基于购物车重量设置运费折扣的Shopify实现方案咨询

我刚接触Shopify，正在接手新店铺运营，需要实现基于购物车重量定义规则，自动生成折扣码或直接应用运费折扣的功能。之前做Web/移动应用时这类功能很容易实现，但不清楚在Shopify生态里该如何落地，想确认几个核心问题：

• 是否需要开发自定义应用？
• 如果需要开发自定义应用，如何改造结账页面来实现动态折扣逻辑？
• 目前正在学习开发自定义二维码应用，这是不是实现目标的正确方向？

已尝试的静态方案 #

之前使用过Script Editor应用配置静态折扣规则，代码如下：

{
    customer_tag_match_type: :include,
    customer_tags: ["SH123FREE"],
    rate_match_type: :exact,
    rate_names: ["EMS International Express",
    "By-Expressen - levering med bybud",
    "DHL Domestic Express (1 business day)",
    "DHL Economy EU (2-5 business days)",
    "DHL Economy (2-4 business days)",
    "DSV XPress Economy (6-10 business days)",
    "DSV XPress Economy (3-4 business days)",
    "DSV XPress USA (6-10 business days)"],
    discount_type: :percent,
    discount_amount: 100,
    discount_message: "Free shipping applied"
  },
  {
    customer_tag_match_type: :include,
    customer_tags: ["SH12350_OFF"],
    rate_match_type: :exact,
    rate_names: ["EMS International Express",
    "By-Expressen - levering med bybud",
    "DHL Domestic Express (1 business day)",
    "DHL Economy EU (2-5 business days)",
    "DHL Economy (2-4 business days)",
    "DSV XPress Economy (6-10 business days)",
    "DSV XPress Economy (3-4 business days)",
    "DSV XPress Economy USA (6-10 business days)"],
    discount_type: :percent,
    discount_amount: 50,
    discount_message: "50% off shipping applied"
  }

但该方案是静态配置，无法根据购物车重量动态调整折扣规则。

正在考虑的其他方案 #

我设想过部署AWS Lambda服务，在用户加载结账页面时传递购物车详情/重量，由Lambda返回预生成的静态折扣码并自动应用，但不确定Shopify是否支持这种对接方式。另外我们已经在创建静态折扣码供批发合作伙伴手动使用，现在希望明确自定义应用能否实现“按购物车重量动态触发运费折扣”的核心需求，恳请给出指导方向。

内容的提问来源于stack exchange，提问作者Manuel Maestrini