[xpath] XPATH
xpath 是补全 yak 对 html 处理能力的一个环节，这个内置模块本质上是对 htmlquery 的精简与再封装。
API#
fn xpath.CreateXPathNavigator(var_1: *html.Node): *htmlquery.NodeNavigatorfn xpath.ExistedAttr(var_1: *html.Node, var_2: string): boolfn xpath.Find(var_1: *html.Node, var_2: string): []*html.Nodefn xpath.FindOne(var_1: *html.Node, var_2: string): *html.Nodefn xpath.InnerText(var_1: *html.Node): stringfn xpath.LoadHTMLDocument(var_1: interface {}): (*html.Node, error)fn xpath.OutputHTML(var_1: *html.Node): stringfn xpath.OutputHTMLSelf(var_1: *html.Node): stringfn xpath.Query(var_1: *html.Node, var_2: string): (*html.Node, error)fn xpath.QueryAll(var_1: *html.Node, var_2: string): ([]*html.Node, error)fn xpath.SelectAttr(var_1: *html.Node, var_2: string): string案例: 使用 xpath.Find 来查询 HTML 节点#
在使用查询 API 之前，我们需要通过 xpath.LoadHTMLDocument 来生成一个 HTML 可操作文档，然后把文档的实例传递给其他的查询参数获取内容。
doc, err := xpath.LoadHTMLDocument(`<!DOCTYPE html><html lang="en-US"><head><title>Hello,World!</title></head><body><div class="container"><header> <!-- Logo --> <h1>City Gallery</h1></header> <nav> <ul> <li><a href="/London">London</a></li> <li><a href="/Paris">Paris</a></li> <li><a href="/Tokyo">Tokyo</a></li> </ul></nav><article> <h1>London</h1> <img src="pic_mountain.jpg" alt="Mountain View" style="width:304px;height:228px;"> <p>London is the capital city of England. It is the most populous city in the United Kingdom, with a metropolitan area of over 13 million inhabitants.</p> <p>Standing on the River Thames, London has been a major settlement for two millennia, its history going back to its founding by the Romans, who named it Londinium.</p></article><footer>Copyright © W3Schools.com</footer></div></body></html>`)die(err)
nodes := xpath.Find(doc, "//p")for _, node := range nodes { println(xpath.InnerText(node))}