fix(android): improved cache control interceptor

Author: farfromrefug

packages/https/platforms/android/java/com/nativescript/https/CacheInterceptor.java

@@ -10,10 +10,22 @@ public class CacheInterceptor {
         Request originalRequest = chain.request();
         String cacheControlHeader = originalRequest.header("Cache-Control");
         Response originalResponse = chain.proceed(originalRequest);
-        if (cacheControlHeader != null) {
-            return originalResponse.newBuilder().header("Cache-Control", cacheControlHeader).removeHeader("Pragma").build();
-        } else {
+
+        // Only touch GET responses
+        if (!"GET".equalsIgnoreCase(originalRequest.method())) {
             return originalResponse;
         }
+
+        String respCc = originalResponse.header("Cache-Control");
+        // If server didn't provide caching or forbids it, add a safe fallback
+        if (cacheControlHeader != null && (respCc == null || respCc.isEmpty() || respCc.contains("no-store") || respCc.contains("no-cache"))) {
+            // revalidate on network (max-age=0) but allow stale fallback if error
+            // stale-if-error may not be honored by everything but OkHttp will cache, enabling our fallback
+            return originalResponse.newBuilder()
+                    .removeHeader("Pragma")
+                    .header("Cache-Control", cacheControlHeader)
+                    .build();
+        }
+        return originalResponse;
     };
 }