解析多个 json 对象并将它们保存在 Rails 4 中

Question

我有 curl 命令：

 curl -v -H "Accept: application/json" -H "Content-type: application/json" -X POST -d '{
"map":
     {"lat":"123.45543","lon":"45.43424","vibration_level":"456","time_sent":"20.05.1994" } 
}' http://localhost:3000/maps

在我的创建控制器方法中，我有：

def create
    @map = Map.new(map_params)
    respond_to do |format|
      if @map.save
        format.json {
          render :show, status: :created, location: @map
        }
      else
        format.json { render json: @map.errors, status: :unprocessable_entity }
      end
    end
  end

这个方法是脚手架的。 Rails 自动将我的 JSON 转换为哈希并将其正确保存到我的数据库中。但是，如果我有多个这样的 JSON 对象，我该如何解析 JSON：

curl -v -H "Accept: application/json" -H "Content-type: application/json" -X POST -d '{
"map":
{"lat": "51.088672", "lon": "71.396522", "vibration_level": "300", "time_sent": "07:25:00"},
{"lat": "51.088672", "lon": "71.396453", "vibration_level": "300", "time_sent": "07:25:01"},
{"lat": "51.088829", "lon": "71.396476", "vibration_level": "300", "time_sent": "07:25:14"} 
}' http://localhost:3000/maps

当我尝试该命令时，我得到一个解析错误。

编辑： maps_controller.rb

class MapsController < ApplicationController
  before_action :set_map, only: [:show, :edit, :update, :destroy]
  skip_before_filter  :verify_authenticity_token
  before_action :parse_json_data_to_params, except: [ :index,:new,:edit,:show ]

  # GET /maps
  # GET /maps.json
  def index
    @coords = Map.all
  end

  # GET /maps/1
  # GET /maps/1.json
  def show
  end

  # GET /maps/new
  def new
    @map = Map.new
  end

  # GET /maps/1/edit
  def edit
  end

  # POST /maps
  # POST /maps.json
  def create      
    @map = Map.new(map_params)
       respond_to do |format|
      if @map.save
        format.json {
          render :show, status: :created, location: @map
        }
      else
        format.json { render json: @map.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /maps/1
  # PATCH/PUT /maps/1.json
  def update
    respond_to do |format|
      if @map.update(map_params)
        format.html { redirect_to @map, notice: 'Map was successfully updated.' }
        format.json { render :show, status: :ok, location: @map }
      else
        format.html { render :edit }
        format.json { render json: @map.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /maps/1
  # DELETE /maps/1.json
  def destroy
    @map.destroy
    respond_to do |format|
      format.html { redirect_to maps_url, notice: 'Map was successfully destroyed.' }
      format.json { head :no_content }
    end
  end


  private
    # Use callbacks to share common setup or constraints between actions.
    def set_map
      @map = Map.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def map_params
      params.permit(maps: [:lat, :lon, :vibration_level, :time_sent])
    end

  def parse_json_data_to_params
    params.merge!(ActiveSupport::JSON.decode(request.raw_post))
  end

end

编辑2：

Started POST "/maps" for ::1 at 2015-06-14 20:56:57 +0600
Processing by MapsController#create as JSON
  Parameters: {"maps"=>[{"lat"=>"51.088672", "lon"=>"71.396522", "vibration_level"=>"300", "time_sent"=>"07:25:00"}, {"lat"=>"51.088672", "lon"=>"71.396453", "vibration_level"=>"300", "time_sent"=>"07:25:01"}, {"lat"=>"51.088829", "lon"=>"71.396476", "vibration_level"=>"300", "time_sent"=>"07:25:14"}], "map"=>{}}
Unpermitted parameter: map
   (0.1ms)  begin transaction
   (0.1ms)  rollback transaction
Completed 422 Unprocessable Entity in 8ms (Views: 0.2ms | ActiveRecord: 0.7ms)

Answer 1

在这种情况下，您也可以通过@maps = Map.create(map_params) 简单地创建它们，但是现在 - 您需要更改map_params 方法的定义，这是必须的。

方法如下：

def map_params
  params.permit(maps: [:lat, :lon, :vibration_level, :time_sent])
end

还有一件事：将attr_accessor: maps 添加到您的模型类中：

def Map < ActiveRecord::Base
  attr_accessor :maps
  # other code
end

编辑：

您在 JSON 末尾传递 "map"=>{}，这就是您看到错误的原因。