(How) Can I use the form object for editing / updating procedures?

Question

Failed to refrain from restarting RailsForum and cross-asked this question.

I have the following form object (in Rails 4)

class StationForm include Virtus include ActiveModel::Model # I think this is unnecessary # extend ActiveModel::Naming # include ActiveModel::Conversion # include ActiveModel::Validations # Station attr_reader :station attribute :station_name, String attribute :station_description, String # Address attr_reader :address attribute :address_url, String attribute :address_priority, Integer attribute :address_is_active, Boolean def persisted? false end def save if valid? persist true else false end end private def persist @station = Station.create(name: station_name, description: station_description) @address = @station.addresses.create(url: address_url, priority: address_priority, is_active: address_is_active) end end 

I can use this form object in my new / created methods

 class StationsController < ApplicationController def new @station_form = StationForm.new end def create @station_form = StationForm.new(station_form_params) @station_form.save redirect_to station_path(@station) end private def station_form_params params.require(:station_form).permit(:station_name, :station_description, :address_url, :address_priority, :address_is_active) end end 

However, I am unable to use it for editing / updating procedures ...

Is it possible to use the form object for editing / updating, and if so, how to do it?

Answer 1

You will need to use the "initialize" method in the StationForm object to use it for editing. if you pass id, it will assume that the object already exists, and from there we can consider it as an object with conservation. Also add the "update" method to update the attributes of the object.

 class StationForm include Virtus.model include ActiveModel::Model # I think this is unnecessary # extend ActiveModel::Naming # include ActiveModel::Conversion # include ActiveModel::Validations attr_reader :station attribute :station_name, String attribute :station_description, String attr_reader :address attribute :address_url, String attribute :address_priority, Integer attribute :address_is_active, Boolean def initialize(attr = {}) if !attr["id"].nil? @station = Station.find(attr["id"]) @address = @station.addresses.first self[:station_name] = attr[:station_name].nil? ? @station.name : attr[:station_name] self[:station_description] = attr[:station_description].nil? ? @station.description : attr[:station_description] self[:address_url] = attr[:address_url].nil? ? @address.url : attr[:address_url] self[:address_priority] = attr[:address_priority].nil? ? @address.priority : attr[:address_priority] self[:address_is_active] = attr[:address_is_active].nil? ? @address.is_active : attr[:address_is_active] else super(attr) end end def persisted? @station.nil? ? false : @station.persisted? end def id @station.nil? ? nil : @station.id end def save if valid? persist true else false end end def update if valid? update_form true else false end end private def persist @station = Station.create(name: station_name, description: station_description) @address = @station.addresses.create(url: address_url, priority: address_priority, is_active: address_is_active) end def update_form @station.update_attributes( :name => self[:station_name], :description => self[:station_description] ) @address.update_attributes( :url => self[:address_url], :priority => self[:address_priority], :is_active=> self[:address_is_active] ) end end 

And the controller will be like

 def new @station = StationForm.new end def edit @station = StationForm.new("id" => params[:id]) end def create @station = StationForm.new(station_params) respond_to do |format| if @station.save format.html { redirect_to stations_path, notice: 'Station was successfully created.' } format.json { render :show, status: :created, location: @station } else format.html { render :new } format.json { render json: @station.errors, status: :unprocessable_entity } end end end def update @station = StationForm.new(station_params.merge("id" => params[:id])) respond_to do |format| if @station.update format.html { redirect_to stations_path, notice: 'Station was successfully updated.' } format.json { render :show, status: :ok, location: @station } else format.html { render :edit } format.json { render json: @station.errors, status: :unprocessable_entity } end end end 

use the "persisted" and "id" method from StationForm in the _form.html.erb file

  <%= form_for(@station, :url => @station.persisted? ? station_path(@station.id) : stations_path, :method => @station.persisted? ? "put": "post") do |f| %> <% if @station.errors.any? %> <div id="error_explanation"> <h2><%= pluralize(@station.errors.count, "error") %> prohibited this station from being saved:</h2> <ul> <% @station.errors.full_messages.each do |message| %> <li><%= message %></li> <% end %> </ul> </div> <% end %> <div class="field"> <%= f.label :station_name %><br> <%= f.text_field :station_name %> </div> <div class="field"> <%= f.label :station_description %><br> <%= f.text_field :station_description %> </div> <div class="field"> <%= f.label :address_url%><br> <%= f.text_field :address_url %> </div> <div class="field"> <%= f.label :address_priority%><br> <%= f.text_field :address_priority%> </div> <div class="field"> <%= f.label :address_is_active %><br> <%= f.text_field :address_is_active %> </div> <div class="actions"> <%= f.submit %> </div> <% end %>