feat: Google News sitemap

- sitemap-news.xml lists the articles (content kind article) first
  published in the last two days, newest first, at most 1000, with the
  publication name (news_publication, else app.name), the language of the
  locale, the publication date and the title
- news_sources narrows it to type:<key> and category:<key>:<id> values;
  the Images and News tab lists the values to use in a partial
- the index lists the file while news_enabled is on; otherwise it is 404

classes/news.go

@@ -0,0 +1,239 @@
+package classes
+
+import (
+	"bufio"
+	"encoding/xml"
+	"io"
+	"strings"
+	"time"
+
+	"git.golem15.com/golem15/sm-sitemap-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"git.golem15.com/golem15/summercms/modules/signpost"
+	"gorm.io/gorm"
+)
+
+// NSNews is the namespace of the Google News sitemap.
+const NSNews = "http://www.google.com/schemas/sitemap-news/0.9"
+
+// NewsFile is the name of the News sitemap file.
+const NewsFile = "sitemap-news.xml"
+
+// The News sitemap's limits (RESEARCH Pitfall 9): articles first published
+// in the last NewsWindow, at most MaxNewsEntries.
+const (
+	NewsWindow     = 48 * time.Hour
+	MaxNewsEntries = 1000
+)
+
+// NewsEntry is one <url> of the News sitemap: the article's absolute
+// address, the publication name and language, its first publication and
+// its title.
+type NewsEntry struct {
+	Loc         string
+	Publication string
+	Language    string
+	Published   time.Time
+	Title       string
+}
+
+// The prefixes of the news_sources values (P33-15).
+const (
+	NewsSourceType     = models.NewsSourceType
+	NewsSourceCategory = models.NewsSourceCategory
+)
+
+// newsSources are the parsed news_sources values: the article types and
+// the parents listed.
+type newsSources struct {
+	types   map[string]bool
+	parents map[models.Ref]bool
+}
+
+// parseNewsSources reads the news_sources values; a value of another form
+// is ignored (the settings refuse it on save).
+func parseNewsSources(values []string) newsSources {
+	out := newsSources{types: map[string]bool{}, parents: map[models.Ref]bool{}}
+	for _, v := range values {
+		switch {
+		case strings.HasPrefix(v, NewsSourceType):
+			if key := strings.TrimPrefix(v, NewsSourceType); key != "" {
+				out.types[key] = true
+			}
+		case strings.HasPrefix(v, NewsSourceCategory):
+			rest := strings.TrimPrefix(v, NewsSourceCategory)
+			if i := strings.LastIndex(rest, ":"); i > 0 && i < len(rest)-1 {
+				out.parents[models.Ref{Type: rest[:i], ID: rest[i+1:]}] = true
+			}
+		}
+	}
+	return out
+}
+
+// empty reports whether no source is listed: every article type is.
+func (s newsSources) empty() bool { return len(s.types) == 0 && len(s.parents) == 0 }
+
+// matches reports whether an article of typeKey with parents is listed:
+// its type or one of its parents is (P33-15).
+func (s newsSources) matches(typeKey string, parents []models.Ref) bool {
+	if s.empty() || s.types[typeKey] {
+		return true
+	}
+	for _, p := range parents {
+		if s.parents[p] {
+			return true
+		}
+	}
+	return false
+}
+
+// NewsLanguage is the News language code of a locale: the lowercase
+// primary subtag (pl-PL: pl), except Chinese, which Google names zh-cn or
+// zh-tw.
+func NewsLanguage(locale string) string {
+	l := strings.ToLower(strings.ReplaceAll(strings.TrimSpace(locale), "_", "-"))
+	if l == "zh-tw" || l == "zh-hant" || strings.HasPrefix(l, "zh-hant-") {
+		return "zh-tw"
+	}
+	if l == "zh" || strings.HasPrefix(l, "zh-") {
+		return "zh-cn"
+	}
+	if i := strings.IndexByte(l, '-'); i > 0 {
+		return l[:i]
+	}
+	return l
+}
+
+// NewsPublication is the publication name of the News sitemap: the
+// news_publication setting, else the config key app.name.
+func NewsPublication(app *backpack.App, s models.Settings) string {
+	if name := strings.TrimSpace(models.Text(s.NewsPublication)); name != "" {
+		return name
+	}
+	if app != nil && app.Config != nil {
+		return strings.TrimSpace(app.Config.String("app.name"))
+	}
+	return ""
+}
+
+// NewsEntries lists the News sitemap's articles (D-31, RESEARCH Pitfall 9):
+// listed addresses of content types of kind article first published within
+// NewsWindow before now, of the news_sources (every article type when none
+// is listed), newest first, at most MaxNewsEntries. An address without a
+// locale takes the default_locale setting, else app.locale.
+func NewsEntries(db *gorm.DB, app *backpack.App, s models.Settings, now time.Time) ([]NewsEntry, error) {
+	sources := parseNewsSources(s.Sources())
+	q := db.Model(&models.URL{}).
+		Where("kind = ? AND excluded_reason = '' AND published_at IS NOT NULL AND published_at >= ? AND published_at <= ?", pact.ContentKindArticle, now.Add(-NewsWindow), now).
+		Order("published_at DESC, id DESC")
+	if sources.empty() {
+		q = q.Limit(MaxNewsEntries)
+	}
+	var rows []models.URL
+	if err := q.Find(&rows).Error; err != nil {
+		return nil, err
+	}
+	site := SiteURL(app, s)
+	publication := NewsPublication(app, s)
+	fallback := models.Text(s.DefaultLocale)
+	if fallback == "" && app != nil && app.Config != nil {
+		fallback = app.Config.String("app.locale")
+	}
+	out := make([]NewsEntry, 0, min(len(rows), MaxNewsEntries))
+	for _, r := range rows {
+		if len(out) == MaxNewsEntries {
+			break
+		}
+		if !sources.matches(r.TypeKey, r.ParentRefs.Get()) {
+			continue
+		}
+		loc := Absolute(site, r.URL)
+		if loc == "" || r.PublishedAt == nil {
+			continue
+		}
+		locale := r.Locale
+		if locale == "" {
+			locale = fallback
+		}
+		title := strings.TrimSpace(r.Title)
+		if title == "" {
+			title = loc
+		}
+		out = append(out, NewsEntry{Loc: loc, Publication: publication, Language: NewsLanguage(locale), Published: r.PublishedAt.UTC(), Title: title})
+	}
+	return out, nil
+}
+
+// WriteNewsURLSet writes the News sitemap: a <url> per article with its
+// <loc> and news:news (news:publication with news:name and news:language,
+// news:publication_date and news:title).
+func WriteNewsURLSet(w io.Writer, entries []NewsEntry) error {
+	bw := bufio.NewWriter(w)
+	bw.WriteString(xml.Header)
+	bw.WriteString(`<urlset xmlns="` + NSSitemap + `" xmlns:news="` + NSNews + `">`)
+	for _, e := range entries {
+		bw.WriteString("\n<url><loc>")
+		escape(bw, e.Loc)
+		bw.WriteString("</loc><news:news><news:publication><news:name>")
+		escape(bw, e.Publication)
+		bw.WriteString("</news:name><news:language>")
+		escape(bw, e.Language)
+		bw.WriteString("</news:language></news:publication><news:publication_date>")
+		bw.WriteString(lastmod(e.Published))
+		bw.WriteString("</news:publication_date><news:title>")
+		escape(bw, e.Title)
+		bw.WriteString("</news:title></news:news></url>")
+	}
+	bw.WriteString("\n</urlset>\n")
+	return bw.Flush()
+}
+
+// NewsSource is one value the news_sources setting may take, with what it
+// lists: Type is the content type key, ID the category's record ID ("" for
+// a whole type) and Title the category's title.
+type NewsSource struct {
+	Value string `json:"value"`
+	Type  string `json:"type"`
+	ID    string `json:"id,omitempty"`
+	Title string `json:"title,omitempty"`
+}
+
+// maxNewsSourceCategories caps the categories NewsSources lists.
+const maxNewsSourceCategories = 500
+
+// NewsSources lists the values news_sources may take (P33-15): type:<key>
+// for every content type of kind article, then category:<key>:<id> for
+// every parent the listed articles name (their categories), with its title
+// from the slot table (the default locale's first), at most 500.
+func NewsSources(db *gorm.DB, reg *signpost.Registry, defaultLocale string) ([]NewsSource, error) {
+	out := []NewsSource{}
+	if reg != nil {
+		for _, typ := range reg.ContentTypes() {
+			if typ.Content != nil && typ.Content.Kind == pact.ContentKindArticle {
+				out = append(out, NewsSource{Value: NewsSourceType + typ.Key, Type: typ.Key})
+			}
+		}
+	}
+	var rows []struct {
+		Type  string `gorm:"column:type"`
+		ID    string `gorm:"column:id"`
+		Title string `gorm:"column:title"`
+	}
+	if err := db.Raw(`SELECT DISTINCT ON (p.type, p.id) p.type, p.id, COALESCE(c.title, '') AS title
+FROM (SELECT DISTINCT r->>'type' AS type, r->>'id' AS id
+      FROM golem15_sitemap_urls u, jsonb_array_elements(u.parent_refs) r
+      WHERE u.kind = ? AND u.excluded_reason = '') p
+LEFT JOIN golem15_sitemap_urls c ON c.type_key = p.type AND c.record_id = p.id
+ORDER BY p.type, p.id, (c.locale = ?) DESC, c.id
+LIMIT ?`, pact.ContentKindArticle, defaultLocale, maxNewsSourceCategories).Scan(&rows).Error; err != nil {
+		return nil, err
+	}
+	for _, r := range rows {
+		v := NewsSourceCategory + r.Type + ":" + r.ID
+		if models.ValidNewsSource(v) {
+			out = append(out, NewsSource{Value: v, Type: r.Type, ID: r.ID, Title: r.Title})
+		}
+	}
+	return out, nil
+}

controllers/settings.go

@@ -12,6 +12,7 @@ import (
 	"git.golem15.com/golem15/summercms/modules/cabana"
 	"git.golem15.com/golem15/summercms/modules/pact"
 	"git.golem15.com/golem15/summercms/modules/phrasebook"
+	"git.golem15.com/golem15/summercms/modules/signpost"
 	"gorm.io/gorm"
 )
 
@@ -129,9 +130,76 @@ type reasonRow struct {
 // and the index note; files.empty before the first build and
 // files.building while a rebuild asked for from the admin runs.
 func (c settingsAdminController) PartialData(ctx context.Context, name string, _ any) (any, error) {
-	if name != "sitemap_files" {
-		return nil, nil
+	switch name {
+	case "sitemap_files":
+		return c.filesData(ctx)
+	case "news_sources":
+		return c.newsSourcesData(ctx)
 	}
+	return nil, nil
+}
+
+// sourceRow is one row of the news_sources partial: the value to enter and
+// what it lists.
+type sourceRow struct {
+	Value string
+	Label string
+}
+
+// newsSourcesView is the view model of the news_sources partial.
+type newsSourcesView struct {
+	Rows []sourceRow
+}
+
+// newsSourcesData lists the values the news_sources taglist takes
+// (classes.NewsSources): each article type, then the categories its
+// listed articles name, labelled "<type>: <title>".
+func (c settingsAdminController) newsSourcesData(ctx context.Context) (any, error) {
+	app := appOf(c.app)
+	db, err := database(ctx, c.app)
+	if err != nil {
+		return nil, err
+	}
+	settings, err := classes.LoadSettings(db)
+	if err != nil {
+		return nil, err
+	}
+	var reg *signpost.Registry
+	if app != nil {
+		reg, _ = app.Lookup[*signpost.Registry]()
+	}
+	sources, err := classes.NewsSources(db, reg, models.Text(settings.DefaultLocale))
+	if err != nil {
+		return nil, err
+	}
+	tr := translator(c.app)
+	label := func(key string) string {
+		if reg != nil {
+			if typ, ok := reg.ContentType(key); ok && typ.Label != "" {
+				return Phrase(ctx, tr, typ.Label, nil)
+			}
+		}
+		return key
+	}
+	view := newsSourcesView{}
+	for _, src := range sources {
+		row := sourceRow{Value: src.Value}
+		if src.ID == "" {
+			row.Label = Phrase(ctx, tr, "golem15.sitemap::lang.news.source_type", map[string]string{"type": label(src.Type)})
+		} else {
+			title := src.Title
+			if title == "" {
+				title = src.ID
+			}
+			row.Label = label(src.Type) + ": " + title
+		}
+		view.Rows = append(view.Rows, row)
+	}
+	return view, nil
+}
+
+// filesData is the view of the S1 files partial.
+func (c settingsAdminController) filesData(ctx context.Context) (any, error) {
 	app := appOf(c.app)
 	db, err := database(ctx, c.app)
 	if err != nil {

controllers/settings/_news_sources.htm

@@ -0,0 +1,19 @@
+{{- if .Data.Rows -}}
+<section>
+<h4>{{ trans "golem15.sitemap::lang.news.sources" }}</h4>
+<div class="summer-table-wrap">
+<table class="summer-table">
+<thead><tr><th>{{ trans "golem15.sitemap::lang.news.source_value" }}</th><th>{{ trans "golem15.sitemap::lang.news.source_label" }}</th></tr></thead>
+<tbody>
+{{- range .Data.Rows -}}
+<tr><td><code>{{ .Value }}</code></td><td>{{ .Label }}</td></tr>
+{{- end -}}
+</tbody>
+</table>
+</div>
+</section>
+{{- else -}}
+<div class="summer-callout" role="status">
+<p class="summer-callout__text">{{ trans "golem15.sitemap::lang.news.none" }}</p>
+</div>
+{{- end -}}

lang/en/lang.yaml

@@ -12,6 +12,8 @@ errors:
   html_path: Start the address with / and use a path only, e.g. /mapa-strony.
   page_size: Enter a whole number from 50 to 500.
   lastmod: 'Enter a date as YYYY-MM-DD, e.g. 2026-10-28, or leave it empty.'
+  news_publication: Enter at most 255 characters, without line breaks.
+  news_source: 'Use the values listed under the field: type:<type key> or category:<type key>:<id>.'
 settings:
   label: Sitemaps
   description: XML sitemaps per content type, images, News, IndexNow and the HTML sitemap.
@@ -69,6 +71,12 @@ files:
   index_note: Search engines read the index at :url, and robots.txt points to it. The files are rebuilt after content changes and every night; saving this form rebuilds them now.
   empty: No files yet. They are built within a few minutes after the first save.
   building: Rebuilding now. Reload the page in a minute.
+news:
+  sources: Values for Types and categories
+  source_value: Value
+  source_label: Articles
+  source_type: 'Every article of :type'
+  none: No content type publishes articles yet.
 indexnow:
   key: 'Key: :key, served at :url'
   no_key: A key is generated when you turn IndexNow on and save.

lang/pl/lang.yaml

@@ -12,6 +12,8 @@ errors:
   html_path: Zacznij adres od / i użyj samej ścieżki, np. /mapa-strony.
   page_size: Wpisz liczbę całkowitą od 50 do 500.
   lastmod: 'Wpisz datę w formacie RRRR-MM-DD, np. 2026-10-28, albo zostaw puste.'
+  news_publication: Wpisz najwyżej 255 znaków, bez podziału wiersza.
+  news_source: 'Użyj wartości z listy pod polem: type:<klucz typu> albo category:<klucz typu>:<id>.'
 settings:
   label: Mapy witryny
   description: Mapy XML według typów treści, obrazy, News, IndexNow i mapa HTML.
@@ -69,6 +71,12 @@ files:
   index_note: Wyszukiwarki czytają indeks pod :url, a robots.txt go wskazuje. Pliki są odbudowywane po zmianach treści i co noc; zapisanie tego formularza odbudowuje je od razu.
   empty: Nie ma jeszcze plików. Powstaną w ciągu kilku minut po pierwszym zapisie.
   building: Trwa odbudowa. Odśwież stronę za minutę.
+news:
+  sources: Wartości pola Typy i kategorie
+  source_value: Wartość
+  source_label: Artykuły
+  source_type: 'Wszystkie artykuły: :type'
+  none: Żaden typ treści nie publikuje jeszcze artykułów.
 indexnow:
   key: 'Klucz: :key, udostępniany pod :url'
   no_key: Klucz zostanie wygenerowany po włączeniu IndexNow i zapisie.

models/settings.go

@@ -92,7 +92,7 @@ func (Settings) TableName() string { return "golem15_sitemap_settings" }
 
 // Fillable lists the columns the settings form edits.
 func (Settings) Fillable() []string {
-	return []string{"site_url", "file_size", "extra_urls"}
+	return []string{"site_url", "file_size", "extra_urls", "images_enabled", "news_enabled", "news_publication", "news_sources"}
 }
 
 // Rules is empty: the settings controller runs Validate before a save.
@@ -103,8 +103,13 @@ const (
 	errFileSize  = "golem15.sitemap::lang.errors.file_size"
 	errURLScheme = "golem15.sitemap::lang.errors.url_scheme"
 	errLastmod   = "golem15.sitemap::lang.errors.lastmod"
+	errNewsName  = "golem15.sitemap::lang.errors.news_publication"
+	errNewsSrc   = "golem15.sitemap::lang.errors.news_source"
 )
 
+// MaxNewsPublication is the longest publication name.
+const MaxNewsPublication = 255
+
 // Validate answers every problem Problems finds as a validation error on
 // its field; the settings controller calls it before a save, so the save
 // answers 422 and the row is left as it was.
@@ -140,9 +145,52 @@ func (s Settings) Problems() map[string][]string {
 			out["extra_urls."+strconv.Itoa(i)+".lastmod"] = []string{errLastmod}
 		}
 	}
+	if name := Text(s.NewsPublication); utf8.RuneCountInString(name) > MaxNewsPublication || strings.ContainsFunc(name, unicode.IsControl) {
+		out["news_publication"] = []string{errNewsName}
+	}
+	for _, v := range s.NewsSources.Get() {
+		if !ValidNewsSource(strings.TrimSpace(v)) {
+			out["news_sources"] = []string{errNewsSrc}
+			break
+		}
+	}
 	return out
 }
 
+// The prefixes of the news_sources values (P33-15): type:<type key> and
+// category:<type key>:<id>.
+const (
+	NewsSourceType     = "type:"
+	NewsSourceCategory = "category:"
+)
+
+// ValidNewsSource reports whether v is a news_sources value:
+// type:<type key> or category:<type key>:<id>, each part 1 to 128 letters,
+// digits, '-', '_' or '.'.
+func ValidNewsSource(v string) bool {
+	switch {
+	case strings.HasPrefix(v, NewsSourceType):
+		return validSourcePart(strings.TrimPrefix(v, NewsSourceType))
+	case strings.HasPrefix(v, NewsSourceCategory):
+		rest := strings.TrimPrefix(v, NewsSourceCategory)
+		i := strings.LastIndex(rest, ":")
+		return i > 0 && validSourcePart(rest[:i]) && validSourcePart(rest[i+1:])
+	}
+	return false
+}
+
+func validSourcePart(s string) bool {
+	if s == "" || len(s) > 128 {
+		return false
+	}
+	for _, r := range s {
+		if !(r >= 'a' && r <= 'z' || r >= 'A' && r <= 'Z' || r >= '0' && r <= '9' || r == '-' || r == '_' || r == '.') {
+			return false
+		}
+	}
+	return true
+}
+
 // AllowedFrontendURL reports whether u may be the site address: the empty
 // string, or an absolute http or https URL with a host and without
 // whitespace, control characters, a double quote, <, > or &. The value

models/settings/fields.yaml

@@ -48,3 +48,54 @@ fields:
                     comment: golem15.sitemap::lang.settings.extra_url_lastmod_comment
                     type: text
                     span: right
+
+    images_enabled:
+        label: golem15.sitemap::lang.settings.images_enabled
+        comment: golem15.sitemap::lang.settings.images_enabled_comment
+        type: switch
+        default: true
+        span: full
+        tab: golem15.sitemap::lang.settings.tab_media
+
+    news_enabled:
+        label: golem15.sitemap::lang.settings.news_enabled
+        comment: golem15.sitemap::lang.settings.news_enabled_comment
+        type: switch
+        default: false
+        span: full
+        tab: golem15.sitemap::lang.settings.tab_media
+
+    news_publication:
+        label: golem15.sitemap::lang.settings.news_publication
+        comment: golem15.sitemap::lang.settings.news_publication_comment
+        type: text
+        span: left
+        tab: golem15.sitemap::lang.settings.tab_media
+        trigger:
+            action: hide
+            field: news_enabled
+            condition: unchecked
+
+    # Taglist options are a fixed list, so the article types and their
+    # categories are listed by the news_sources partial below instead.
+    news_sources:
+        label: golem15.sitemap::lang.settings.news_sources
+        comment: golem15.sitemap::lang.settings.news_sources_comment
+        type: taglist
+        mode: array
+        span: right
+        tab: golem15.sitemap::lang.settings.tab_media
+        trigger:
+            action: hide
+            field: news_enabled
+            condition: unchecked
+
+    _news_sources:
+        type: partial
+        path: news_sources
+        span: full
+        tab: golem15.sitemap::lang.settings.tab_media
+        trigger:
+            action: hide
+            field: news_enabled
+            condition: unchecked

routes.go

@@ -35,7 +35,7 @@ const FilesPath = "/_sitemap/files/"
 func (p *Plugin) Routes(r pact.Router) error {
 	r.Get("/sitemap.xml", p.sitemapIndex, "throttle:"+BucketSitemap)
 	r.Get("/_sitemap/files/{file}", p.sitemapFile, "throttle:"+BucketSitemap)
-	r.Where("file", `sitemap-[a-z0-9-]+-[0-9]+\.xml`)
+	r.Where("file", `sitemap-(news|[a-z0-9-]+-[0-9]+)\.xml`)
 	return nil
 }
 
@@ -111,10 +111,22 @@ GROUP BY image_file_no ORDER BY image_file_no`).Scan(&images).Error; err != nil
 		}
 		rows = append(rows, images...)
 	}
-	files := make([]classes.IndexFile, 0, len(rows))
+	files := make([]classes.IndexFile, 0, len(rows)+1)
 	for _, row := range rows {
 		files = append(files, classes.IndexFile{Loc: site + "/" + classes.FileName(row.Grp, row.FileNo), LastMod: row.LastMod})
 	}
+	if settings.NewsEnabled {
+		news, err := classes.NewsEntries(db, p.app, settings, time.Now().UTC())
+		if err != nil {
+			pluginLog.Error("golem15.sitemap: news index", "error", err)
+			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+			return
+		}
+		if len(news) > 0 {
+			newest := news[0].Published
+			files = append(files, classes.IndexFile{Loc: site + "/" + classes.NewsFile, LastMod: &newest})
+		}
+	}
 	var buf bytes.Buffer
 	if err := classes.WriteIndex(&buf, files); err != nil {
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
@@ -127,6 +139,10 @@ GROUP BY image_file_no ORDER BY image_file_no`).Scan(&images).Error; err != nil
 // first seen. An unknown file, or one without a listed address, is a 404.
 // sitemap-images-<n>.xml is an image sitemap file (imageFile).
 func (p *Plugin) sitemapFile(w http.ResponseWriter, r *http.Request) {
+	if r.PathValue("file") == classes.NewsFile {
+		p.newsFile(w, r)
+		return
+	}
 	grp, n, ok := classes.ParseFileName(r.PathValue("file"))
 	if !ok {
 		http.NotFound(w, r)
@@ -223,6 +239,39 @@ func (p *Plugin) imageFile(w http.ResponseWriter, r *http.Request, db *gorm.DB,
 	writeXML(w, buf.Bytes(), true)
 }
 
+// newsFile serves sitemap-news.xml (D-31): the articles of the last two
+// days (classes.NewsEntries). It is a 404 while the News sitemap is off.
+func (p *Plugin) newsFile(w http.ResponseWriter, r *http.Request) {
+	db, err := database(p.app)
+	if err != nil {
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+	db = db.WithContext(r.Context())
+	settings, err := classes.LoadSettings(db)
+	if err != nil {
+		pluginLog.Error("golem15.sitemap: load settings", "error", err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+	if !settings.NewsEnabled || classes.SiteURL(p.app, settings) == "" {
+		http.NotFound(w, r)
+		return
+	}
+	entries, err := classes.NewsEntries(db, p.app, settings, time.Now().UTC())
+	if err != nil {
+		pluginLog.Error("golem15.sitemap: news file", "error", err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+	var buf bytes.Buffer
+	if err := classes.WriteNewsURLSet(&buf, entries); err != nil {
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+	writeXML(w, buf.Bytes(), true)
+}
+
 // writeXML answers 200 with an XML body. A file carries X-Robots-Tag
 // noindex, so search engines read it without indexing it as a page.
 func writeXML(w http.ResponseWriter, body []byte, noindex bool) {

sitemap_extras_test.go

@@ -181,3 +181,112 @@ func TestImageSitemap(t *testing.T) {
 		t.Errorf("image file with the image sitemap off: %d", rec.Code)
 	}
 }
+
+// newsLocs lists the <loc> values of a News sitemap.
+func newsLocs(body string) []string { return locs(body) }
+
+// TestNewsSitemap pins D-31's News sitemap (RESEARCH Pitfall 9): with
+// news_enabled the index lists sitemap-news.xml with the articles first
+// published in the last two days (1 and 47 hours ago, not 49), newest
+// first, never a record of another kind; each with the publication name
+// (news_publication, else app.name), the language of its locale, the
+// publication date and the title; news_sources narrows it to the listed
+// types and categories; more than 1000 candidates list the newest 1000;
+// the settings form refuses a malformed source and lists the values to
+// use; news_enabled off takes the file out of the index and answers 404.
+func TestNewsSitemap(t *testing.T) {
+	e := bootJournal(t)
+	now := time.Now().UTC().Truncate(time.Second)
+	fresh := post(1, "fresh", "pl", now.Add(-time.Hour))
+	fresh.Locales[0].Title = `Grzyby & "huby"`
+	fresh.Parents = []pact.ContentRef{{Type: categoryType, ID: "3"}}
+	contentStore.put(postType, fresh)
+	contentStore.put(postType, post(2, "older", "en", now.Add(-47*time.Hour)))
+	contentStore.put(postType, post(3, "stale", "en", now.Add(-49*time.Hour)))
+	cat := now.Add(-time.Hour)
+	contentStore.put(categoryType, fakeRecord{ID: 3, Published: true, LastMod: cat, PublishedAt: &cat, Locales: []pact.ContentLocale{{Locale: "pl", URL: "/kategoria/lecznicze", Title: "Lecznicze"}}})
+	e.rebuild(t)
+
+	// Off by default: not in the index, the file is a 404.
+	if index := e.get(t, "/sitemap.xml").Body.String(); strings.Contains(index, "sitemap-news.xml") {
+		t.Fatalf("index with the News sitemap off:\n%s", index)
+	}
+	if rec := e.get(t, "/_sitemap/files/sitemap-news.xml"); rec.Code != http.StatusNotFound {
+		t.Fatalf("News file while off: %d", rec.Code)
+	}
+
+	// The settings form: the Images and News tab, a malformed source is
+	// refused, the partial lists the values.
+	token := e.admin(t, permSitemap)
+	const base = "/golem15/sitemap/settings"
+	schema := e.call(t, http.MethodGet, base+"/schema/form", token, nil).Body.String()
+	for _, want := range []string{`"images_enabled"`, `"news_enabled"`, `"news_publication"`, `"news_sources"`, "Images and News"} {
+		if !strings.Contains(schema, want) {
+			t.Errorf("form schema lacks %s", want)
+		}
+	}
+	for _, bad := range []any{[]string{"posts"}, []string{"category:acme-category"}, []string{"type:a b"}} {
+		if rec := e.call(t, http.MethodPut, base+"/1", token, map[string]any{"news_sources": bad}); rec.Code != http.StatusUnprocessableEntity || !strings.Contains(rec.Body.String(), `"news_sources"`) {
+			t.Errorf("news_sources %v: %d %s", bad, rec.Code, rec.Body.String())
+		}
+	}
+	rec := e.call(t, http.MethodGet, base+"/partials/news_sources", token, nil)
+	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), "type:acme-post") || !strings.Contains(rec.Body.String(), "category:acme-category:3") || !strings.Contains(rec.Body.String(), "Categories: Lecznicze") {
+		t.Fatalf("news_sources partial: %d %s", rec.Code, rec.Body.String())
+	}
+	if rec := e.call(t, http.MethodPut, base+"/1", token, map[string]any{"news_enabled": true, "news_sources": []string{}}); rec.Code != http.StatusOK {
+		t.Fatalf("enable News: %d %s", rec.Code, rec.Body.String())
+	}
+
+	index := e.get(t, "/sitemap.xml").Body.String()
+	if !strings.Contains(index, "<loc>https://api.example.test/sitemap-news.xml</loc>") {
+		t.Fatalf("index lacks the News file:\n%s", index)
+	}
+	rec = e.get(t, "/_sitemap/files/sitemap-news.xml")
+	body := rec.Body.String()
+	if rec.Code != http.StatusOK || rec.Header().Get("X-Robots-Tag") != "noindex" || !strings.Contains(body, `xmlns:news="http://www.google.com/schemas/sitemap-news/0.9"`) {
+		t.Fatalf("News file: %d %v\n%s", rec.Code, rec.Header(), body)
+	}
+	if got := newsLocs(body); strings.Join(got, " ") != "https://api.example.test/blog/fresh https://api.example.test/blog/older" {
+		t.Fatalf("News articles = %v\n%s", got, body)
+	}
+	wantFresh := "<url><loc>https://api.example.test/blog/fresh</loc><news:news><news:publication><news:name>sitemap-smoke</news:name><news:language>pl</news:language></news:publication><news:publication_date>" +
+		now.Add(-time.Hour).Format(time.RFC3339) + "</news:publication_date><news:title>Grzyby &amp; &#34;huby&#34;</news:title></news:news></url>"
+	if !strings.Contains(body, wantFresh) {
+		t.Fatalf("News entry of the fresh post:\n%s\nwant %s", body, wantFresh)
+	}
+
+	// The publication name setting and the sources.
+	e.exec(t, `UPDATE golem15_sitemap_settings SET news_publication = 'Gazeta', news_sources = '["category:acme-category:3"]' WHERE id = 1`)
+	body = e.get(t, "/_sitemap/files/sitemap-news.xml").Body.String()
+	if got := newsLocs(body); strings.Join(got, " ") != "https://api.example.test/blog/fresh" || !strings.Contains(body, "<news:name>Gazeta</news:name>") {
+		t.Fatalf("News with a category source = %v\n%s", got, body)
+	}
+	e.exec(t, `UPDATE golem15_sitemap_settings SET news_sources = '["type:acme-post"]' WHERE id = 1`)
+	if got := newsLocs(e.get(t, "/_sitemap/files/sitemap-news.xml").Body.String()); len(got) != 2 {
+		t.Fatalf("News with a type source = %v", got)
+	}
+	e.exec(t, `UPDATE golem15_sitemap_settings SET news_sources = '["type:acme-category"]' WHERE id = 1`)
+	if got := newsLocs(e.get(t, "/_sitemap/files/sitemap-news.xml").Body.String()); len(got) != 0 {
+		t.Fatalf("a collection type in the News sitemap = %v", got)
+	}
+
+	// More than 1000 candidates: the newest 1000.
+	e.exec(t, `UPDATE golem15_sitemap_settings SET news_sources = '[]' WHERE id = 1`)
+	for i := 0; i < 1005; i++ {
+		contentStore.put(postType, post(100+i, fmt.Sprintf("bulk-%d", i), "en", now.Add(-2*time.Hour-time.Duration(i)*time.Minute)))
+	}
+	e.rebuild(t)
+	got := newsLocs(e.get(t, "/_sitemap/files/sitemap-news.xml").Body.String())
+	if len(got) != 1000 || got[0] != "https://api.example.test/blog/fresh" || got[999] != "https://api.example.test/blog/bulk-998" {
+		t.Fatalf("News with 1007 candidates lists %d, first %v last %v", len(got), got[:1], got[len(got)-1:])
+	}
+
+	e.exec(t, `UPDATE golem15_sitemap_settings SET news_enabled = FALSE WHERE id = 1`)
+	if index := e.get(t, "/sitemap.xml").Body.String(); strings.Contains(index, "sitemap-news.xml") {
+		t.Fatalf("index after turning News off:\n%s", index)
+	}
+	if rec := e.get(t, "/_sitemap/files/sitemap-news.xml"); rec.Code != http.StatusNotFound {
+		t.Fatalf("News file after turning it off: %d", rec.Code)
+	}
+}