A simple GraphQL wrapper around Faraday.

simple_graphql_wrapper.rb

require 'faraday'
require 'json'

class GraphQLClient
  class << self
    attr_accessor :base_site, :base_headers

    def base_headers
      @base_headers ||= {
          'Content-Type' => 'application/json',
          'Accept' => 'application/json'
      }
    end
  end

  attr_accessor :site, :headers, :body, :response

  def initialize(**args)
    @site = args[:endpoint] || args[:site] || base_site
    headers.merge!(args[:headers].to_h)
    self
  end

  def query(**args)
    self.body = {}
    body["query"] = args[:query] || raise(ArgumentError 'Missing query string.')
    body["variables"] = args[:variables]
    body["operationName"] = args[:operation_name]

    self.response = post
  end

  def headers
    @headers ||= base_headers.to_h
  end

  private

  def base_site
    self.class.base_site
  end

  def base_headers
    self.class.base_headers
  end

  def faraday_module
    Faraday
  end

  def json_parser
    JSON
  end

  def new_faraday_connection
    faraday_module.new
  end

  def body_json
    json_parser.generate(body)
  end

  def post
    new_faraday_connection.post do |req|
      req.url site
      req.headers.merge! headers
      req.body = body_json
    end
  end
end