Rails 4：将局部变量从包含 form_for 帮助器的部分传递给 js.erb 文件

Question

如何将局部变量从 form_for 助手传递到 js 文件？

我有以下名为 _subscribe.html.erb 的文件

<%= form_for @subscription, :url => {:controller => "subscriptions", :action => "create"} do |f| %>
  <div><%= hidden_field_tag :group_id, group.id %></div>
  <%= f.submit "Subscribe", class: "btn btn-primary subscribe_btn" %>
<% end %>

group 局部变量从 do 块传递到此表单并可以工作（到目前为止仅 html）。我想把它变成一个 ajax 调用，所以我在表单中添加了 remote: true 并将文件 create.js.erb 添加到订阅文件夹中：

$("#new_subscription").html("<%= escape_javascript(render('subscriptions/unsubscribe', locals: { group: group } )) %>")

这是我的订阅控制器创建操作：

def create
    @subscription = current_user.subscriptions.create(:group_id => params[:group_id])
    @subscription.save
      respond_to do |format|
      format.html { redirect_to groups_path, flash[:success] = "You have successfully subscribed to this group" }
      format.js  
    end
  end

但是现在我得到了这个错误：

ActionView::Template::Error (undefined local variable or method `group' for #<#<Class:0x007fe7ecfd4950>:0x007fe7ecfde7e8>):
    1: $("#new_subscription").html("<%= escape_javascript(render('subscriptions/unsubscribe', locals: { group: group } )) %>")
  app/views/subscriptions/create.js.erb:1:in `_app_views_subscriptions_create_js_erb__3184685282411376061_70317032458920'
  app/controllers/subscriptions_controller.rb:8:in `create'

提交时未将组局部变量从 form_for 传递到 create.js.erb。在过去的 4 个小时里，我已经尝试了所有方法，但仍然不够用。如何解决此问题并将局部变量从 _subscribe.html.erb 部分传递给 create.js.erb 文件？

编辑：

更多代码...首先我的订阅控制器创建操作：

def create
    @group = Group.find(params[:group_id])
    @subscription = current_user.subscriptions.create(:group_id => @group.id)
    @subscription.save
    respond_to do |format|
      format.html { redirect_to groups_path }
      format.js 
    end
  end

并销毁操作：

def destroy
    @group = Group.find(params[:id])
    @subscription = current_user.subscriptions.find_by(group_id: @group.id)
    @subscription.destroy
    respond_to do |format|
      format.html { redirect_to groups_path }
      format.js
    end
   end

& 创建.js.erb

$("#subscribe_button").html("<%= escape_javascript(render('subscriptions/unsubscribe', locals: { group: @group } )) %>")

&destory.js.erb

$("#unsubscribe_button").html("<%= escape_javascript(render('subscriptions/subscribe', locals: { group: @group } )) %>")

我仍然在日志中收到以下错误：

Started POST "/subscriptions" for 127.0.0.1 at 2014-11-20 22:23:39 +0000
Processing by SubscriptionsController#create as JS
  Parameters: {"utf8"=>"✓", "group_id"=>"1", "commit"=>"Subscribe"}
  User Load (0.9ms)  SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'b0afd34150d0c021a1e4d0dfa357107a2aa59f00' LIMIT 1
  Group Load (0.4ms)  SELECT "groups".* FROM "groups" WHERE "groups"."id" = $1 LIMIT 1  [["id", "1"]]
   (0.2ms)  BEGIN
  Subscription Exists (0.6ms)  SELECT 1 AS one FROM "subscriptions" WHERE ("subscriptions"."group_id" = 1 AND "subscriptions"."user_id" = 2) LIMIT 1
  SQL (0.6ms)  INSERT INTO "subscriptions" ("created_at", "group_id", "role", "updated_at", "user_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["created_at", Thu, 20 Nov 2014 22:23:39 UTC +00:00], ["group_id", 1], ["role", "pending"], ["updated_at", Thu, 20 Nov 2014 22:23:39 UTC +00:00], ["user_id", 2]]
   (0.4ms)  COMMIT
   (0.1ms)  BEGIN
  Subscription Exists (0.7ms)  SELECT 1 AS one FROM "subscriptions" WHERE ("subscriptions"."group_id" = 1 AND "subscriptions"."id" != 96 AND "subscriptions"."user_id" = 2) LIMIT 1
   (0.2ms)  COMMIT
  Rendered subscriptions/_unsubscribe.html.erb (100.3ms)
  Rendered subscriptions/create.js.erb (101.7ms)
Completed 500 Internal Server Error in 120ms

ActionView::Template::Error (undefined local variable or method `group' for #<#<Class:0x007fdc05a244a8>:0x007fdc0545b350>):
    1: <%= debug group %>
    2: <div id="unsubscribe_button"> 
    3: <%= button_to "Unsubscribe", subscription_path(group), :remote => true, :method => 'delete', class:  "btn subscribe_btn" %>
    4: </div>
  app/views/subscriptions/_unsubscribe.html.erb:1:in `_app_views_subscriptions__unsubscribe_html_erb__4479900334468069300_70291478478720'
  app/views/subscriptions/create.js.erb:1:in `_app_views_subscriptions_create_js_erb__1667797080065562395_70291478425360'
  app/controllers/subscriptions_controller.rb:8:in `create'

您可以清楚地看到在创建操作中设置了@group，并且正在成功创建订阅，但未在 js.erb 文件中设置局部变量。

Answer 1

问题是当您在create 操作中时，您没有在上一个操作中设置的变量。

所以您需要再次设置@group 实例变量，然后在您的create.js.erb 模板中使用它。

def create
  @group = Group.find(params[:group_id])
  @subscription = current_user.subscriptions.create(:group_id => @group.id)
  @subscription.save
  respond_to do |format|
    format.html { redirect_to groups_path, flash[:success] = "You have successfully subscribed to this group" }
    format.js
  end
end

$("#new_subscription").html("<%= escape_javascript(render('subscriptions/unsubscribe', locals: { group: @group } )) %>")

Answer 2

你没有。当前请求结束时，即呈现表单时，执行结束。 .js.erb 视图模板在表单提交之前不会被调用，开始一个新的请求。

您必须创建一个实例变量，例如@group = however_you_get_the_group 在控制器的创建操作中使其对 .js.erb 视图可见，并引用如下：locals: { group: @group }