pass in and save params

app/controllers/templates_form_preview_controller.rb

@@ -11,6 +11,7 @@ class TemplatesFormPreviewController < ApplicationController
   load_and_authorize_resource :template
 
   def show
+    save_params
     @submitter = Submitter.new(uuid: params[:uuid] || @template.submitters.first['uuid'],
                                account: current_account,
                                submission: @template.submissions.new(template_submitters: @template.submitters,
@@ -22,7 +23,27 @@ class TemplatesFormPreviewController < ApplicationController
 
     @attachments_index = ActiveStorage::Attachment.where(record: @submitter.submission.submitters, name: :attachments)
                                                   .preload(:blob).index_by(&:uuid)
-
+  
     @form_configs = Submitters::FormConfigs.call(@submitter)
   end
+
+  private
+
+  def save_params
+    permitted = preview_params
+    @auth_token ||= permitted[:auth_token] || session[:auth_token]
+    @task_preview_mode ||= permitted[:task_preview_mode]
+    @accessible_partnership_ids ||= permitted[:accessible_partnership_ids]
+    @external_account_id ||= permitted[:external_account_id]
+  end
+
+  def preview_params
+    params.permit(
+      :uuid,
+      :auth_token,
+      :external_account_id,
+      :task_preview_mode,
+      accessible_partnership_ids: []
+    )
+  end
 end

app/views/templates_form_preview/show.html.erb

@@ -3,11 +3,15 @@
     <div class="flex items-center" style="flex-shrink: 0">
       <% if @template.submitters.size > 1 %>
           <form action="<%= template_form_path(@template) %>" method="get" class="mr-3">
-          <% if (auth_token = params[:auth_token] || session[:auth_token]) %>
-            <%= hidden_field_tag :auth_token, auth_token %>
+          <% if @auth_token %>
+            <%= hidden_field_tag :auth_token, @auth_token %>
           <% end %>
-          <% if params[:task_preview_mode].present? %>
-            <%= hidden_field_tag :task_preview_mode, params[:task_preview_mode] %>
+          <% if @task_preview_mode %>
+            <%= hidden_field_tag :task_preview_mode, @task_preview_mode %>
+            <%= hidden_field_tag :external_account_id, @external_account_id %>
+            <% Array(@accessible_partnership_ids).each do |id| %>
+              <%= hidden_field_tag "accessible_partnership_ids[]", id %>
+            <% end %>
           <% end %>
           <span class="font-bold mr-2"><%= t('preview_label') %></span>
           <select onchange="this.form.submit()" name="uuid" class="select base-input text-center font-normal" style="width: 180px; flex-shrink: 0;">