GraphQL::Client::DynamicQueryError Expected definition to be assigned to a static constant

Question

How to make proper ShopifyAPI::GraphQL method in Rails.

Trying the below code in rails console works fine. But when I tried to put that code and make a method in Rails controller/model, i'm getting:

GraphQL::Client::DynamicQueryError Expected definition to be assigned to a static constant

shopify_client
client = ShopifyAPI::GraphQL.new

SHOP_NAME_QUERY = client.parse <<-'GRAPHQL'
 {
  shop {
   name
  }
 }
GRAPHQL

result = client.query(SHOP_NAME_QUERY)

I tried to play around with variables following https://github.com/github/graphql-client/blob/master/guides/dynamic-query-error.md but no success.

How to make a method using the above function that will not return the mentioned error above.

Sample Model method:

def trial
  shopify_client
  client = ShopifyAPI::GraphQL.new
  shop_query = client.parse <<-'GRAPHQL'
    {
     shop {
      name
     }
    }
  GRAPHQL

  client.query(shop_query)
end

In Gemfile: gem 'shopify_api', git: 'https://github.com/Shopify/shopify_api', branch: 'graphql-support'

Answer 1

I had a similar issue a few days ago, I had to use const_set for setting the constant dynamically. So, using your example that would translate to

class Foo
  def trial
   #code to initialize shopify session here 
   set_query
   client.query(ProductQuery)
  end

  private 

  def set_query 
     query = <<-GRAPHQL
        {
          shop {
          name
        }
      }
    GRAPHQL
    Kernel.const_set(:ProductQuery, client.parse(query))
  end

  def client
    ShopifyAPI::GraphQL.new
  end
end

Shopify's GraphQL feature relies on the Github GraphQL ruby client, which mandates query be defined in a constant. Also, the shopify_api gem mandates the existence of a Shopify session before you can use this method, depending on your setup you may not have a session defined if the constant is on the class body as that get executed first by the ruby interpreter. The way around this is to set the constant dynamically