Rails用水量调查控制器问题：数据存储与得分计算

Hey, I see you're working on a Rails controller for your water usage survey and running into issues with handling form data and calculating the final score. Let's walk through how to get this sorted.

Right off the bat, I notice you're trying to do calculations with symbols like :average_shower—that won't work because symbols are just parameter names, not the actual numeric values submitted via the form. We need to pull the real values from the form params, convert them to numbers, then run your calculations. Also, with 30+ variables, we should use Rails' strong parameters to keep things secure and organized.

1. Set Up Strong Parameters #

First, define a strong params method in your controller to whitelist all the survey variables. This prevents unwanted data from being saved to your database:

class WaterusagesController < ApplicationController
  def new
    @waterusage = Waterusage.new
  end

  def create
    @user = User.find(params[:user_id])
    @waterusage = @user.waterusages.build(waterusage_params)
    
    # Calculation logic will go here next
  end

  private

  def waterusage_params
    params.require(:waterusage).permit(
      :average_shower, :shower_flow_rate, :household_size,
      # Add all 30+ of your survey variables here, e.g.:
      # :toilet_flush_volume, :daily_toilet_uses, :laundry_frequency,
      # ... rest of your variables
    )
  end
end

2. Calculate the Final Score #

Now, let's pull the numeric values from your @waterusage object and run your calculations. We'll also handle potential empty values by converting them to numbers (empty strings become 0 with to_f/to_i):

def create
  @user = User.find(params[:user_id])
  @waterusage = @user.waterusages.build(waterusage_params)

  # Calculate individual components (adjust these formulas to match your needs)
  shower_total = @waterusage.average_shower.to_f * @waterusage.shower_flow_rate.to_f * @waterusage.household_size.to_i
  toilet_total = @waterusage.toilet_flush_volume.to_f * @waterusage.daily_toilet_uses.to_i * @waterusage.household_size.to_i
  laundry_total = @waterusage.laundry_load_size.to_f * @waterusage.laundry_frequency.to_i * @waterusage.washer_efficiency.to_f

  # Sum components to get final score (adjust this logic to fit your scoring system)
  @waterusage.final_score = shower_total + toilet_total + laundry_total

  # Save the record and handle success/error
  if @waterusage.save
    redirect_to @user, notice: "Water usage survey submitted successfully!"
  else
    render :new
  end
end

3. Optional (But Recommended): Move Calculations to the Model #

If your scoring logic is complex or might need to be reused later, it's better to move it to the Waterusage model. This keeps your controller clean and follows Rails' separation of concerns:

# app/models/waterusage.rb
class Waterusage < ApplicationRecord
  belongs_to :user

  # Auto-calculate score before saving the record
  before_save :calculate_final_score

  private

  def calculate_final_score
    # Same calculation logic as before, but using the model's own attributes
    shower_total = average_shower.to_f * shower_flow_rate.to_f * household_size.to_i
    toilet_total = toilet_flush_volume.to_f * daily_toilet_uses.to_i * household_size.to_i
    laundry_total = laundry_load_size.to_f * laundry_frequency.to_i * washer_efficiency.to_f

    self.final_score = shower_total + toilet_total + laundry_total
  end
end

With this change, your controller's create method simplifies to:

def create
  @user = User.find(params[:user_id])
  @waterusage = @user.waterusages.build(waterusage_params)

  if @waterusage.save
    redirect_to @user, notice: "Water usage survey submitted successfully!"
  else
    render :new
  end
end

• Database Column: Make sure your waterusages table has a final_score column (use a decimal or float type). If not, generate a migration:

  rails generate migration AddFinalScoreToWaterusages final_score:decimal
  rails db:migrate
  

• Validations: Add model validations to ensure required fields are filled out and are numeric:

  # In waterusage.rb
  validates :average_shower, :shower_flow_rate, :household_size, presence: true, numericality: true
  

• Empty Values: Using to_f and to_i ensures empty form fields don't break your calculations (they'll be treated as 0).

内容的提问来源于stack exchange，提问作者ezweizig