xuy-UID2-4848-improve-clouddownload-logging #387 (#388)

* xuy-UID2-4848-improve-clouddownload-logging #387

Author: clarkxuyang

src/main/java/com/uid2/shared/cloud/URLStorageWithMetadata.java

@@ -1,6 +1,7 @@
 package com.uid2.shared.cloud;
 
 import java.io.InputStream;
+import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.Proxy;
 import java.net.URL;
@@ -35,15 +36,30 @@ public void upload(InputStream input, String cloudPath) throws CloudStorageExcep
     public InputStream download(String cloudPath) throws CloudStorageException {
         try {
             URL url = new URL(cloudPath);
-
+            HttpURLConnection httpConn;
+            
             if (this.proxy != null) {
-                return url.openConnection(proxy).getInputStream();
+                httpConn = (HttpURLConnection) url.openConnection(proxy);
+            } else {
+                httpConn = (HttpURLConnection) url.openConnection();
+            }
+            
+            int responseCode = httpConn.getResponseCode();
+            if (responseCode >= 200 && responseCode < 300) {
+                return httpConn.getInputStream();
             } else {
-                return url.openStream();
+                throw new CloudStorageException("Cannot download required files, HTTP response code " + responseCode 
+                + ", please visit UID2 guides for more details");
             }
-        } catch (Throwable t) {
-            // Do not log the message or the original exception as that may contain the pre-signed url
-            throw new CloudStorageException("url download error: " + t.getClass().getSimpleName());
+        }
+        catch (CloudStorageException e) {
+            // Directly rethrow without wrapping again
+            throw e;
+        } 
+        catch (Throwable t) {
+            // Do not log the original exception as it may contain sensitive information such as the pre-signed URL
+            throw new CloudStorageException("Cannot download required files, exception: " + t.getClass().getSimpleName() +
+                ", please visit UID2 guides for more details");
         }
     }