fix #29 remove duplicated slashes

lib/common/link_helper.dart

@@ -18,6 +18,40 @@ class LinkHelper {
     return links.first.text;
   }
 
+  static String removeDuplicateSlashes(String url) {
+    // Split the URL into components
+    Uri uri = Uri.parse(url);
+
+    // Get the scheme (e.g., https://)
+    String scheme = uri.scheme;
+
+    // Get the authority (e.g., www.baidu.com)
+    String authority = uri.authority;
+
+    // Get the path (e.g., /path/to/resource)
+    String path = uri.path.replaceAll(RegExp(r'/{2,}'), '/');
+
+    // Get the query (e.g., ?hello)
+    String query = uri.query;
+
+    // Get the fragment (e.g., #anchor)
+    String fragment = uri.fragment;
+
+    // Construct the new URL with no duplicated slashes
+    String newUrl = '$scheme://$authority$path';
+
+    // Append the query if it exists
+    if (query.isNotEmpty) {
+      newUrl += '?$query';
+    }
+
+    // Append the fragment if it exists
+    if (fragment.isNotEmpty) {
+      newUrl += '#$fragment';
+    }
+
+    return newUrl;
+  }
 
  static getSubscriptionUrl(Radar radar) async {
    Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
@@ -27,6 +61,7 @@ class LinkHelper {
      host = prefs.getString("RSSHUB")!;
    }
    var url = "$host${radar.path}";
+   url = removeDuplicateSlashes(url);
    if (!radar.isRssHub) {
      url = radar.path!;
    }