Redirect CamelCase /fun/ URLs to space-separated forms

Author: pierres

internal/ui/fundetail/handler.go

@@ -5,6 +5,7 @@ import (
 	"net/url"
 	"sort"
 	"strings"
+	"unicode"
 
 	"pkgstatsd/internal/chartdata"
 	"pkgstatsd/internal/packages"
@@ -35,6 +36,12 @@ func (h *Handler) HandleFunDetail(w http.ResponseWriter, r *http.Request) {
 
 	category := fun.FindCategory(categoryName)
 	if category == nil {
+		if expanded := expandCamelCase(categoryName); expanded != categoryName {
+			if fun.FindCategory(expanded) != nil {
+				http.Redirect(w, r, "/fun/"+url.PathEscape(expanded)+"/"+preset, http.StatusMovedPermanently)
+				return
+			}
+		}
 		http.NotFound(w, r)
 		return
 	}
@@ -139,6 +146,17 @@ func compareURLFromDatasets(datasets []chartdata.Dataset) string {
 	return "/packages?compare=" + strings.Join(names, ",")
 }
 
+func expandCamelCase(s string) string {
+	var b strings.Builder
+	for i, r := range s {
+		if i > 0 && unicode.IsUpper(r) {
+			b.WriteByte(' ')
+		}
+		b.WriteRune(r)
+	}
+	return b.String()
+}
+
 func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("GET /fun/{category}/{preset}", h.HandleFunDetail)
 }

internal/ui/fundetail/handler_test.go

@@ -198,6 +198,40 @@ func TestHandleHistory_CompareURLIncludesAllPackages(t *testing.T) {
 	}
 }
 
+func TestHandleFunDetail_CamelCaseRedirect(t *testing.T) {
+	manifest, _ := layout.NewManifest([]byte(`{}`))
+	handler := NewHandler(nil, manifest)
+
+	tests := []struct {
+		input    string
+		location string
+	}{
+		{"DesktopEnvironments", "/fun/Desktop%20Environments/current"},
+		{"WindowManagers", "/fun/Window%20Managers/history"},
+		{"TerminalEmulators", "/fun/Terminal%20Emulators/current"},
+	}
+
+	for _, tt := range tests {
+		preset := "current"
+		if strings.Contains(tt.location, "history") {
+			preset = "history"
+		}
+		req := httptest.NewRequest(http.MethodGet, "/fun/"+tt.input+"/"+preset, nil)
+		req.SetPathValue("category", tt.input)
+		req.SetPathValue("preset", preset)
+		rr := httptest.NewRecorder()
+
+		handler.HandleFunDetail(rr, req)
+
+		if rr.Code != http.StatusMovedPermanently {
+			t.Errorf("%s: expected 301, got %d", tt.input, rr.Code)
+		}
+		if got := rr.Header().Get("Location"); got != tt.location {
+			t.Errorf("%s: expected Location %q, got %q", tt.input, tt.location, got)
+		}
+	}
+}
+
 func TestHandleFunDetail_InvalidCategory(t *testing.T) {
 	manifest, _ := layout.NewManifest([]byte(`{}`))
 	handler := NewHandler(nil, manifest)