Using domain name instead of IP address for BlueBox

Post here your questions about the C++ API for SFS2X

Moderators: Lapo, Bax, MBagnati

dhuang11
Posts: 38
Joined: 02 May 2014, 08:21

Using domain name instead of IP address for BlueBox

Postby dhuang11 » 27 Jun 2014, 08:35

Using the latest (1.1.2) SFS2X C++, we are able to connect using TCP and UDP by configuring a DNS resolvable hostname. This all seems to work really well as the hostname is properly resolved to an IP address.

We tried to test on BlueBox today and could not get it to connect. After spending a lot of time stepping/debugging through the SFS2X C++ source code, we found that BlueBox connectivity attempts to use the host/IP address directly without attempting to first resolve a potential DNS to IP address as it does when connecting via TCP. It attempts to use the host name directly as an IP address which will cause an exception to be thrown in this code:

Code: Select all

void SFSWebClient::UploadValuesAsync (boost::shared_ptr<string> uriHost, unsigned short int uriPort, boost::shared_ptr<string> paramName, boost::shared_ptr<string> encodedData)
{
   boost::shared_ptr<TCPClient> client = boost::shared_ptr<TCPClient>();

   try {
      client = boost::shared_ptr<TCPClient>(new TCPClient(boostIoService));

      boost::shared_ptr<IPAddress> address (new IPAddress(IPAddress::IPADDRESSTYPE_IPV4, *uriHost));
      client->SynchConnect(address, uriPort);   
   }
   catch (exception e) {
      boost::shared_ptr<string> messageException (new string(e.what()));
      boost::shared_ptr<string> message (new string("Http error creating http connection: " + (*messageException)));

      OnHttpResponse()->Invoke(true,  message);

      try {
         client->Shutdown();
      }
      catch (exception e) {
         boost::shared_ptr<string> messageException (new string(e.what()));
         boost::shared_ptr<string> message (new string("Error during http scocket shutdown: " + (*messageException)));

         OnHttpResponse()->Invoke(true,  message);
      }

      return;
   }


After some thought - we can see why doing a DNS lookup for each unique HTTP request to the server would be a bit excessive. However, it would be a good idea to do the IP address resolution and store it as an "endpoint address" so that the DNS lookup does not need to happen for each poll/message from the server. Forcing the use of an IP address is really bad for portability. What if I change servers, or data centers and get assigned a different permanent IP address? I can migrate my SFS2X licenses to new servers and that all works fine. However, if I have App Store/Google Play app binaries in the wild with the IP address to SFS2X hard coded, that could be a very big potential problem.

Until this is fixed, we'll attempt to fix on our own. It shouldn't be too hard with the only downside being that we're basically modifying SFS2X C++ client code and will need to maintain that on our own until you guys release a fix for this. If it helps, we'd be more than happy to share our fix in this thread/forum and the team can choose to take our fix and merge into the next SFS2X C++ release or not.
dhuang11
Posts: 38
Joined: 02 May 2014, 08:21

Re: Using domain name instead of IP address for BlueBox

Postby dhuang11 » 27 Jun 2014, 08:58

Ok I think we've fixed this. In the code, it looks like the intention was to always use the DNS resolved IP address for all connections but there was a bug where the wrong value was being set as the lastIpAddress and that was the value that would get used by BBClient to connect to BlueBox after the TCP option has failed.

This is what we changed:

SmartFox.cpp in void SmartFox::Connect(string host, long int port) line 432
lastIpAddress = boost::shared_ptr<string>(new string(host));
changed to:
lastIpAddress = boost::shared_ptr<string>(endpointAddress);

BlueBox now uses the resolved IP address instead of the configured hostname.

We've got more BlueBox questions - but will open a new thread for those as they aren't entirely related to this topic.
dhuang11
Posts: 38
Joined: 02 May 2014, 08:21

Re: Using domain name instead of IP address for BlueBox

Postby dhuang11 » 27 Jun 2014, 08:59

Oh yea - please let us know whether this fix will get merged into the next version of the API so we don't need to maintain such a minor change on our own going forward.

Thanks.
MBagnati
Posts: 125
Joined: 12 Feb 2013, 10:57

Re: Using domain name instead of IP address for BlueBox

Postby MBagnati » 02 Jul 2014, 23:23

Hi,
I think that the software change that you suggest is good.
It will be included in the next API version.

Thanks for your help
Massimo

Return to “SFS2X C++ API”

Who is online

Users browsing this forum: No registered users and 1 guest