How to let golang distinguish XML elements with and without namespaces?

suppose I have the following XML data:

<image> 
  <url> http://sampleUrl.com
  </url>
</image>

<itunes:image url="http://sampleItunesUrl.com" />  //xmlData

I use this struct to decode it:

type Response struct {
   XMLName   xml.Name   `xml:"resp"`
   Image []struct {
        URL string   `xml:"url"`
  } `xml:"image"`
  ItunesImage  struct {
       URL string `xml:"url,attr"`
  }  `xml:"http://www.itunes.com/dtds/podcast-1.0.dtd image"`

}

and I have codes like:

var resp Response 
err := xml.Unmarshal([]byte(xmlData), &resp)
if err != nil {
	fmt.Printf("Error decoding XML: %s\n", err)
	return
}
for _, img := range resp.Image{
    if img.URL != "" {
        //<image>, not <itunes:image>
    }
}

to process decoding

The problem I am having is that looks like Image []struct considers both <image> and <itunes:image to be <image> element, since they both have "image". To filter out <itunes:image, the approach I am using is to let each one in Image []struct examine if their url are empty strings (because for <itunes:image its url is attribute).

Another approach is to write my own Unmarshal function to distinguish between XML elements with and without itunes namespace. Basically I want Image []struct to only hold elements <image>

I am wondering if go has some built-in functionalities to distinguish? Or I have to write my codes to filter out <itunes:image> ?

Please note that the field order matters. ItunesImage has a more specific tag, so it should go before Image.

package main

import (
	"encoding/xml"
	"fmt"
)

func main() {
	type Response struct {
		XMLName     xml.Name `xml:"resp"`
		ItunesImage struct {
			URL string `xml:"url,attr"`
		} `xml:"http://www.itunes.com/dtds/podcast-1.0.dtd image"`
		Image []struct {
			URL string `xml:"url"`
		} `xml:"image"`
	}

	xmlData := `
<resp xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd">
  <image>
    <url>http://sampleUrl.com</url>
  </image>
  <itunes:image url="http://sampleItunesUrl.com/" />
</resp>
`

	var resp Response
	err := xml.Unmarshal([]byte(xmlData), &resp)
	if err != nil {
		fmt.Printf("Error decoding XML: %s\n", err)
		return
	}
	fmt.Printf("ItunesImage: %v\n", resp.ItunesImage)
	fmt.Printf("Images: %v\n", resp.Image)
}

And if you only need image/url from the <image> tag, you could define the Response struct like this:

type Response struct {
	XMLName xml.Name `xml:"resp"`
	Image   []string `xml:"image>url"`
}

Regarding the general question in the title (How to let golang distinguish XML elements with and without namespaces?), you can capture the element name with a field named XMLName and examine the Space member of this field. See the demo below:

package main

import (
	"encoding/xml"
	"fmt"
)

func main() {
	type Response struct {
		XMLName xml.Name `xml:"resp"`
		Image   []struct {
			XMLName xml.Name
			URL     string `xml:"url"`
		} `xml:"image"`
	}

	xmlData := `
<resp xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd">
  <image>
    <url>http://sampleUrl.com</url>
  </image>
  <itunes:image>
    <url>http://sampleItunesUrl.com/</url>
  </itunes:image>
</resp>
`

	var resp Response
	err := xml.Unmarshal([]byte(xmlData), &resp)
	if err != nil {
		fmt.Printf("Error decoding XML: %s\n", err)
		return
	}
	for _, img := range resp.Image {
		fmt.Printf("namespace: %q, url: %s\n", img.XMLName.Space, img.URL)
	}
}

The output of the above demo is:

namespace: "", url: http://sampleUrl.com
namespace: "http://www.itunes.com/dtds/podcast-1.0.dtd", url: http://sampleItunesUrl.com/