Generating xml sitemap with Golang

sitemaps are xml based files shared for search engines. Main purpose of sitemap is making websites easy indexable

golang library encoding/xml contains functions for marshalling & unmarshalling xml data format

Sitemap xml structure

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
   <url>
      <loc>http://33m.org/</loc>
      <lastmod>2024-12-01</lastmod>
      <changefreq>monthly</changefreq>
      <priority>0.9</priority>
   </url>
</urlset> 

Url tag contains :

loc tag indicates page url (required)

lastmod tag indicates last modification date

changefreq indicates page update frequency

priority tag indicates page priority

Sitemap Index file

if we have multiple sitemap, we can add all sitemaps to the one sitemap index file

sitemap index file structure

<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
   <sitemap>
      <loc>http://33m.org/sitemap.xml</loc>
      <lastmod>2024-12-12T18:23:17+00:00</lastmod>
   </sitemap>
   <sitemap>
      <loc>http://33m.org/sitemap2.xml</loc>
      <lastmod>2024-12-22</lastmod>
   </sitemap>
</sitemapindex>

tags under the sitemap tag have same function with url tag.

only we need to add sitemap url

Golang encoding/xml library

encoding/xml library supports Marshalling & Unmarshalling xml

lets create a example sitemap with Golang

Declaration of object structures for sitemap

type UrlSet struct {
	XMLName           xml.Name `xml:"urlset"`
	Url               []Url    `xml:"url"`
	Xsi               string   `xml:"xmlns:xsi,attr"`
	XsiSchemaLocation string   `xml:"xsi:schemaLocation,attr"`
	Xmlns             string   `xml:"xmlns,attr"`
}

type Url struct {
	Loc     string  `xml:"loc"`
	Lastmod *string `xml:"lastmod"`
}

Creating Instance of Urlset Object

locs := []Url{}
locs = append(locs, Url{Loc: "http://33m.org/golang", Lastmod: "2024-12-12"})
locs = append(locs, Url{Loc: "http://33m.org/java", Lastmod: "2024-11-12"})
locs = append(locs, Url{Loc: "http://33m.org/linux", Lastmod: "2024-11-12"})

urlSet := UrlSet{
		Url:               locs,
		Xmlns:             "http://www.sitemaps.org/schemas/sitemap/0.9",
		XsiSchemaLocation: "http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd",
		Xsi:               "http://www.w3.org/2001/XMLSchema-instance",
	}

Using different namespaces are possible, we use default sitemap schema (http://www.sitemaps.org/schemas/sitemap/0.9)

Marshalling

xmlBytes, err := xml.Marshal(urlSet)
if err != nil {
	panic(err)
}

fmt.Println(string(xmlBytes))

Result :

<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"
    xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <url>
        <loc>http://33m.org/golang</loc>
        <lastmod>2024-12-12</lastmod>
    </url>
    <url>
        <loc>http://33m.org/java</loc>
        <lastmod>2024-12-12</lastmod>
    </url>
    <url>
        <loc>http://33m.org/linux</loc>
        <lastmod>2024-12-12</lastmod>
    </url>
</urlset>

Declaration of object structures for sitemap index

type SitemapIndex struct {
	XMLName           xml.Name  `xml:"sitemapindex"`
	Sitemap           []Sitemap `xml:"sitemap"`
	Xsi               string    `xml:"xmlns:xsi,attr"`
	XsiSchemaLocation string    `xml:"xsi:schemaLocation,attr"`
	Xmlns             string    `xml:"xmlns,attr"`
}

type Sitemap struct {
	Loc     string  `xml:"loc"`
	Lastmod *string `xml:"lastmod"`
}

Creating instance of SitemapIndex Object

sitemaps := []Sitemap{}
sitemaps = append(sitemaps, Sitemap{Loc: "http://33m.org/sitemap1.xml"})
sitemaps = append(sitemaps, Sitemap{Loc: "http://33m.org/sitemap2.xml"})


sitemapIndex := SitemapIndex{
		Sitemap:           sitemaps,
		Xmlns:             "http://www.sitemaps.org/schemas/sitemap/0.9",
		XsiSchemaLocation: "http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd",
		Xsi:               "http://www.w3.org/2001/XMLSchema-instance",
	}

Marshalling

xmlBytes, err := xml.Marshal(sitemapIndex)
if err != nil {
	panic(err)
}

fmt.Println(string(xmlBytes))

Result :

<sitemapindex xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"
    xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <sitemap>
        <loc>http://33m.org/sitemap1.xml</loc>
    </sitemap>
    <sitemap>
        <loc>http://33m.org/sitemap2.xml</loc>
    </sitemap>
</sitemapindex>