Fix handling of public shares

MegaApiClient/MegaApiClient.cs

@@ -1112,7 +1112,7 @@ private TResponse RequestCore<TResponse>(RequestBase request, byte[] key)
         where TResponse : class
     {
       var dataRequest = JsonConvert.SerializeObject(new object[] { request });
-      var uri = GenerateUrl(request.QueryArguments);
+      var uri = GenerateUrl(request.QueryArguments, request.UseSession);
       object jsonData = null;
       var attempt = 0;
       var apiCode = ApiResultCode.Ok;
@@ -1182,15 +1182,15 @@ private void Wait(TimeSpan retryDelay)
 #endif
     }
 
-    private Uri GenerateUrl(Dictionary<string, string> queryArguments)
+    private Uri GenerateUrl(Dictionary<string, string> queryArguments, bool useSession = true)
     {
       var query = new Dictionary<string, string>(queryArguments)
       {
         ["id"] = (_sequenceIndex++ % uint.MaxValue).ToString(CultureInfo.InvariantCulture),
         ["ak"] = _options.ApplicationKey
       };
 
-      if (!string.IsNullOrEmpty(_sessionId))
+      if (useSession && !string.IsNullOrEmpty(_sessionId))
       {
         query["sid"] = _sessionId;
       }

MegaApiClient/Node.cs

@@ -136,54 +136,72 @@ public void OnDeserialized(StreamingContext ctx)
           return;
         }
 
-        // There are cases where the SerializedKey property contains multiple keys separated with /
-        // This can occur when a folder is shared and the parent is shared too.
-        // Both keys are working so we use the first one
-        var serializedKey = SerializedKey.Split('/')[0];
-        var splitPosition = serializedKey.IndexOf(":", StringComparison.Ordinal);
-        var encryptedKey = serializedKey.Substring(splitPosition + 1).FromBase64();
-
-        // If node is shared, we need to retrieve shared masterkey
-        if (_sharedKeys != null)
+        // The SerializedKey property can contain multiple keys separated with /
+        // This occurs when a folder is shared and the parent is shared too, or for
+        // shared folder links where the owner's key and share key are both present.
+        // Try each key and use the first one that produces valid attributes.
+        var serializedKeys = SerializedKey.Split('/');
+
+        foreach (var serializedKey in serializedKeys)
         {
+          var splitPosition = serializedKey.IndexOf(":", StringComparison.Ordinal);
+          if (splitPosition < 0)
+          {
+            continue;
+          }
+
           var handle = serializedKey.Substring(0, splitPosition);
-          var sharedKey = _sharedKeys.FirstOrDefault(x => x.Id == handle);
-          if (sharedKey != null)
+          var encryptedKey = serializedKey.Substring(splitPosition + 1).FromBase64();
+
+          // If node is shared, we need to retrieve shared masterkey
+          var usedMasterKey = _masterKey;
+          byte[] sharedKeyValue = null;
+          if (_sharedKeys != null)
           {
-            _masterKey = Crypto.DecryptKey(sharedKey.Key.FromBase64(), _masterKey);
-            if (Type == NodeType.Directory)
-            {
-              SharedKey = _masterKey;
-            }
-            else
+            var sharedKey = _sharedKeys.FirstOrDefault(x => x.Id == handle);
+            if (sharedKey != null)
             {
-              SharedKey = Crypto.DecryptKey(encryptedKey, _masterKey);
+              usedMasterKey = Crypto.DecryptKey(sharedKey.Key.FromBase64(), _masterKey);
+              sharedKeyValue = Type == NodeType.Directory
+                ? usedMasterKey
+                : Crypto.DecryptKey(encryptedKey, usedMasterKey);
             }
           }
-        }
 
-        if (encryptedKey.Length != 16 && encryptedKey.Length != 32)
-        {
-          // Invalid key size
-          return;
-        }
+          if (encryptedKey.Length != 16 && encryptedKey.Length != 32)
+          {
+            continue;
+          }
 
-        FullKey = Crypto.DecryptKey(encryptedKey, _masterKey);
+          var fullKey = Crypto.DecryptKey(encryptedKey, usedMasterKey);
+          byte[] nodeKey;
+          byte[] iv = null;
+          byte[] metaMac = null;
 
-        if (Type == NodeType.File)
-        {
-          Crypto.GetPartsFromDecryptedKey(FullKey, out var iv, out var metaMac, out var fileKey);
+          if (Type == NodeType.File)
+          {
+            Crypto.GetPartsFromDecryptedKey(fullKey, out iv, out metaMac, out nodeKey);
+          }
+          else
+          {
+            nodeKey = fullKey;
+          }
+
+          var attrs = Crypto.DecryptAttributes(SerializedAttributes.FromBase64(), nodeKey);
 
+          FullKey = fullKey;
+          Key = nodeKey;
           Iv = iv;
           MetaMac = metaMac;
-          Key = fileKey;
-        }
-        else
-        {
-          Key = FullKey;
+          SharedKey = sharedKeyValue;
+          Attributes = attrs;
+
+          if (attrs?.Name != null && !attrs.Name.StartsWith("Attribute deserialization failed"))
+          {
+            break;
+          }
         }
 
-        Attributes = Crypto.DecryptAttributes(SerializedAttributes.FromBase64(), Key);
         FileAttributes = DeserializeFileAttributes(SerializedFileAttributes);
       }
     }
@@ -278,12 +296,12 @@ private bool IsShareRoot
         {
           return true;
         }
-        else
+
+        return _node.SerializedKey.Split('/').Any(key =>
         {
-          var serializedKey = _node.SerializedKey.Split('/')[0];
-          var splitPosition = serializedKey.IndexOf(":", StringComparison.Ordinal);
-          return serializedKey.Substring(0, splitPosition) == Id;
-        }
+          var splitPosition = key.IndexOf(":", StringComparison.Ordinal);
+          return splitPosition >= 0 && key.Substring(0, splitPosition) == Id;
+        });
       }
     }
   }

MegaApiClient/Serialization/DownloadUrl.cs

@@ -12,6 +12,7 @@ public DownloadUrlRequest(INode node)
       if (node is PublicNode publicNode)
       {
         QueryArguments["n"] = publicNode.ShareId;
+        UseSession = false;
       }
     }
 

MegaApiClient/Serialization/GetNodes.cs

@@ -12,6 +12,8 @@ public GetNodesRequest(string shareId = null)
       : base("f")
     {
       C = 1;
+      Ca = 1;
+      UseSession = false;
 
       if (shareId != null)
       {
@@ -27,6 +29,9 @@ public GetNodesRequest(string shareId = null)
 
     [JsonProperty("r")]
     public int R { get; private set; }
+
+    [JsonProperty("ca")]
+    public int Ca { get; private set; }
   }
 
   internal class GetNodesResponse

MegaApiClient/Serialization/RequestBase.cs

@@ -9,12 +9,16 @@ protected RequestBase(string action)
     {
       Action = action;
       QueryArguments = new Dictionary<string, string>();
+      UseSession = true;
     }
 
     [JsonProperty("a")]
     public string Action { get; private set; }
 
     [JsonIgnore]
     public Dictionary<string, string> QueryArguments { get; }
+
+    [JsonIgnore]
+    public bool UseSession { get; protected set; }
   }
 }