二次开发源码提交

2026-05-15 08:52:48 +08:00
parent 4131f7321a
commit eb35a1d067
191 changed files with 34566 additions and 0 deletions
@@ -0,0 +1,86 @@
+/// Cloudreve obfuscated thumbnail URL decoder.
+/// Ported from the Go reference implementation in the API documentation.
+class TimeFlowDecoder {
+  /// Decode an obfuscated time-flow string.
+  /// Tries current time, then ±1000ms to account for clock drift.
+  /// Returns null if all attempts fail.
+  static String? decodeTimeFlowString(String str) {
+    if (str.isEmpty) return null;
+
+    final timeNow = DateTime.now().millisecondsSinceEpoch;
+
+    for (final offset in [0, -1000, 1000]) {
+      final result = _decodeTimeFlowStringTime(str, timeNow + offset);
+      if (result != null) return result;
+    }
+
+    return null;
+  }
+
+  static String? _decodeTimeFlowStringTime(String str, int timeNowMillis) {
+    if (str.isEmpty) return null;
+
+    int timeNow = timeNowMillis ~/ 1000;
+    final timeNowBackup = timeNow;
+
+    final timeDigits = <int>[];
+    if (timeNow == 0) {
+      timeDigits.add(0);
+    } else {
+      int tempTime = timeNow;
+      while (tempTime > 0) {
+        timeDigits.add(tempTime % 10);
+        tempTime = tempTime ~/ 10;
+      }
+    }
+
+    final res = str.split('');
+    var secret = str.split('');
+
+    var add = secret.length % 2 == 0;
+    var timeDigitIndex = (secret.length - 1) % timeDigits.length;
+    final l = secret.length;
+
+    for (int pos = 0; pos < l; pos++) {
+      final targetIndex = l - 1 - pos;
+
+      int newIndex = targetIndex;
+      if (add) {
+        newIndex += timeDigits[timeDigitIndex] * timeDigitIndex;
+      } else {
+        newIndex = 2 * timeDigitIndex * timeDigits[timeDigitIndex] - newIndex;
+      }
+
+      if (newIndex < 0) {
+        newIndex = newIndex.abs();
+      }
+
+      newIndex = newIndex % secret.length;
+
+      res[targetIndex] = secret[newIndex];
+
+      // Swap secret[newIndex] with last element, then shrink
+      final lastSecretIndex = secret.length - 1;
+      final a = secret[lastSecretIndex];
+      final b = secret[newIndex];
+      secret[newIndex] = a;
+      secret[lastSecretIndex] = b;
+      secret = secret.sublist(0, lastSecretIndex);
+
+      add = !add;
+      timeDigitIndex--;
+      if (timeDigitIndex < 0) {
+        timeDigitIndex = timeDigits.length - 1;
+      }
+    }
+
+    final resStr = res.join('');
+    final pipeIndex = resStr.indexOf('|');
+    if (pipeIndex < 0) return null;
+
+    final timestampPart = resStr.substring(0, pipeIndex);
+    if (timestampPart != timeNowBackup.toString()) return null;
+
+    return resStr.substring(pipeIndex + 1);
+  }
+}