如何仅在 returns > 0 时显示 link_to 助手

Question

我有这个帮手link

link_to "", product_path(product, anchor: "disqus_thread"), data: { "disqus-identifier" => "#{url_for([product, {only_path: false}])}" }, class: "no-underline bold grey-text text-darken-3 margin-left"

布局：application.rb

%script{id: "dsq-count-scr", src: "https://url.disqus.com/count.js", async: "async"}

_disqus.html.erb

<div class="col-lg-8 col-lg-offset-2 big-top-space margin-bottom">
  <div id="disqus_thread"></div>
  <script>
    var disqus_shortname = 'yourname';
    var disqus_identifier = '<%= url_for([product, {only_path: false}]) %>';
    var disqus_title = '<%= product.name %>';
    var disqus_url = '<%= url_for([product, {only_path: false}]) %>';
  (function() { // DON'T EDIT BELOW THIS LINE
     var d = document, s = d.createElement('script');
     s.src = 'https://url.disqus.com/embed.js';
     s.setAttribute('data-timestamp', +new Date());
     (d.head || d.body).appendChild(s);
  })();
</script>
<noscript>Please enable JavaScript to view the <a href="https://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>

</div>

并且一切正常我得到一个数字，这个数字是我索引视图中每个 post 的 disqus 评论计数器，但是如果 大于 0，如何只显示该数字？ 如果 等于 0 我不想在视图中显示它。有人知道如何解决这个问题吗？非常感谢

我试过这个：

add this column to products comment_count :integer

我改变了我的 _disqus.html

 <div class="col-lg-8 col-lg-offset-2 big-top-space margin-bottom">
      <div id="disqus_thread"></div>
      <script>
        var disqus_shortname = 'yourname';
        var disqus_identifier = '<%= url_for([product, {only_path: false}]) %>';
        var disqus_title = '<%= product.name %>';
        var disqus_url = '<%= url_for([product, {only_path: false}]) %>';

       var disqus_config = function () {
    this.callbacks.onNewComment = [
      function() {        
        $.ajax({
          method: "PATCH",
          url: '<%= product_path(product) %>',
          data: {increment: "comment_count"}
        })
      }
    ];
};
      (function() { // DON'T EDIT BELOW THIS LINE
         var d = document, s = d.createElement('script');
         s.src = 'https://url.disqus.com/embed.js';
         s.setAttribute('data-timestamp', +new Date());
         (d.head || d.body).appendChild(s);
      })();
    </script>
    <noscript>Please enable JavaScript to view the <a href="https://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>

    </div>

Product_controller

def update    
    product = Product.find(params[:id])
    product.update(update_product)
  end
def update_product
  params.permit(:comment_count)
end

来源：https://help.disqus.com/customer/portal/articles/466258-capturing-disqus-commenting-activity-via-callbacks

但是我得到这个错误

   Started PATCH "/products/12" for ::1 at 2017-04-12 17:44:38 -0500
Processing by ProductsController#update as */*
Parameters: {"increment"=>"comment_count", "id"=>"12"}
ShoppingCart Load (0.0ms) SELECT "shopping_carts".* FROM "shopping_carts" WH
ERE "shopping_carts"."id" = ? LIMIT 1 [["id", 102]]
Product Load (0.0ms) SELECT "products".* FROM "products" WHERE "products"."i
d" = ? LIMIT 1 [["id", 12]]
CACHE (0.0ms) SELECT "products".* FROM "products" WHERE "products"."id" = ?
LIMIT 1 [["id", "12"]]
Unpermitted parameters: increment, id
(0.0ms) begin transaction
User Load (0.0ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT
1 [["id", 1]]
(0.0ms) commit transaction
Rendered products/update.haml within layouts/application (0.0ms)
(0.0ms) SELECT COUNT(*) FROM "products" INNER JOIN "in_shopping_carts" ON "p
roducts"."id" = "in_shopping_carts"."product_id" WHERE "in_shopping_carts"."shop
ping_cart_id" = ? [["shopping_cart_id", 102]]
Rendered partials/_unlogged.haml (15.5ms)
Rendered partials/_nav.haml (765.8ms)
Completed 200 OK in 3476ms (Views: 3448.8ms | ActiveRecord: 0.0ms)

Unpermitted parameters: increment, id

在控制台中

comment_count: nil

有人可以帮助我吗？

Answer 1

你不能 - 至少不能以你尝试的方式。

link_to "", product_path(product, anchor: "disqus_thread"), data: { "disqus-identifier" => "#{url_for([product, {only_path: false}])}" }, class: "no-underline bold grey-text text-darken-3 margin-left"

这是在页面发送到浏览器之前在您的 Rails 服务器上评估的。

<script>
    var disqus_shortname = 'yourname';
    var disqus_identifier = '<%= url_for([product, {only_path: false}]) %>';
    var disqus_title = '<%= product.name %>';
    var disqus_url = '<%= url_for([product, {only_path: false}]) %>';
  (function() { // DON'T EDIT BELOW THIS LINE
     var d = document, s = d.createElement('script');
     s.src = 'https://url.disqus.com/embed.js';
     s.setAttribute('data-timestamp', +new Date());
     (d.head || d.body).appendChild(s);
  })();
</script>

此 javascript 稍后在客户端（用户浏览器）中运行 - 此时页面已由服务器发送。

如果您想知道在服务器端渲染时是否有任何评论，您需要从服务器调用 Disqus API。

Answer 2

我认为解决此问题的最佳方法是：

向您的数据库添加一个 comment_count 属性
添加一个 disqus onNewComment 回调来更新您记录中的评论数。

使用 Javascript 您可以添加回调：

var disqus_config = function () {
    this.callbacks.onNewComment = [
      function() {
        alert(comment.id);
        alert(comment.text);
        $.ajax({
          method: "PATCH",
          url: "<%= product_path(product) %>",
          data: {increment: "comment_count"}
        })
      }
    ];
};

然后你就会知道未来的评论数。

文档：https://help.disqus.com/customer/portal/articles/466258-capturing-disqus-commenting-activity-via-callbacks

将您的控制器更改为：

def update    
  product = Product.find(params[:id])
  if params[:comment_count]
    product.increment!(:comment_count)
  else
    product.update(update_product)
  end
end

如何仅在 returns > 0 时显示 link_to 助手

How to show a link_to helper only if it returns > 0

ruby

ruby-on-rails

view-helpers