feat(sdkserver): add /api/gachabase/fetch proxy endpoint for Gachabase integration

internal/sdkserver/api.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os"
 	"sync"
+	"time"
 
 	"gac-hkrpg-go/internal/common"
 )
@@ -42,6 +43,7 @@ func registerAPIRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("/api/avatar/rank", corsWrapper(apiAvatarRank))
 	mux.HandleFunc("/api/avatar/max_all", corsWrapper(apiMaxAll))
 	mux.HandleFunc("/api/teleport", corsWrapper(apiTeleport))
+	mux.HandleFunc("/api/gachabase/fetch", corsWrapper(apiGachabaseFetch))
 }
 
 func apiRoot(w http.ResponseWriter, r *http.Request) {
@@ -506,3 +508,63 @@ func apiTeleport(w http.ResponseWriter, r *http.Request) {
 	data.SavePersistent()
 	writeJSON(w, map[string]any{"message": "teleported successfully", "status": 200})
 }
+
+// apiGachabaseFetch proxies requests to hsr.gachabase.net to bypass browser CORS restrictions.
+func apiGachabaseFetch(w http.ResponseWriter, r *http.Request) {
+	targetURL := r.URL.Query().Get("url")
+	targetType := r.URL.Query().Get("type") // "character" | "lightcone" | "relic"
+	targetID := r.URL.Query().Get("id")
+	branch := r.URL.Query().Get("branch")
+	if branch == "" {
+		branch = "beta"
+	}
+	lang := r.URL.Query().Get("lang")
+	if lang == "" {
+		lang = "en"
+	}
+
+	if targetURL == "" && targetID != "" && targetType != "" {
+		switch targetType {
+		case "character", "avatar":
+			targetURL = fmt.Sprintf("https://hsr.gachabase.net/characters/%s/slug/%s?lang=%s", targetID, branch, lang)
+		case "lightcone", "lc":
+			targetURL = fmt.Sprintf("https://hsr.gachabase.net/lightcones/%s/slug/%s?lang=%s", targetID, branch, lang)
+		case "relic":
+			targetURL = fmt.Sprintf("https://hsr.gachabase.net/relics/%s/slug/%s?lang=%s", targetID, branch, lang)
+		}
+	}
+
+	if targetURL == "" {
+		writeJSON(w, map[string]any{"error": "missing url or id/type parameters", "status": 400})
+		return
+	}
+
+	client := &http.Client{Timeout: 12 * time.Second}
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, targetURL, nil)
+	if err != nil {
+		writeJSON(w, map[string]any{"error": err.Error(), "status": 500})
+		return
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36")
+	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		writeJSON(w, map[string]any{"error": "failed to connect to gachabase: " + err.Error(), "status": 502})
+		return
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		writeJSON(w, map[string]any{"error": "failed to read gachabase response: " + err.Error(), "status": 500})
+		return
+	}
+
+	writeJSON(w, map[string]any{
+		"status": resp.StatusCode,
+		"html":   string(body),
+		"url":    targetURL,
+	})
+}
+