香港邮政航空小包的计费方式是：挂号费+每公斤的费用。比如13+100/KG, 如果是100克，那么收费是13+0.1*100 = 23元。
Zen-cart中并没有符合这个计算逻辑的运费模块。参照现存的模块，自定义一个非常简单，需要先理解Zen-cart运费模块的工作模式，可参考：
// class methods function quote($method = ”) { global $order,$shipping_weight,$shipping_num_boxes,$db,$currencies; $total_weight = $shipping_weight * $shipping_num_boxes; if($total_weight > (int)MODULE_SHIPPING_HK_POST_MAX_WEIGHT){ return false; } //package weight $total_weight += (int)MODULE_SHIPPING_HK_POST_PACKAGE_WEIGHT; //////////////////// $cost = explode(‘,’,MODULE_SHIPPING_HK_POST_COST); $first = 13; $continue = 108; if(count($cost) >= 2){ $first = (int)$cost[0]; $continue = round($cost[1],2); }else{ $tmp = round($cost[0],2); if($tmp > 70){ $continue = $tmp; } } //////////////////// $rate = (float)$currencies->currencies[‘CNY’][‘value’]; if($rate <= 0){ $rate = 1; } $ttl = round(($first+$continue*ceil($total_weight/10)/100)/$rate,2); $this->quotes = array(‘id’ => $this->code, ‘module’ => MODULE_SHIPPING_HK_POST_TEXT_TITLE, ‘methods’ => array(array(‘id’ => $this->code, ‘title’ => MODULE_SHIPPING_HK_POST_TEXT_WAY, ‘cost’ => $ttl))); if ($this->tax_class > 0) { $this->quotes[‘tax’] = zen_get_tax_rate($this->tax_class, $order->delivery[‘country’][‘id’], $order->delivery[‘zone_id’]); } if (zen_not_null($this->icon)) $this->quotes[‘icon’] = zen_image($this->icon, $this->title); return $this->quotes; }
需要实现quote方法，这个方法按照如上返回对应内容。运费成本计算逻辑就一句代码：
| 1 | $ttl = round(($first+$continue*ceil($total_weight/10)/100)/$rate,2); |
注意，这里除以了人民币的汇率得到基准货币，那是因为插件后台设置的值为人民币为单位。插件其它代码参考Zen-cart默认的运费模块即可完成。
这里显示的运费就是根据上面的逻辑进行计算的。
