Variables sent by client are not taken into account

I'm sending a POST request with a JSON object attached that contains the query and variables. But I get an error that the variable is not defined.

I'm using Flask-GraphQL==1.4.1

app.add_url_rule('/graphql', view_func=orm.db_session(GraphQLView.as_view('graphql', schema=schema, graphiql=True)))

This may not be related to Flask-GraphQL at all. I've updated to the master branch where it uses graphql_server and I still have the same problem. I asked at SO: https://stackoverflow.com/questions/50814621/python-graphql-variable-not-defined

On a side-note, maybe it is partially a problem with Flask-GraphQL in version 1.4.1, because the "Variable X is not defined" comes from the validation step

flask-graphql/flask_graphql/graphqlview.py

Lines 192 to 197 in 724695a

    
           validation_errors = validate(self.schema, ast) 
        
           if validation_errors: 
        
               return ExecutionResult( 
        
                   errors=validation_errors, 
        
                   invalid=True, 
        
               )

And the variables are not being made known to the validate() function in any way.

	validation_errors = validate(self.schema, ast)
	if validation_errors:
	return ExecutionResult(
	errors=validation_errors,
	invalid=True,
	)