Graphql-ruby: json scalar type

[huan-ji]

Is it possible to add a json scalar type to avoid having to send raw json as a string? That way in a JS web environment it won't be necessary to JSON.parse the string data.

[rmosolgo]

Yes, you can define custom scalars.

There's an example in the ScalarType docs: http://www.rubydoc.info/github/rmosolgo/graphql-ruby/GraphQL/ScalarType

and one in the spec: https://github.com/rmosolgo/graphql-ruby/blob/master/spec/graphql/scalar_type_spec.rb

How does that look?

[domkm]

@rmosolgo How do you use a custom scalar type as a mutation input field?

JsonType = GraphQL::ScalarType.define do
  name "JSON"
  coerce_input -> (x) { JSON.parse(x) }
  coerce_result -> (x) { JSON.dump(x) }
end

input_field :whatever, JsonType

The above code is causing mutation input to be wrapped in GraphQL::Query::Arguments.

[rmosolgo]

Ohh that sounds like a bug in Query::Arguments -- I think it assumes all ruby hashes are meant to represent InputObjectTypes, but now it's possible that that's not the case!

As a workaround you can call Arguments#to_h to get a plain hash version of that object.

[zamith]

I tried this on an input type argument to be used in a relay mutation, and I keep getting:

Argument '<argument-name>' on InputObject 'SomethingInput' has an invalid value

The way I'm writing the mutation is:

mutation {
   createGroupConsultation(input: {something: {argument-name: {other_thing: 2}, other_argument: 1}}) {
    result
  }
}

Arguments of other types work just fine. Hope this is clear enough, as I'm also trying to figure out want went wrong, but as far as I can tell when getting here, the value.value is #<GraphQL::Language::Nodes::InputObject:0x007fc75ba419b8 @arguments=[], @col=57, @line=2> and field.type is scalar, which makes the validation return false.

In other words, the value is being stored as an InputObject as not as a hash.

I suspect it might be the way I'm passing the objects in, but not sure.

[zamith]

I was able to fix this by sending the arguments as strings.

mutation {
   createGroupConsultation(input: {something: {argument-name: "{\"other_thing\": 2}", other_argument: 1}}) {
    result
  }
}

Is this the intended behaviour?

[rmosolgo]

Is this the intended behaviour?

Yes -- for the JsonType described above, the data must be sent as string. If the data is given as GraphQL arguments, GraphQL will try to validate them!

[chrise86]

My arguments are still getting wrapped in GraphQL::Query::Arguments. On the client I am calling JSON.stringify(object) and passing that as a param. What am I doing wrong?

[rmosolgo]

Taking a crack at fixing this here: https://github.com/rmosolgo/graphql-ruby/pull/304

After that, argument :json, JSONScalar will be a plain hash instead of a Query::Arguments

[rmosolgo]

That fix was merged into 0.19.3, please let me know if you find the argument bug again!

[bwinterling]

Just wanted to add a comment here in case it helps other folks that find their way here. Using SchemaClassName.execute(query_string) to test my schema, I was getting a parse error.

{"errors"=>[{"message"=>"Parse error on \":\" (STRING) at [1, 44]", "locations"=>[{"line"=>1, "column"=>44}]}]} or
{"errors"=>[{"message"=>"Parse error on \"super\" (STRING) at [1, 39]", "locations"=>[{"line"=>1, "column"=>39}]}]}

Don't forget to double escape the JSON string in your query string.

For example:

query_string = <<~QUERY
  mutation {
    updateForm(
      id: #{form.id},
      data: "{ \\"super\\": \\"special\\" }"
    ) { data }
  }
QUERY

result = SchemaClassName.execute(query_string)

[jturkel]

@rmosolgo - Is supporting non-string encoded custom JSON scalars totally off the table? We've hit a use case where they could be useful. graphql.js supports them via graphql-type-json so it would be consistent with the reference GraphQL implementation :)

[rmosolgo]

I'm open to it!