帶有多個可選參數的Rails Active Record查詢

Question

在Rails 4.1應用程序控制器中創建ActiveRecord查詢的最佳方式是什么，它可以使用0到4個可選查詢參數，如果沒有，我必須返回所有項目：-

i) GET /tasks -> returns all tasks

ii) GET /tasks?created=10347892 -> return tasks created after params[:created] timestamp

iii) GET /tasks?nearTo=0,0 -> return tasks near to 3 kms of params[:nearTo] geocoordinate

iv) GET range=range1 -> return tasks with range like 'range1' 

v) of course we need to support the following query GET /tasks?created=1034589&nearTo=0,0&range=range1

任何幫助表示贊賞。

Answer 1

在模型上創建范圍，然后在模型上使用類方法以基於傳遞的參數進行過濾。

在任務模型上創建范圍-一些示例：

scope :created_after, -> (time) { where("tasks.created_at > ?", time) }
scope :created_between, -> (start_time, end_time) { where("tasks.created_at >= ? AND tasks. created_at <= ?", start_time, end_time) }
scope :near_to, -> (x, y, miles) { near([x, y], miles) }
scope :range_like, -> (query) { where("tasks.range LIKE ?", query) }
scope :with_users, -> (user_ids) { where(tasks: {user_id: user_ids}) }
...
etc

在Task模型上創建類方法以應用范圍-如果不存在參數，則返回所有任務

def self.filter(params)
  tasks = Task.all
  tasks = tasks.created_after(params[:created]) if params[:created].present?
  ...
  ...
  tasks = tasks.range_like(params[:range])      if params[:range].present?
  tasks = tasks.with_users(params[:user_ids])   if params[:user_ids].present?
  return tasks
end

然后可以從控制器中調用

@tasks = Task.filter(params)