public string DecryptData(byte[] decryptionKey, EncryptedChannelData encryptedData)
{
string decryptedText = null;
byte[] cipher = null;
byte[] nonce = null;
if (encryptedData != null)
{
if (encryptedData.ciphertext != null)
{
cipher = Convert.FromBase64String(encryptedData.ciphertext);
}
if (encryptedData.nonce != null)
{
nonce = Convert.FromBase64String(encryptedData.nonce);
}
}
if (cipher != null && nonce != null)
{
using (XSalsa20Poly1305 secretBox = new XSalsa20Poly1305(decryptionKey))
{
byte[] decryptedBytes = new byte[cipher.Length - XSalsa20Poly1305.TagLength];
if (secretBox.TryDecrypt(decryptedBytes, cipher, nonce))
{
decryptedText = Encoding.UTF8.GetString(decryptedBytes);
}
else
{
throw new ChannelDecryptionException("Decryption failed for channel.");
}
}
}
else
{
throw new ChannelDecryptionException("Insufficient data received; requires encrypted data with 'ciphertext' and 'nonce'.");
}
return(decryptedText);
}
private void WebsocketMessageReceived(object sender, MessageReceivedEventArgs e)
{
string eventName = null;
string channelName = null;
try
{
if (_pusher.PusherOptions.TraceLogger != null)
{
_pusher.PusherOptions.TraceLogger.TraceInformation($"Websocket message received:{Environment.NewLine}{e.Message}");
}
JObject jObject = JObject.Parse(e.Message);
string rawJson = jObject.ToString(Formatting.None);
Dictionary <string, object> message = GetEventPropertiesFromMessage(rawJson);
if (message.ContainsKey("event"))
{
eventName = (string)message["event"];
if (eventName == Constants.ERROR)
{
/*
* Errors are in a different Json form to other messages.
* The data property is an object and not a string and needs to be dealt with differently; for example:
* {"event":"pusher:error","data":{"code":4001,"message":"App key Invalid not in this cluster. Did you forget to specify the cluster?"}}
*/
ParseError(jObject["data"]);
}
else
{
/*
* For messages other than "pusher:error" the data property is a string; for example:
* {
* "event": "pusher:connection_established",
* "data": "{\"socket_id\":\"131160.155806628\"}"
* }
*
* {
* "event": "pusher_internal:subscription_succeeded",
* "data": "{\"presence\":{\"count\":1,\"ids\":[\"131160.155806628\"],\"hash\":{\"131160.155806628\":{\"name\":\"user-1\"}}}}",
* "channel": "presence-channel-1"
* }
*/
string messageData = string.Empty;
if (message.ContainsKey("data"))
{
messageData = (string)message["data"];
}
if (message.ContainsKey("channel"))
{
channelName = (string)message["channel"];
if (!ProcessPusherChannelEvent(eventName, channelName, messageData))
{
byte[] decryptionKey = _pusher.GetSharedSecret(channelName);
if (decryptionKey != null)
{
message["data"] = _dataDecrypter.DecryptData(decryptionKey, EncryptedChannelData.CreateFromJson(messageData));
}
EmitEvent(eventName, rawJson, message);
EmitChannelEvent(eventName, rawJson, channelName, message);
}
}
else
{
ProcessPusherEvent(eventName, messageData);
}
}
}
}
catch (Exception exception)
{
string operation = nameof(WebsocketMessageReceived);
PusherException error;
if (channelName != null)
{
if (exception is ChannelException channelException)
{
channelException.ChannelName = channelName;
channelException.EventName = eventName;
channelException.SocketID = SocketId;
error = channelException;
}
else
{
error = new ChannelException($"An unexpected error was detected when performing the operation '{operation}'", ErrorCodes.MessageReceivedError, channelName, SocketId, exception)
{
EventName = eventName,
};
}
}
else
{
if (eventName != null)
{
operation += $" for event '{eventName}'";
}
error = new OperationException(ErrorCodes.MessageReceivedError, operation, exception);
}
RaiseError(error);
}
}
