Golang：使用xml.decode从xml获取内部xml

Question

I have simple XML like this:

<?xml version="1.0" encoding="ISO-8859-1"?>
  <nexgen_audio_export>
    <audio ID="id_1667331726_30393658">
      <type>Song</type>
      <status>Playing</status>
      <played_time>09:41:18</played_time>
      <composer>Frederic Delius</composer>
      <title>Violin Sonata No.1</title>
      <artist>Tasmin Little, violin; Piers Lane, piano</artist>
      <comments>
         <p>Comment line1</p>
         <p>Comment <b>line2</b></p>
         <p>Comment line3</p>
      </comments>
    </audio>
  </nexgen_audio_export>

How can I get inner XML from xml:"nexgen_audio_export>audio>comments" with all tags (<p>, <b>, etc) using xml.decode?

Thank you, AP

Answer 1

From https://golang.org/pkg/encoding/xml/#Unmarshal:

If the struct has a field of type []byte or string with tag ",innerxml", Unmarshal accumulates the raw XML nested inside the element in that field.

You can just use the struct tag ",innerxml" to a field of type string or []byte that's inside the element you're trying to extract XML from. You'll need to use a sub-struct. Also note that the selection query of the XML library starts at the first element (It's quite strange). So you can't start the tag with nexgen_audio_export>, but rather go straight to audio>.

Here's working example code:

package main

import (
    "encoding/xml"
    "fmt"
)

// Encoding had to be changed to UTF-8
var input = []byte(`<?xml version="1.0" encoding="UTF-8"?>
  <nexgen_audio_export>
    <audio ID="id_1667331726_30393658">
      <type>Song</type>
      <status>Playing</status>
      <played_time>09:41:18</played_time>
      <composer>Frederic Delius</composer>
      <title>Violin Sonata No.1</title>
      <artist>Tasmin Little, violin; Piers Lane, piano</artist>
      <comments>
         <p>Comment line1</p>
         <p>Comment <b>line2</b></p>
         <p>Comment line3</p>
      </comments>
    </audio>
  </nexgen_audio_export>`)

type audio struct {
    Comments struct {
        InnerXML string `xml:",innerxml"`
    } `xml:"audio>comments"`
}

func main() {
    var a audio
    err := xml.Unmarshal(input, &a)
    if err != nil {
        panic(err)
    }

    fmt.Println(a.Comments.InnerXML)
}

Playground link: https://play.golang.org/p/LAL2V0zExc