Answer IMVU's product REST API for community products

Trying a product on in the shop asks api.imvu.com/product/product-<id>/uml_products for related
products; the guard refused it for T5 products, and the client showed an error. Community products
now get an empty list (and not found for anything else) from the proxy.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

internal/products/intercept.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/url"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -33,6 +34,14 @@ func (p *Products) Intercept(x *proxy.Exchange) error {
 	if host == "api.imvu.com" && participantPath.MatchString(path) {
 		return p.interceptParticipant(x)
 	}
+	if host == "api.imvu.com" {
+		if m := productPath.FindStringSubmatch(path); m != nil {
+			if id, ok := parseID(m[1]); ok && IsCommunity(id) {
+				x.Response = productAPIAnswer(path, m[2])
+				return nil
+			}
+		}
+	}
 	switch path {
 	case "/api/xmlrpc/chat.php":
 		return p.interceptChat(x)
@@ -59,6 +68,21 @@ func (p *Products) Intercept(x *proxy.Exchange) error {
 	return nil
 }
 
+// productPath is IMVU's REST API for a product (api.imvu.com/product/product-<id>[/<relation>]).
+var productPath = regexp.MustCompile(`^/product/product-([0-9.]+)(/[a-z_]+)?$`)
+
+// productAPIAnswer answers the REST API about a community product: no related products (uml_products, which the
+// shop's recommender asks for when a product is tried on), and nothing else.
+func productAPIAnswer(path, relation string) *http.Response {
+	id := "https://api.imvu.com" + path
+	if relation == "/uml_products" {
+		b, _ := json.Marshal(map[string]any{"status": "success", "id": id, "denormalized": map[string]any{
+			id: map[string]any{"data": map[string]any{"total_count": 0, "items": []any{}}, "relations": map[string]any{}}}})
+		return localResponse(200, "application/json", b)
+	}
+	return localResponse(404, "application/json", []byte(`{"status":"failure","error":"NOT_FOUND"}`))
+}
+
 func (p *Products) interceptXMLRPC(x *proxy.Exchange) error {
 	call, err := xmlrpc.ParseCall(x.Body)
 	if err != nil {