为什么在初始化外观类时在Rails控制器中出现名称错误？

Question

I'm creating a simple Rails app that consumes the Open Weather Map API and returns various weather parameters. My API call is handled in a service class and I'm trying to follow the facade pattern and deal with the parameter data in a PORO. The code I have already is below. I am getting a NameError. undefined local variable or method NameError. undefined local variable or method city'` Any idea where I am going wrong?

app/services/open_weather_api.rb

class OpenWeatherApi
  include HTTParty
  base_uri "http://api.openweathermap.org"

  def initialize(city, appid)
    @options = { query: { q: city, APPID: appid } }
  end

  def my_location_forecast
    self.class.get("/data/2.5/weather", @options)
  end
end

app/facades/forecasts_facade.rb

class ForecastsFacade
  TOKEN = Rails.application.credentials.openweather_key

  def initialize(city, forecast, temperature, weather_code, description, wind, humidity)
    @city = city
    @forecast = forecast
    @temperature = temperature
    @weather_code = weather_code
    @description = description
    @wind = wind
    @humidity = humidity
  end

  def city
    @city = params[:q]
  end

  def forecast
    if @city.nil?
      @forecast = {}
    else
      @forecast = OpenWeatherApi.new(@city, TOKEN).my_location_forecast
    end
  end

  def temperature
    @temperature = @forecast.dig('main', 'temp').to_i - 273
  end

  def weather_code
    @weather_code = @forecast.dig('weather', 0, 'id').to_i
  end

  def description
    @description = @forecast.dig('weather', 0, 'description')
  end

  def wind
    @wind = @forecast.dig('wind', 'speed').to_i
  end

  def humidity
    @humidity = @forecast.dig('main', 'humidity')
  end
end

forecasts_controller.rb

class ForecastsController < ApplicationController
  def current_weather
    @forecasts_facade = ForecastsFacade.new(city, forecast, temperature, weather_code, description, wind, humidity)
  end
end

current_weather.html.erb

<div class="page-wrapper">
  <h1 class="title">The weather in GIFs</h1>

  <div class="search">
    <%= form_tag(current_weather_forecasts_path, method: :get) do %>
      <%= text_field_tag :q, nil, placeholder: "Enter a city", class: "search-field" %>
      <%= button_tag type: 'submit', class: "search-button" do %>
        <i class="fas fa-search"></i>
      <% end %>
    <% end %>
  </div>

  <% if ForecastsFacade.forecast.dig('cod').to_i == 404 %>
    <p>Please use a valid city name!</p>
  <% elsif ForecastsFacade.forecast.dig('cod').to_i == 400 %>
    <p>Please type in a city name!</p>
  <% elsif ForecastsFacade.forecast == {} %>
  <% else %>
    <p class="weather-description"><%= "#{ForecastsFacade.city.capitalize}: #{ForecastsFacade.description}" %></p>
    <div class="gif-container"><%= image_tag(find_gif_url, class: "gif") %>
      <span class="temperature weather-attribute"><%= "#{ForecastsFacade.temperature}°C" %></span>
      <span class="wind weather-attribute"><%= "wind:#{(ForecastsFacade.wind * 3.6).to_i}km/h" %></span> <!-- converts to km/hr -->
      <span class="humidity weather-attribute"><%= "humidity:#{ForecastsFacade.humidity}%" %></span>
    </div>
  <% end %>
</div>

Answer 1

From your code what I can see is that on the page current_weather.html.erb . You have written:

<% if ForecastsFacade.forecast.dig('cod').to_i == 404 %>
    <p>Please use a valid city name!</p>
  <% elsif ForecastsFacade.forecast.dig('cod').to_i == 400 %>
    <p>Please type in a city name!</p>
  <% elsif ForecastsFacade.forecast == {} %>
  <% else %>
    <p class="weather-description"><%= "#{ForecastsFacade.city.capitalize}: #{ForecastsFacade.description}" %></p>
    <div class="gif-container"><%= image_tag(find_gif_url, class: "gif") %>
      <span class="temperature weather-attribute"><%= "#{ForecastsFacade.temperature}°C" %></span>
      <span class="wind weather-attribute"><%= "wind:#{(ForecastsFacade.wind * 3.6).to_i}km/h" %></span> <!-- converts to km/hr -->
      <span class="humidity weather-attribute"><%= "humidity:#{ForecastsFacade.humidity}%" %></span>
    </div>
  <% end %>

Here ForecastsFacade is a class. forecast is an instance method. So, initialized is not called when you're calling the function.

Try to use ajax request and use @forecasts_facade in the js.erb to create a partial which will help you in achieving the functionality.