make sitemap url limit adjustable

sitemap.go

@@ -4,6 +4,7 @@ import (
 	"encoding/xml"
 	"fmt"
 	"math"
+	"path"
 )
 
 type ChangeFrequency string
@@ -45,13 +46,14 @@ type sitemapXML struct {
 }
 
 type SiteMap struct {
-	urls    []*urlXML
-	BaseURL string
+	urls             []*urlXML
+	BaseURL          string
+	MaxURLPerSiteMap int
 }
 
 func (m *SiteMap) AddURL(url string, lastMod *string, freq *ChangeFrequency, prio *float64) {
 	m.urls = append(m.urls, &urlXML{
-		Loc:        fmt.Sprintf("https://%s/%s", m.BaseURL, url),
+		Loc:        fmt.Sprintf("https://%s", path.Join(m.BaseURL, url)),
 		LastMod:    lastMod,
 		ChangeFreq: freq,
 		Priority:   prio,
@@ -63,13 +65,12 @@ func prefixXML(content []byte) []byte {
 }
 
 func (m *SiteMap) SiteMapIndex() ([]byte, error) {
-	nSiteMaps := int(math.Floor(float64(len(m.urls))/50000 + 1))
-
+	nSiteMaps := int(math.Floor(float64(len(m.urls))/float64(m.MaxURLPerSiteMap) + 1))
 	index := &siteMapIndexXML{}
 
 	for i := 0; i < nSiteMaps; i++ {
 		index.SiteMaps = append(index.SiteMaps, &sitemapXML{
-			Loc: fmt.Sprintf("https://%s/sitemap%d.xml", m.BaseURL, i),
+			Loc: fmt.Sprintf("https://%s/sitemap/%d", m.BaseURL, i),
 		})
 	}
 
@@ -82,13 +83,17 @@ func (m *SiteMap) SiteMapIndex() ([]byte, error) {
 }
 
 func (m *SiteMap) SiteMap(id int) ([]byte, error) {
+	if m.MaxURLPerSiteMap*(id) >= len(m.urls) {
+		return nil, nil
+	}
+
 	siteMap := &urlSetXML{}
 
 	var urls []*urlXML
-	if 50000*(id+1) >= len(m.urls) {
-		urls = m.urls[50000*id:]
+	if m.MaxURLPerSiteMap*(id+1) >= len(m.urls) {
+		urls = m.urls[m.MaxURLPerSiteMap*id:]
 	} else {
-		urls = m.urls[50000*id : 50000*(id+1)]
+		urls = m.urls[m.MaxURLPerSiteMap*id : m.MaxURLPerSiteMap*(id+1)]
 	}
 
 	siteMap.URLs = append(siteMap.URLs, urls...)