Rails 4 How to get id from another controller in form

Question

We have a form to create appointments with a branch, this form needs to save the id of the current user and the id of the branch that the appointment is with. However, we can't figure out how to get the branch_id to be saved.

visits_controller.rb:

class VisitsController < ApplicationController
  before_filter :authenticate_user!, except: [ :new]
  before_action :set_visit, only: [:show, :edit, :update, :destroy]

  # GET /visits
  # GET /visits.json
  def index
    @visits = Visit.all
    @visits_by_date = @visits.group_by(&:date_from)
    @date = params[:date] ? Date.parse(params[:date]) : Date.today
    @users = User.all

  end

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

  # GET /visits/new
  def new
    @visit = Visit.new
    @branch = Branch.all


    end

  # GET /visits/1/edit
  def edit
  end

     # POST /visits
     # POST /visits.json
      def create
    @visit = Visit.new(visit_params)
    @visit.branch_id = Branch.where(:id => params[:branch_id])
    @visit.user_id = current_user.id if current_user
    respond_to do |format|
      if @visit.save
       format.html { redirect_to @visit, notice: 'Visit was successfully created.' }
      format.json { render :show, status: :created, location: @visit }
  else
       format.html { render :new }
       format.json { render json: @visit.errors, status: :unprocessable_entity }
      end
    end
  end




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

  # DELETE /visits/1
  # DELETE /visits/1.json
   def destroy
    @visit.destroy
    respond_to do |format|
       format.html { redirect_to visits_url, notice: 'Visit was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

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

    # Never trust parameters from the scary internet, only allow the white list through.
    def visit_params
      params.require(:visit).permit(:location, :date_from, :time_from, :date_to, :time_to, :comment, :branch_id, :user_id)
    end
  end

visit.rb:

class Visit < ActiveRecord::Base
    belongs_to :branch  
    belongs_to :user #:as => 'created_by' 
    validates_uniqueness_of :time_from, :scope => [:date_from, :location], :message=>"slot is already taken on selected date"

end  

new.html.erb:

<h1>New Visit</h1>

<%= render 'form' %>

<%= link_to 'Back', visits_path %>

_form.html.erb:

<% if user_signed_in? && current_user.user_type == 'client' %>


<%= form_for @visit do |f| %>
  <% if @visit.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@visit.errors.count, "error") %> prohibited this visit from being saved:</h2>

      <ul>
      <% @visit.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>


  <div class="field">
    <%= f.label :location, "Please Pick Service Provider/Branch you would like to visit:" %><br>
    <%= f.collection_select(:location, Branch.all, :branch_name, :branch_name_select, {prompt: "Select the Branch/Service"}, {:required => true}) %>
  </div>
  <div class="field">
     <%= f.label :date_from, "Please Pick Visit Date From:" %><br>
     <%= f.text_field :date_from, :required => true %>
  </div>
  <div class="field">
    <%= f.label :time_from, "Please Pick Visit Start Time:" %><br>
    <%= f.time_select :time_from, {:start_hour => 9, :end_hour => 20, :minute_step => 15,  :ampm => true}, :required => true %>
   </div>
  <div class="field">
    <%= f.label :date_to, "Please Pick Visit Date From:" %><br>
    <%= f.text_field :date_to %>
   </div>
  <div class="field">
    <%= f.label :time_to, "Please Pick Visit End Time:" %><br>
    <%= f.time_select :time_to, {:start_hour => 9, :end_hour => 20, :minute_step => 15, :ampm => true} %>
  </div>
   <div class="field">
    <%= f.label :comment, "If you have any specific requirements for your visit please let us now and leave the comment below:" %><br>
    <%= f.text_area :comment %>
  </div>

  <div class="field">
    <%= f.label :branch_id %><br>
    <%= f.hidden_field :branch_id %>
   </div>

  <div class="field">
    <%= f.label :user_id %><br>
    <%= f.hidden_field :user_id, :value => current_user.id %>
   </div>

   <div class="actions">
    <%= f.submit "Submit Visit Request"%>
   </div>
<% end %>

 <% end %>

Answer 1

Forget about "other controllers". You send some values through in params and use those values to make your @visit object. All you need in your controller's create action is this:

@visit = current_user.visits.new(visit_params)
if @visit.save
...etc

All the data you're going to use to build the @visit object can come through in params. If you want to set the branch_id, just make sure that params[:visit][:branch_id] is set to the right value, from your form.