在Ruby中使用GraphQL

在Ruby中使用GraphQL，可以使用graphql-ruby gem來實現。首先需要安裝gem：

gem 'graphql', '~> 1.9'

然后在終端運行bundle install來安裝gem。

接下來，創建GraphQL schema并定義查詢和mutation：

# app/graphql/types/query_type.rb
Types::QueryType = GraphQL::ObjectType.define do
  name "Query"

  field :all_users, !types[Types::UserType] do
    resolve -> (obj, args, ctx) { User.all }
  end
end

# app/graphql/types/mutation_type.rb
Types::MutationType = GraphQL::ObjectType.define do
  name "Mutation"

  field :create_user, Types::UserType do
    argument :name, !types.String
    argument :email, !types.String

    resolve -> (obj, args, ctx) { User.create(name: args[:name], email: args[:email]) }
  end
end

# app/graphql/types/user_type.rb
Types::UserType = GraphQL::ObjectType.define do
  name "User"

  field :id, !types.ID
  field :name, !types.String
  field :email, !types.String
end

然后創建GraphQL schema：

# app/graphql/schema.rb
Schema = GraphQL::Schema.define do
  query Types::QueryType
  mutation Types::MutationType
end

最后，將GraphQL endpoint添加到Rails應用中：

# config/routes.rb
post "/graphql", to: "graphql#execute"

創建GraphQL controller：

# app/controllers/graphql_controller.rb
class GraphqlController < ApplicationController
  def execute
    result = Schema.execute(params[:query], variables: params[:variables])
    render json: result
  end
end

現在就可以通過發送GraphQL查詢和mutation來與應用程序交互了。可以使用GraphiQL等工具來測試GraphQL端點。