简单GET请求
问题
您想对一个网站发起一个简单的GET请求并提取有用的信息。
解决方案
使用HTTP请求节点发起HTTP请求，并使用HTML节点从检索到的HTML文档中提取元素。
示例
[{"id":"d88dd470.0ac7b8","type":"inject","z":"18c99b30.cf9d35","name":"make request","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"x":130,"y":180,"wires":[["874a3d4e.9b666"]]},{"id":"874a3d4e.9b666","type":"http request","z":"18c99b30.cf9d35","name":"","method":"GET","ret":"txt","url":"https://nodered.com.cn","tls":"","x":294.5,"y":180,"wires":[["90243cc1.87edc"]]},{"id":"7403c68f.21d7c8","type":"debug","z":"18c99b30.cf9d35","name":"","active":true,"console":"false","complete":"false","x":650,"y":180,"wires":[]},{"id":"90243cc1.87edc","type":"html","z":"18c99b30.cf9d35","name":"","property":"","tag":".node-red-latest-version","ret":"text","as":"single","x":471.5,"y":180,"wires":[["7403c68f.21d7c8"]]}]
讨论
要查找网页中的内容，Chrome浏览器的“检查元素”是一个很有用的工具。使用浏览器，右键点击页面元素，可以查看应用于该元素的标签、ID和类，如图所示。
在此示例中，我们从https://nodered.com.cn检索Node-RED的最新版本。使用检查器，我们可以看到版本位于一个带有类node-red-latest-version的<span>标签中。
HTML节点可以配置CSS选择器.node-red-latest-version，为每个匹配的元素返回一条消息。
