Ruby GraphQL: How to order arguments in an option?

Question

I am using SearchObject with GraphQL in Ruby on Rails and created an option called :order_by

option :order_by, type: LinksOrderBy, with: :apply_order_by

The type LinksOrderBy is defined by this:

class LinksOrderBy < ::Types::BaseInputObject
  argument :created_at, AscDescEnum, required: false
  argument :description, AscDescEnum, required: false
  argument :id, AscDescEnum, required: false
  argument :updated_at, AscDescEnum, required: false
  argument :url, AscDescEnum, required: false
end

But when I try something like this in GraphQL query:

{allLinks(order_by:{id: asc, description: desc}) {
    id
    description
}}

I don't get it in the right order:

def apply_order_by(scope, value)
  scope.order(value.arguments.to_h.map{|k, v| k + ' ' + v}.join(', ')) # "description desc, id asc"
end

As you can see the right order should be "id, description", not "description, id".

score 3 · Accepted Answer · answered Oct 30 '19 at 20:08

The ruby Hash instances are not ordered (see Is order of a Ruby hash literal guaranteed?)

To leverage the optional multi sorting options in GraphQL input types, I usually use the following structure:

1 enum to contain all filterable/sortable/searchable field of a resource (ex: UserField)
1 enum to contain the 2 sort directions (asc and desc)
1 field accepting an optional list of { field: UserField!, sortDir: SortDir! } inputs.

This then enables the API consumers to simply do queries like:

allUsers(sort_by: [{field: username, sortDir: desc}, {field: id, sortDir: asc}]) {
  # ...
}

And this pattern can be easily re-used for searching and filtering:

allUsers(search: [{field: username, comparator: like, value: 'bob'}]) {}
allUsers(search: [{field: age, comparator: greater_than, value: '22'}]) {} # type casting is done server-side
allUsers(search: [{field: username, comparator: equal, value: 'bob'}]) {} # equivalent of filtering

Eventually, with further deeper work you can allow complex and/or for the input:

allUsers(
  search: [
    {
      left: {field: username, comparator: like, value: 'bob'}
      operator: and
      right: {field: dateOfBirth, comparator: geater_than, value: '2001-01-01'}
    }
  ]
)

Disclaimer: the last example above is one of the many things I want to implement in my GQL API but I haven't had the time to think it through yet, it's just a draft

I used your approach to create a gem. gem 'graphql_scaffold'. What do you think about it? — Arthur Felipe, Nov 22 '19 at 14:54
That's a good idea, let me know if you need help implementing it @ArthurFelipe — MrYoshiji, Nov 25 '19 at 03:53
Fell free to fork and add anything you think would be better. It is still at the begining... Thank you! https://github.com/arthurmolina/graphql_scaffold — Arthur Felipe, Nov 26 '19 at 11:17
I'm totally new to graphql, could you share a demo/github link to understand how u extended the GraphQL-Ruby Type Definition System and in which file you added the field to all queries? — Yannick Schröder, Jun 07 '20 at 21:23

Ruby GraphQL: How to order arguments in an option?

1 Answers1