05/31 Fix yfinance issue

app/services/fx_service.py

@@ -77,17 +77,26 @@ def force_refresh():
 # ── Fetchers ──────────────────────────────────────────────────────────────────
 
 def _fetch_yfinance():
-    """Fetch USDVND=X via yfinance. Most reliable — uses Yahoo Finance forex."""
-    try:
-        import yfinance as yf
-        ticker = yf.Ticker('USDVND=X')
-        hist = ticker.history(period='5d')
-        if not hist.empty:
-            rate = float(hist['Close'].iloc[-1])
-            log.info(f'[fx] yfinance: 1 USD = {rate:,.0f} VND')
-            return rate
-    except Exception as e:
-        log.warning(f'[fx] yfinance failed: {e}')
+    """Fetch USDVND=X via Yahoo Finance v8 chart API (direct HTTP, no yfinance needed)."""
+    for subdomain in ('query1', 'query2'):
+        url = (
+            f'https://{subdomain}.finance.yahoo.com/v8/finance/chart/USDVND=X'
+            '?range=5d&interval=1d&includePrePost=false'
+        )
+        try:
+            resp = requests.get(url, timeout=REQUEST_TIMEOUT,
+                                headers={'User-Agent': 'Mozilla/5.0', 'Accept': 'application/json'})
+            if resp.status_code == 200:
+                result = resp.json().get('chart', {}).get('result')
+                if result:
+                    closes = result[0]['indicators']['quote'][0]['close']
+                    valid = [c for c in closes if c is not None]
+                    if valid:
+                        rate = float(valid[-1])
+                        log.info(f'[fx] Yahoo v8: 1 USD = {rate:,.0f} VND')
+                        return rate
+        except Exception as e:
+            log.warning(f'[fx] Yahoo v8 {subdomain}: {e}')
     return None