XML Namespaces Used by SunSitemap for Validation

SunSitemap declares the default Sitemaps namespace (http://www.sitemaps.org/schemas/sitemap/0.9) and the XML Schema Instance namespace (http://www.w3.org/2001/XMLSchema-instance) in every generated document to ensure strict validation against the official sitemap.xsd and siteindex.xsd schemas.

The msbatal/php-sitemap-generator library generates standards-compliant XML sitemaps used by search engines to crawl websites efficiently. Understanding the XML namespaces used by SunSitemap for validation ensures your sitemap files conform to the Sitemaps.org protocol and pass strict XML schema validation checks.

Default and XSI Namespace Declarations

SunSitemap generates two distinct XML document types depending on the number of URLs added. Both document types declare identical namespace prefixes but reference different schema definition files via the xsi:schemaLocation attribute.

The urlset Root Element (Lines 94-99)

For standard sitemap files containing URL entries, SunSitemap constructs a <urlset> root element in SunSitemap.php (lines 94-99) with the following namespace declarations:

<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">

The default namespace (xmlns) defines core Sitemap elements including <url>, <loc>, <lastmod>, <changefreq>, and <priority>. The xsi namespace enables schema validation by referencing the official sitemap.xsd file.

The sitemapindex Root Element (Lines 220-225)

When the URL count exceeds the configured limit and multiple sitemap files are generated, SunSitemap creates a sitemap index document using a <sitemapindex> root element (lines 220-225 of SunSitemap.php):

<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/siteindex.xsd"
    xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">

Notice that while the namespace URIs remain identical, the xsi:schemaLocation attribute points to siteindex.xsd instead of sitemap.xsd to validate the index structure rather than individual URL entries.

How createSitemap() Injects Namespaces

The createSitemap() method automatically constructs the appropriate XML header based on whether the script generates a single sitemap file or requires a sitemap index. You do not manually specify these namespaces; SunSitemap inserts them during the XML generation process to guarantee validation compliance.

When createSitemap() executes, it:

1. Determines whether to build a <urlset> or <sitemapindex> document
2. Injects the default namespace URI http://www.sitemaps.org/schemas/sitemap/0.9
3. Adds the xmlns:xsi declaration for schema instance validation
4. Sets the correct xsi:schemaLocation attribute pointing to either sitemap.xsd or siteindex.xsd

Practical Usage Example

The following PHP implementation demonstrates how SunSitemap automatically handles XML namespaces during sitemap generation:

<?php
require_once 'SunSitemap.php';

// Initialize the generator
$sitemap = new SunSitemap('https://example.com', 'sitemap/');

// Add URLs to the sitemap
$sitemap->addUrl('page1.html', '2024-01-01', 'monthly', '0.8')
        ->addUrl('page2.html', '2024-01-02', 'weekly', '0.5');

// Generate files with automatic namespace injection
$sitemap->createSitemap()
        ->updateRobots();
?>

Running this code produces XML files containing the validation namespaces at the root element, ensuring immediate compatibility with Google Search Console and other search engine validators without manual XML manipulation.

Summary

• SunSitemap.php declares two XML namespaces in lines 94-99 and 220-225 to support schema validation.
• The default namespace (http://www.sitemaps.org/schemas/sitemap/0.9) defines all core Sitemap protocol elements.
• The xsi namespace (http://www.w3.org/2001/XMLSchema-instance) enables xsi:schemaLocation attributes that reference official XSD files.
• Standard sitemaps validate against sitemap.xsd, while sitemap indexes validate against siteindex.xsd.
• The createSitemap() method automatically injects these declarations; no manual namespace configuration is required.

Frequently Asked Questions

Can I customize the XML namespaces in SunSitemap?

No, the namespace URIs are hardcoded in SunSitemap.php to ensure compliance with the official Sitemaps.org protocol. Modifying these would break validation against the standard schemas used by Google, Bing, and other search engines.

Why does SunSitemap use two different schemaLocation values?

The xsi:schemaLocation attribute points to sitemap.xsd for <urlset> documents (individual URL listings) and siteindex.xsd for <sitemapindex> documents (lists of sitemap files). This distinction ensures the XML structure matches the appropriate schema definition for each document type.

Are these namespaces required for search engine submission?

While search engines may parse sitemaps without strict schema validation, declaring these namespaces ensures the XML passes formal validation tests and prevents parsing errors. The msbatal/php-sitemap-generator repository includes these namespaces by default to guarantee maximum compatibility.

Where are the namespace declarations located in the source code?

In SunSitemap.php, the <urlset> namespace declarations appear at lines 94-99, while the <sitemapindex> declarations are found at lines 220-225. Both sections construct the root element string that includes the xmlns, xmlns:xsi, and xsi:schemaLocation attributes.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}