Go: promoted fields in nested struct for XML decoding

I have a XML transfered struct as below :

type urlset struct {
	XMLName xml.Name `xml:"urlset"`
	URL     []struct {
		Loc  string `xml:"loc"`
		News struct {
			Publishdate string `xml:"publication_date"`
			Title       string `xml:"title"`
			Summary     string `xml:"keywords"`
		} `xml:"news"`
	} `xml:"url"`
}

What I should do if I want to promote fields in the nested structure News ?

I hope I can directly access News' fields and print the value as below

var URLset urlset
if xmlBytes, err := getXML(url); err != nil {
	fmt.Printf("Failed to get XML: %v", err)
} else {
	xml.Unmarshal(xmlBytes, &URLset)
}
/************************** XML parser *************************/
for _, URLElement := range URLset.URL {
fmt.Println(
	"[Element]:",
	"\nTitle #", URLElement.title,
	"\nPublicationDate #", URLElement.Publishdate,
	"\nSummary#", URLElement.Summary,
    	"\nLoc #", URLElement.Loc, "\n")
}

Here is the complete code of mine Go Playground

Omit name will embed to self.

example

package main
import "fmt"
type Animal struct {
Name string
}
type Cat struct {
Animal // 👈 Omit name
}
type Dog struct {
A Animal // 👈 have name "A"
}
func main() {
cat := Cat{Animal{"Kitty"}}
fmt.Println(cat.Name)        // OK
fmt.Println(cat.Animal.Name) // OK too
dog := Dog{Animal{"Snoopy"}}
// fmt.Println(dog.Name)   // Error: type Dog has no field or method Name
fmt.Println(dog.A.Name) // OK too
}

<kbd>go playground</kbd>

your case

see 👈 are enough (others same as yours.)

package main

import (
	"encoding/xml"
	"fmt"
	"io/ioutil"
	"net/http"
)

type News struct { // 👈 move to here
	Publishdate string `xml:"news>publication_date"` // 👈 Use ">" to tell its parent. https://github.com/golang/go/blob/0a1a092c4b56a1d4033372fbd07924dad8cbb50b/src/encoding/xml/typeinfo.go#L198-L199
	Title       string `xml:"news>title"`
	Summary     string `xml:"news>keywords"`
}

type urlset struct {
	XMLName xml.Name `xml:"urlset"`
	URL     []struct {
		Loc  string `xml:"loc"`
		News `xml:"news"` // 👈 do not give the name
	} `xml:"url"`
}

func getXML(url string) ([]byte, error) {
	resp, err := http.Get(url)
	if err != nil {
		return []byte{}, fmt.Errorf("GET error: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return []byte{}, fmt.Errorf("Status error: %v", resp.StatusCode)
	}

	data, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return []byte{}, fmt.Errorf("Read body: %v", err)
	}
	return data, nil
}

func main() {

	var URLset urlset
	/* To avoid the link not working in the future, I write the value directly.
	url := "https://www.dw.com/de/news-sitemap.xml"
	if xmlBytes, err := getXML(url); err != nil {
		fmt.Printf("Failed to get XML: %v", err)
	} else {
		xml.Unmarshal(xmlBytes, &URLset)
	}
	*/

	xmlBytes := []byte(`
<urlset>
	<url>
		<loc>https://www.dw.com/de/kopf-an-kopf-rennen-bei-parlamentswahl-in-australien/a-61887162</loc>
		<news:news>
			<news:publication>
				<news:name>Deutsche Welle</news:name>
				<news:language>de</news:language>
			</news:publication>
			<news:publication_date>2022-05-21T11:28:55.875Z</news:publication_date>
			<news:title>Kopf-an-Kopf-Rennen bei Parlamentswahl in Australien</news:title>
			<news:keywords>Australien,Parlamentswahl,Scott Morrison,Anthony Albanese,Labor-Partei,Liberale</news:keywords>
		</news:news>
		<image:image>
			<image:loc>https://static.dw.com/image/61872101_403.jpg</image:loc>
			<image:caption>Der australische Premierminister Scott Morrison (r.) und sein Herausforderer, Oppositionsführer Anthony Albanese</image:caption>
		</image:image>
	</url>
	<url>
		<loc>https://www.dw.com/de/ukraine-aktuell-selenskyj-verlangt-entsch%C3%A4digungsfonds/a-61885143</loc>
		<news:news>
			<news:publication>
				<news:name>Deutsche Welle</news:name>
				<news:language>de</news:language>
			</news:publication>
			<news:publication_date>2022-05-21T11:10:21.813Z</news:publication_date>
			<news:title>Ukraine aktuell: Selenskyj verlangt Entschädigungsfonds</news:title>
			<news:keywords>Ukraine,Krieg,Russland,Wolodymyr Selenskyj,Wladimir Putin,Mariupol</news:keywords>
		</news:news>
		<image:image>
			<image:loc>https://static.dw.com/image/61885205_403.jpg</image:loc>
			<image:caption>75. Filmfestival Cannes | Rede von Wolodymyr Selenskyj</image:caption>
		</image:image>
	</url>
<urlset>
`)

	xml.Unmarshal(xmlBytes, &URLset)
	/************************** XML parser *************************/
	for _, URLElement := range URLset.URL {
		/*
		   fmt.Println(
		       "[Element]:",
		       "\nTitle #", URLElement.News.Title,
		       "\nPublicationDate #", URLElement.News.Publishdate,
		       "\nSummary#", URLElement.News.Summary,
		       "\nLoc #", URLElement.Loc, "\n")
		*/

		fmt.Println( // 👈 Now, this work!
			"[Element]:",
			"\nTitle #", URLElement.Title,
			"\nPublicationDate #", URLElement.Publishdate,
			"\nSummary#", URLElement.Summary,
			"\nLoc #", URLElement.Loc, "\n")
	}
}

About the XML Namespaces

• XML Namespaces provide a method to avoid element name conflicts.
• marshal.go
• read.go
• typeinfo.go: Prepare field name and parents. Now you know why it is ">"

More Examples

• ExampleUnmarshal This link is from go/src/encoding/xml/example_test.go In fact, all the examples are easy to understand. So it's good for learning.