rails jbuilder正在获取nil的Called id

Question

我正在尝试使用jbuilder gem来格式化json输出。

控制器

class LocationsController < ApplicationController
def tree
  @locations = Location.all
end

tree.json.jbuilder

Jbuilder.encode do |json|
  json.id @location.id
  json.name @location.name
end

使用url:进行测试

http://localhost:5000/locations/tree.json

结果：

Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id
Extracted source (around line #2):
1: Jbuilder.encode do |json|
2:   json.id @location.id
3:   json.name @location.name
4: end

Answer 1

您在发布的代码中似乎没有定义@location
您应该迭代您的位置，jbuilder允许您这样做，例如：

Jbuilder.encode do |json|
  json.locations @locations do |location|
    json.id location.id
    json.name location.name
  end
end

如果您想要一个平面数组，请参阅文档。