使用Javascript解析XML(在Google脚本中)

Question

我有温度传感器流式传输三个蜂箱的温度,并希望能够解析XML流以提供传感器的最后一个值.

我想:

• 传感器1:75度(更新时间:下午9:04)
• 传感器2:75度(更新时间:下午9:04)

等等

我在Google Scripts中运行以下脚本,但一直收到错误消息:

在对象<？xml version ="1.0"encoding ="UTF-8"中找不到函数getContentText？>

这是一个简单的脚本:

function XMLing() {

  var response = UrlFetchApp.fetch("https://api.cosm.com/v2/feeds/79697.xml?key=[private key here]");

  var doc = Xml.parse(response.getContentText(), true);
  var records = doc.getElements("current_value");
  var details = records[0].getText();

  return details;

}

这是XML:

<eeml xmlns="http://www.eeml.org/xsd/0.5.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="0.5.1" xsi:schemaLocation="http://www.eeml.org/xsd/0.5.1 http://www.eeml.org/xsd/0.5.1/0.5.1.xsd">
  <environment updated="2012-10-21T00:44:32.162393Z" created="2012-10-10T21:19:43.373591Z" id="79697" creator="https://cosm.com/users/greennomad">
    <private>false</private>
    <data id="sensor1tem">
      <current_value at="2012-10-21T00:44:32.019058Z">67.00</current_value>
      <max_value>618.0</max_value>
      <min_value>611.0</min_value>
    </data>
    <data id="sensor2tem">
      <current_value at="2012-10-21T00:44:32.019058Z">60.57</current_value>
      <max_value>61.5</max_value>
      <min_value>60.41</min_value>
    </data>
...

Answer 1

您可以检查哪些方法可用：

if (!response.getContentText) {
    var props = [];
    for (var p in response) {
        props.push(p);
    }

    var name = typeof response;
    if (response.contructor) name = response.contructor.name;

    return name + " { " + props.join(", ") + " }";
}

我的猜测是UrlFetchApp.fetch()要么返回一些错误代码，要么对 XML 文档有特殊响应。

从错误消息来看，似乎是UrlFetchApp.fetch()直接返回 XML 文档。您可能不需要致电Xml.parse()：

function XMLing() {

  var response = UrlFetchApp.fetch("https://api.cosm.com/v2/feeds/79697.xml?key=[private key here]");

  var doc = null;
  if (response.getContentText) {
    doc = Xml.parse(response.getContentText(), true);
  }
  else if (response.getElements) {
    doc = response;
  }
  else {
    var name = typeof response;
    if (response.constructor) name = response.constructor.name;
    throw new Exception("Incompatible type: " + name);
  }

  var records = doc.getElements("current_value");
  var details = records[0].getText();

  return details;

}