feat: configure Redis URL via UI settings

- Add redis_url to SQLite settings table (persisted across restarts)
- On startup, prefer DB-stored URL over REDIS_URL env var
- Add reconnect_redis() to support live URL changes without restart
- Settings API now accepts/returns redis_url field
- Cache tab shows editable URL input with save button and connection status
- Immediate feedback: shows Connected/Disconnected after save

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/app/api/routes.py

@@ -12,7 +12,7 @@ from app.search import search, get_autocomplete
 from app.engines import registry
 from app.excluded import get_excluded_domains, add_excluded_domain, remove_excluded_domain
 from app.settings import get_all_settings, get_setting, set_setting
-from app.cache import is_cache_available, flush_cache
+from app.cache import is_cache_available, flush_cache, reconnect_redis
 
 router = APIRouter()
 
@@ -236,10 +236,12 @@ async def api_remove_excluded_domain(domain: str):
 class SettingsResponse(BaseModel):
     cache_ttl_hours: float = Field(description="Cache TTL in hours (0 = disabled, max 168 = 1 week)")
     cache_available: bool = Field(description="Whether Redis is connected and available")
+    redis_url: str = Field(default="", description="Redis connection URL (e.g. redis://localhost:6379)")
 
 
 class UpdateSettingsRequest(BaseModel):
-    cache_ttl_hours: float = Field(ge=0, le=168, description="Cache TTL in hours (0 = disabled, max 168 = 1 week)")
+    cache_ttl_hours: float | None = Field(default=None, ge=0, le=168, description="Cache TTL in hours (0 = disabled, max 168 = 1 week)")
+    redis_url: str | None = Field(default=None, description="Redis connection URL (empty string to disconnect)")
 
 
 @router.get(
@@ -260,6 +262,7 @@ async def api_get_settings():
     return SettingsResponse(
         cache_ttl_hours=float(settings.get("cache_ttl_hours", "6")),
         cache_available=is_cache_available(),
+        redis_url=settings.get("redis_url", ""),
     )
 
 
@@ -279,10 +282,16 @@ curl -X PUT '$BASE_URL/api/settings' \\
     tags=["Settings"],
 )
 async def api_update_settings(body: UpdateSettingsRequest):
-    set_setting("cache_ttl_hours", str(body.cache_ttl_hours))
+    if body.cache_ttl_hours is not None:
+        set_setting("cache_ttl_hours", str(body.cache_ttl_hours))
+    if body.redis_url is not None:
+        set_setting("redis_url", body.redis_url)
+        await reconnect_redis(body.redis_url)
+    settings = get_all_settings()
     return SettingsResponse(
-        cache_ttl_hours=body.cache_ttl_hours,
+        cache_ttl_hours=float(settings.get("cache_ttl_hours", "6")),
         cache_available=is_cache_available(),
+        redis_url=settings.get("redis_url", ""),
     )
 
 

backend/app/cache.py

@@ -22,11 +22,25 @@ _available: bool = False
 
 
 async def init_redis() -> None:
-    """Try to connect to Redis. If it fails, caching is silently disabled."""
+    """Try to connect to Redis using DB setting first, then env var fallback."""
+    from app.settings import get_setting
+    url = get_setting("redis_url") or os.environ.get("REDIS_URL", "")
+    await reconnect_redis(url)
+
+
+async def reconnect_redis(url: str) -> None:
+    """Connect (or reconnect) to Redis at the given URL."""
     global _redis, _available
-    url = os.environ.get("REDIS_URL", "")
+    # Close existing connection first
+    if _redis:
+        try:
+            await _redis.aclose()
+        except Exception:
+            pass
+        _redis = None
+        _available = False
     if not url:
-        logger.info("REDIS_URL not set — caching disabled")
+        logger.info("Redis URL not set — caching disabled")
         return
     try:
         _redis = aioredis.from_url(url, decode_responses=True, socket_connect_timeout=3)

backend/app/settings.py

@@ -11,6 +11,7 @@ logger = logging.getLogger(__name__)
 # Default values
 DEFAULTS: dict[str, str] = {
     "cache_ttl_hours": "6",
+    "redis_url": "",
 }
 
 

frontend/src/components/SettingsModal.tsx

@@ -246,12 +246,16 @@ function CacheTab() {
   const [flushing, setFlushing] = useState(false);
   const [flushMsg, setFlushMsg] = useState("");
   const [ttl, setTtl] = useState(6);
+  const [redisUrl, setRedisUrl] = useState("");
+  const [urlSaving, setUrlSaving] = useState(false);
+  const [urlMsg, setUrlMsg] = useState("");
 
   useEffect(() => {
     getSettings()
       .then((s) => {
         setSettings(s);
         setTtl(s.cache_ttl_hours);
+        setRedisUrl(s.redis_url);
       })
       .finally(() => setLoading(false));
   }, []);
@@ -269,6 +273,20 @@ function CacheTab() {
     }
   };
 
+  const handleUrlSave = async () => {
+    setUrlSaving(true);
+    setUrlMsg("");
+    try {
+      const updated = await updateSettings({ redis_url: redisUrl.trim() });
+      setSettings(updated);
+      setUrlMsg(updated.cache_available ? "Connected ✓" : redisUrl.trim() ? "Connection failed" : "Disconnected");
+    } catch {
+      setUrlMsg("Failed to save");
+    } finally {
+      setUrlSaving(false);
+    }
+  };
+
   const handleFlush = async () => {
     setFlushing(true);
     setFlushMsg("");
@@ -286,22 +304,46 @@ function CacheTab() {
 
   return (
     <div className="space-y-5">
+      {/* Redis URL configuration */}
       <div>
         <div className="flex items-center gap-2 mb-1">
           <Database className="h-4 w-4 text-muted-foreground" aria-hidden="true" />
-          <p className="text-sm font-medium">Redis Cache</p>
+          <p className="text-sm font-medium">Redis Connection</p>
         </div>
-        <p className="text-sm text-muted-foreground mb-3">
-          {settings?.cache_available
-            ? "Redis is connected. Repeated searches are served from cache."
-            : "Redis is not configured. Set REDIS_URL to enable caching."}
+        <p className="text-xs text-muted-foreground mb-2">
+          Enter a Redis URL to enable search result caching (e.g. redis://localhost:6379).
         </p>
-        <div className={cn("rounded-lg border p-1 inline-flex items-center", !settings?.cache_available && "opacity-50 pointer-events-none")}>
+        <div className="flex gap-2">
+          <input
+            type="url"
+            value={redisUrl}
+            onChange={(e) => { setRedisUrl(e.target.value); setUrlMsg(""); }}
+            onKeyDown={(e) => { if (e.key === "Enter") handleUrlSave(); }}
+            placeholder="redis://host:port"
+            className="flex-1 rounded-lg border bg-background px-3 py-2 text-sm focus-visible:ring-2 focus-visible:ring-ring focus-visible:outline-none"
+            aria-label="Redis URL"
+          />
+          <button
+            onClick={handleUrlSave}
+            disabled={urlSaving}
+            className="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-primary-foreground hover:bg-primary/90 disabled:opacity-50 focus-visible:ring-2 focus-visible:ring-ring focus-visible:outline-none"
+          >
+            {urlSaving ? "Saving…" : "Save"}
+          </button>
+        </div>
+        <div className="flex items-center gap-2 mt-2">
           <span className={cn(
-            "inline-block h-2 w-2 rounded-full mr-2 ml-1",
+            "inline-block h-2 w-2 rounded-full",
             settings?.cache_available ? "bg-green-500" : "bg-muted-foreground"
           )} />
-          <span className="text-xs text-muted-foreground mr-2">{settings?.cache_available ? "Connected" : "Disconnected"}</span>
+          <span className="text-xs text-muted-foreground">
+            {settings?.cache_available ? "Connected" : "Disconnected"}
+          </span>
+          {urlMsg && (
+            <span className={cn("text-xs font-medium", urlMsg.includes("✓") ? "text-green-600 dark:text-green-400" : urlMsg === "Disconnected" ? "text-muted-foreground" : "text-destructive")}>
+              — {urlMsg}
+            </span>
+          )}
         </div>
       </div>
 

frontend/src/lib/api.ts

@@ -146,6 +146,7 @@ export async function removeExcludedDomain(domain: string): Promise<string[]> {
 export interface AppSettings {
   cache_ttl_hours: number;
   cache_available: boolean;
+  redis_url: string;
 }
 
 export async function getSettings(): Promise<AppSettings> {
@@ -154,7 +155,7 @@ export async function getSettings(): Promise<AppSettings> {
   return resp.json();
 }
 
-export async function updateSettings(settings: { cache_ttl_hours: number }): Promise<AppSettings> {
+export async function updateSettings(settings: { cache_ttl_hours?: number; redis_url?: string }): Promise<AppSettings> {
   const resp = await fetch(`${API_BASE}/settings`, {
     method: "PUT",
     headers: { "Content-Type": "application/json" },