GoLang-具有HTML的XmlPath选择器

Question

I am looking at the documented example here , but it is iterating purely over an XML tree, and not HTML. Therefore, I am still partly confused.

For example, if I wanted to find a specific meta tag within the head tag by name, it seems I cannot? Instead, I need to find it by the order it is in the head tag. In this case, I want the 8th meta tag, which I assume is:

headTag, err := getByID(xmlroot, "/head/meta[8]/")

But of course, this is using a getByID function for a tag name - which I don't believe will work. What is the full list of "getBy..." commands?

Then, the problem is, how do I access the meta tag's contents? The documentation only provides examples for the inner tag node content. However, will this example work?:

resp.Query = extractValue(headTag, @content )

The @ selector confuses me, is this appropriate for this case?

In other words:

1. Is there a proper HTML example available?
2. Is there a list of correct selectors for IDs, Tags, etc?
3. Can Tags be found by name, and content extracted from its inner content tag?

Thank you very much!

Answer 1

XPath does not seem suitable here; you should be using goquery , which is designed for HTML.

Here is an example:

package main

import (
    "fmt"

    "github.com/PuerkitoBio/goquery"
)

func main() {
    doc, err := goquery.NewDocument("https://example.com")
    if err != nil {
        panic(err)
    }
    s := doc.Find(`html > head > meta[name="viewport"]`)
    if s.Length() == 0 {
        fmt.Println("could not find viewpoint")
        return
    }
    fmt.Println(s.Eq(0).AttrOr("content", ""))
}

Answer 2

I know this answer is late, but I still want to recommend an htmlquery package that is simple and powerful, based on XPath expressions*.

The below code based on @Time-Cooper example.

package main

import (
    "fmt"

    "github.com/antchfx/htmlquery"
)

func main() {
    doc, err := htmlquery.LoadURL("https://example.com")
    if err != nil {
        panic(err)
    }
    s := htmlquery.Find(doc, "//meta[@name='viewport']")
    if len(s) == 0 {
        fmt.Println("could not find viewpoint")
        return
    }
    fmt.Println(htmlquery.SelectAttr(s[0], "content"))

    // alternative method,but simple more.
    s2 := htmlquery.FindOne(doc, "//meta[@name='viewport']/@content")
    fmt.Println(htmlquery.InnerText(s2))
}