feat: verification files API

- GET /_seo/api/v1/verification/{name} serves a verification file stored
  in the SEO settings with its content type, nosniff and a sandboxing CSP
  (D-05, D-103); the name pattern is enforced in the route and the
  lookup, and no route is registered at the site root

classes/verification.go

@@ -0,0 +1,53 @@
+package classes
+
+import (
+	"context"
+	"regexp"
+	"strings"
+)
+
+// VerificationNamePattern is the form of a verification file name (D-05,
+// T-32-21): no slashes, an html, txt or xml extension.
+const VerificationNamePattern = `[A-Za-z0-9._-]+\.(html|txt|xml)`
+
+var verificationName = regexp.MustCompile(`^` + VerificationNamePattern + `$`)
+
+// VerificationFile is one stored search-engine verification file.
+type VerificationFile struct {
+	Name        string
+	Body        string
+	ContentType string
+}
+
+// verificationTypes are the content types per extension.
+var verificationTypes = map[string]string{
+	".html": "text/html; charset=utf-8",
+	".txt":  "text/plain; charset=utf-8",
+	".xml":  "application/xml; charset=utf-8",
+}
+
+// VerificationFileByName returns the verification file stored in the SEO
+// settings under name (D-05, D-103), found false for an unknown or
+// malformed name. The frontend serves it at the site root (Phase 33); the
+// plugin never registers a root route for it.
+func (s *Service) VerificationFileByName(ctx context.Context, name string) (VerificationFile, bool, error) {
+	if !verificationName.MatchString(name) {
+		return VerificationFile{}, false, nil
+	}
+	db, err := s.DB(ctx)
+	if err != nil {
+		return VerificationFile{}, false, err
+	}
+	settings, err := LoadSettings(db)
+	if err != nil {
+		return VerificationFile{}, false, err
+	}
+	for _, f := range settings.Files() {
+		if strings.TrimSpace(f.Filename) != name {
+			continue
+		}
+		ext := name[strings.LastIndex(name, "."):]
+		return VerificationFile{Name: name, Body: f.Body, ContentType: verificationTypes[strings.ToLower(ext)]}, true, nil
+	}
+	return VerificationFile{}, false, nil
+}

controllers/api/verification.go

@@ -0,0 +1,38 @@
+package api
+
+import (
+	"net/http"
+
+	"git.golem15.com/golem15/sm-seo-plugin/classes"
+	"git.golem15.com/golem15/summercms/modules/wire"
+)
+
+// Verification serves GET /_seo/api/v1/verification/{name} (D-05, D-103):
+// the body of a search-engine verification file stored in the SEO
+// settings, with the content type of its extension, for the frontend to
+// serve at the site root. The body is never run: it carries nosniff and a
+// sandboxing Content-Security-Policy. An unknown or malformed name is 404.
+func Verification(service func() *classes.Service) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		svc := service()
+		if svc == nil {
+			wire.WriteJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "SEO is not available"})
+			return
+		}
+		file, found, err := svc.VerificationFileByName(r.Context(), r.PathValue("name"))
+		if err != nil {
+			log.Error("golem15.seo: verification file", "error", err)
+			wire.WriteJSON(w, http.StatusInternalServerError, map[string]string{"error": "Internal Server Error"})
+			return
+		}
+		if !found {
+			wire.WriteJSON(w, http.StatusNotFound, map[string]string{"error": "Not Found"})
+			return
+		}
+		w.Header().Set("Content-Type", file.ContentType)
+		w.Header().Set("X-Content-Type-Options", "nosniff")
+		w.Header().Set("Content-Security-Policy", "default-src 'none'; sandbox")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte(file.Body))
+	}
+}

robots_test.go

@@ -191,3 +191,45 @@ func TestRobotsScreen(t *testing.T) {
 		t.Fatalf("tester context = %s, want the crawler list", body)
 	}
 }
+
+// get runs an anonymous GET.
+func (e *testEnv) get(t *testing.T, path string) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, path, nil)
+	req.RemoteAddr = "198.51.100.11:4000"
+	rec := httptest.NewRecorder()
+	e.h.ServeHTTP(rec, req)
+	return rec
+}
+
+// TestVerificationFile checks the verification-file API (D-05, D-103,
+// T-32-21): a stored file is served with its content type through
+// /_seo/api/v1/verification/{name}; an unknown or malformed name is 404,
+// and nothing is registered at the site root.
+func TestVerificationFile(t *testing.T) {
+	env := bootEnv(t)
+	if err := env.db.Exec(`UPDATE golem15_seo_settings SET verify_files = ? WHERE id = 1`,
+		`[{"filename":"google1234.html","body":"google-site-verification: google1234.html"},{"filename":"BingSiteAuth.xml","body":"<users><user>ABC</user></users>"}]`).Error; err != nil {
+		t.Fatal(err)
+	}
+	rec := env.get(t, "/_seo/api/v1/verification/google1234.html")
+	if rec.Code != http.StatusOK || rec.Body.String() != "google-site-verification: google1234.html" {
+		t.Fatalf("verification file = %d %q, want the stored body", rec.Code, rec.Body.String())
+	}
+	if h := rec.Header(); h.Get("Content-Type") != "text/html; charset=utf-8" || h.Get("X-Content-Type-Options") != "nosniff" || h.Get("X-Robots-Tag") != "noindex" || !strings.Contains(h.Get("Content-Security-Policy"), "sandbox") {
+		t.Fatalf("verification headers = %v", h)
+	}
+	if rec := env.get(t, "/_seo/api/v1/verification/BingSiteAuth.xml"); rec.Code != http.StatusOK || !strings.HasPrefix(rec.Header().Get("Content-Type"), "application/xml") {
+		t.Fatalf("xml verification file = %d %v", rec.Code, rec.Header())
+	}
+	for _, path := range []string{
+		"/_seo/api/v1/verification/missing.html",
+		"/_seo/api/v1/verification/google1234.php",
+		"/_seo/api/v1/verification/..%2Fgoogle1234.html",
+		"/google1234.html",
+	} {
+		if rec := env.get(t, path); rec.Code != http.StatusNotFound {
+			t.Fatalf("GET %s = %d %s, want 404", path, rec.Code, rec.Body.String())
+		}
+	}
+}

routes.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"time"
 
+	"git.golem15.com/golem15/sm-seo-plugin/classes"
 	apicontrollers "git.golem15.com/golem15/sm-seo-plugin/controllers/api"
 	"git.golem15.com/golem15/summercms/modules/pact"
 	"git.golem15.com/golem15/summercms/modules/surf"
@@ -28,6 +29,11 @@ func (p *Plugin) Routes(r pact.Router) error {
 	r.Group("/_seo/api/v1", nil, func(g pact.Router) {
 		g.Get("/resolve", noindex(apicontrollers.Resolve(p.Service)), "throttle:"+BucketResolve)
 		g.Post("/notfound", noindex(apicontrollers.NotFound(p.Service)), "throttle:"+BucketNotFound)
+		// Verification files are served here only; the frontend maps them
+		// at the site root (D-103). A root route would capture every
+		// one-segment page of a site served at GET /.
+		g.Get("/verification/{name}", noindex(apicontrollers.Verification(p.Service)), "throttle:"+BucketResolve)
+		g.Where("name", classes.VerificationNamePattern)
 	})
 	return nil
 }