使用属性作为值与动态节点映射XML

Question

I am attempting to convert data stored in xml documents into an alternative data store. I have tried a variety of techniques but none have proven effective. The problem is the xml does not have a fixed schema and has an unconventional structure. A sample of the xml is as follows

<?xml version="1.0"?>
<Data>
    <f.1 value="field value" />
    <f.2 value="other value" />
    <f.3 value="field value 2" />
    <withchildren>
        <f.3.1 value="testvalue" />
        <f.3.2 value="test value 3" />
    </withchildren>
</Data>

Ideally the end result should store the result in map[string]interface{} in order to convert the value into a standard multi-dimensional JSON format.

Answer 1

When you're unsure about the structure goquery is probably your best bet. Your tag names look a little odd I assume that's just for the sample. The code below uses the tag name for the key and uses the value attribute but you can modify it for any structure.

package main

import (
    "fmt"
    "github.com/PuerkitoBio/goquery"
    "strings"
)

func main() {
    xml := `
      <?xml version="1.0"?>
      <Data>
          <f1 value="field value"></f1>
          <f2 value="other value"></f2>
          <f3 value="field value 2"></f3>
          <withchildren>
              <f31 value="testvalue"></f31>
              <f32 value="test value 3"></f32>
          </withchildren>
      </Data>
      `
    data := make(map[string]interface{})
    reader := strings.NewReader(xml)

    doc, _ := goquery.NewDocumentFromReader(reader)
    children := doc.Find("Data").Children()

    children.Each(func(i int, s *goquery.Selection) {

        val, exists := s.Attr("value")
        if exists {
            data[goquery.NodeName(s)] = val
        }

        withchildren := s.Children()

        if withchildren.Length() > 0 {
            withchildren.Each(func(i int, s *goquery.Selection) {
                val, exists := s.Attr("value")
                if exists {
                    data[goquery.NodeName(s)] = val
                }

            })
        }
    })
    fmt.Println(data)
}

And if you really have no idea what the structure could be or how many nested elements there might be try this recursive version.

If you have multiple elements with the same name then you could modify the code to add a number with the key name. So "tag1", "tag2", etc.

package main

import (
    "github.com/PuerkitoBio/goquery"
    "strings"
)

func main() {
    xml := `
      <?xml version="1.0"?>
      <Data>
          <f1 value="field value"></f1>
          <f2 value="other value"></f2>
          <f3 value="field value 2"></f3>
          <withchildren>
              <f31 value="testvalue"></f31>
              <f32 value="test value 3"></f32>
          </withchildren>
      </Data>
      `
    data := make(map[string]interface{})
    reader := strings.NewReader(xml)

    doc, _ := goquery.NewDocumentFromReader(reader)
    children := doc.Find("Data").Children()
    data = getElements(children)
}

func getElements(children *goquery.Selection) map[string]interface{} {
    data := make(map[string]interface{})
    children.Each(func(i int, s *goquery.Selection) {
        val, exists := s.Attr("value")
        if exists {
            data[goquery.NodeName(s)] = val
        }

        if s.Children().Length() > 0 {
            data[goquery.NodeName(s)] = getElements(s.Children())
        }
    })
    return data
}

There are also some Go packages that I haven't used.

mxj converts xml to map[string]interface{}

goxml2json converts from xml to json.