在Go中解析XML时处理名称空间

Question

I am trying to parse a piece if XML in Go:

package main

import (
    "encoding/xml"
    "fmt"
)

type XML struct {
    Foo string `xml:"foo"`
}

func main() {
    rawXML := []byte(`
<xml>
  <foo>A</foo>
  <ns:foo>B</ns:foo>
</xml>`)

    x := new(XML)
    xml.Unmarshal(rawXML, x)
    fmt.Printf("foo: %s
", x.Foo)
}

This outputs:

foo: B

While I expected it to produce:

foo: A

How do I get content of the first foo tag (i.e. one without namespace)?

Answer 1

I don't think the xml decoder can specify an element should have no namespace with struct tags. But I do know that it can retrieve the information about the namespaces for you and you could then post process the data after to get the same result:

package main

import (
    "encoding/xml"
    "fmt"
)

type Foo struct {
    XMLName xml.Name
    Data string `xml:",chardata"`
}

type XML struct {
    Foo []Foo `xml:"foo"`
}

func main() {
    rawXML := []byte(`
<xml>
  <foo>A</foo>
  <ns:foo>B</ns:foo>
</xml>`)

    x := new(XML)
    xml.Unmarshal(rawXML, x)
    //fmt.Printf("foo: %#v
", x)
    for _, el := range x.Foo {
       if el.XMLName.Space == "" {
          fmt.Printf("non namespaced foo %q", el.Data)
      }
    }
}

http://play.golang.org/p/aDEFPmHPc0