:33) ~[spqr-0.9.3.jar:na]
    at io.leangen.graphql.metadata.strategy.value.ValueMapper.fromInput(ValueMapper.java:11) ~[spqr-0.9.3.jar:na]
    at io.leangen.graphql.generator.mapping.common.InputValueDeserializer.getArgumentValue(InputValueDeserializer.java:19) ~[spqr-0.9.3.jar:na]
    at io.leangen.graphql.execution.ResolutionEnvironment.getInputValue(ResolutionEnvironment.java:63) ~[spqr-0.9.3.jar:na]
    at io.leangen.graphql.execution.OperationExecutor.execute(OperationExecutor.java:91) ~[spqr-0.9.3.jar:na]
    at io.leangen.graphql.execution.OperationExecutor.execute(OperationExecutor.java:59) ~[spqr-0.9.3.jar:na]
    ... 129 common frames omitted
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.LinkedHashMap out of START_ARRAY token
 at [Source: N/A; line: -1, column: -1] (through reference chain: p4.entities.common.IsoCountry["confirmationResponses"])
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:270) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.DeserializationContext.reportMappingException(DeserializationContext.java:1234) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1122) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1075) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer._deserializeFromEmpty(StdDeserializer.java:892) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:358) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:27) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) ~[jackson-databind-2.8.9.jar:2.8.9]
    at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3600) ~[jackson-databind-2.8.9.jar:2.8.9]
    ... 136 common frames omitted

[brettcooper]

I believe we had the same issue and fixed it by setting:
generator.withScalarMappingStrategy(new MapScalarStrategy());

[kaqqao]

This will indeed change the way maps are treated, and will solve the immediate issue. Maps will be treated as complex scalar values (i.e. JSON blobs) and not transformed into lists of key-value pairs. But this means subselection is not possible (scalars are leaf types)...

[kaqqao]

@mjp91 @brettcooper @bpoussin
I was looking into what's needed to make Jackson deserialize maps when they're encoded as list of key-value pairs. It's doable, but quite complex. So I'm wondering if it's worth it.
In your use-cases so far, did you benefit from the current default behavior that represents maps as lists (preserving type-safety), or does the simple map-as-a-blob strategy offered by MapScalarStrategy suffice?

[mjp91]

@kaqqao we've got by treating them as scalars, would be nice to have the extra type safety and sub-selection but not a must

[brettcooper]

@kaqqao MapScalarStrategy() seems to serve our needs for the time being.

[kaqqao]

InputConverter mechanism has been completely overhauled to attach itself to the Jackson/Gson deserialization logic to properly apply the conversions throughout the object hierarchy. This unfortunately imposes limitations on TYPE_USE annotations on input fields (@GraphQLId being the only relevant example) because not a single JSON library for Java supports AnnotatedType as of yet.

Worth to note, maps are now treated as scalars by default, so the MapScalarStrategy is now deprecated.

[kvzn]

I solved the this JSON parse issue by replacing "Map<String, String> request" with "Map<String, Object> request"

@PostMapping(value = "/graphql", consumes = MediaType.APPLICATION_JSON_UTF8_VALUE, produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    @ResponseBody
    public Map<String, Object> graphql(@RequestBody Map<String, Object> request, HttpServletRequest raw) {
        ExecutionResult executionResult = graphQL.execute(ExecutionInput.newExecutionInput()
                .query(request.get("query").toString())
                .operationName(request.get("operationName") != null ? request.get("operationName").toString() : null)
                .context(raw)
                .build());
        return executionResult.toSpecification();
    }