渲染json出現錯誤找不到控制器渲染頭no_content204的模板

我有一個控制器，它使用來自模型的資料呈現 json。當我輸入路線以獲取它時，它什么也不做，只是在控制臺中顯示和錯誤。

控制器：

    class Api::ForecastController < ApplicationController
      before_action :set_hourly_forecast, only: %i[ show edit update destroy ]
    
    
      def index
        respond_to do |format|
            format.html do
              @hourly_forecasts = HourlyForecast.where(forecast_location_id: params[:forecast_location_id]).paginate(:page => params[:page], :per_page=>24) if params[:forecast_location_id].present?
            end
            format.json do
              weather_service = WeatherService.where(name: params[:name])
              @forecast_location = ForecastLocation.where(weather_service_id: weather_service)#& municipality: @municipality.name)
              @hourly_forecasts = HourlyForecast.where(forecast_location_id: forecast_location.id ).paginate(:page => params[:page], :per_page=>24) if params[:forecast_location_id].present?
            end
        end
      end
    
      private
        # Use callbacks to share common setup or constraints between actions.
        def set_hourly_forecast
          @hourly_forecast = HourlyForecast.find(params[:id])
        end
    
        # Only allow a list of trusted parameters through.
        def hourly_forecast_params
          params.require(:hourly_forecast).permit(:forecast_location_id, :date, :temperature, :humidity, :rain, :rain_probability, :wind_speed, :wind_direction)
        end
    end

錯誤：

> Started GET "/api/forecast.json?name=dark_sky" for 127.0.0.1 at 2022-04-20 18:33:29  0200
Processing by Api::ForecastController#index as JSON
  Parameters: {"name"=>"dark_sky"}
No template found for Api::ForecastController#index, rendering head :no_content
Completed 204 No Content in 53ms (ActiveRecord: 6.2ms | Allocations: 4983)

我使用的路線

 127.0.0.1:3000/api/forecast.json?name=dark_sky

所以輸出應該是一個包含所有小時模型的 json。但它什么也不做，在控制臺上它確實得到了選擇，但跳過了模板的這個錯誤，我不明白，因為我是新來的。

如果需要更多控制器、模型或任何內容，請在評論中提問。

uj5u.com熱心網友回復：

例如，您必須有一個單獨的模板檔案來呈現 json index.json.jbuilder。

# app/views/api/forecasts/index.json.jbuilder

json.array! @hourly_forecasts do |hourly_forecast|
  json.extract! hourly_forecast, :id, :forecast_location_id, :date, :temperature, :humidity, :rain, :rain_probability, :wind_speed, :wind_direction
  json.url api_forecast_url(hourly_forecast, format: :json)
end

https://github.com/rails/jbuilder

如果不需要過多自定義渲染的json，可以在controller中行內渲染json

format.json do
  weather_service = WeatherService.where(name: params[:name])
  @forecast_location = ForecastLocation.where(weather_service_id: weather_service)#& municipality: @municipality.name)
  @hourly_forecasts = HourlyForecast.where(forecast_location_id: forecast_location.id ).paginate(:page => params[:page], :per_page=>24) if params[:forecast_location_id].present?

  render json: @hourly_forecasts
end

https://guides.rubyonrails.org/layouts_and_rendering.html#rendering-json

https://api.rubyonrails.org/classes/ActiveModel/Serializers/JSON.html

標籤：json 轨道上的红宝石 红宝石

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