When a local BitTorrent client connects to your local opentracker server the ip address seen by the tracker will be the private ip address of your router like 10.1.1.1 or 192.168.1.1. When other external clients connect to the tracker that local ip address won’t do them any good. Those external clients need to know your public ip address.

We can modify opentracker to store your public ip address whenever it detects your private ip address. Start by adding two new configuration values to your opentracker.conf file.

tracker.private_ip 192.168.1.1
tracker.public_ip 35.8.10.15

Now edit opentracker.c and add global definitions for the public and private ip address.

/* Globals */
time_t       g_now_seconds;
char *       g_redirecturl;
char *       g_publicip;
char *       g_privateip;
// other code not shown...

Next edit opentracker.c and look for the parse_configfile function. Add the conditions to read in the new private_ip and public_ip values.

/* Scan for commands */
if(!byte_diff(p,15,"tracker.rootdir" ) && isspace(p[15])) {
set_config_option( &g_serverdir, p+16 );
} else if(!byte_diff(p,17,"tracker.public_ip" ) && isspace(p[17])) {
set_config_option( &g_publicip, p+18 );
} else if(!byte_diff(p,18,"tracker.private_ip" ) && isspace(p[18])) {
set_config_option( &g_privateip, p+19 );
}
// other code not shown...

Now edit ot_http.c and add an extern reference to the public and private ip variables.

#define OT_MAXMULTISCRAPE_COUNT 64
extern char *g_redirecturl;
extern char *g_publicip;
extern char *g_privateip;
// other code now shown...

Next edit ot_http.c and look for the http_handle_announce function. This is where we’ll add the code to look for the private ip address and replace it with the public one.

  ws->peer_id = NULL;
  ws->hash = NULL;

  OT_SETIP( &ws->peer, cookie->ip );

  // Check if this is a local peer
  ot_ip6 tmpprivateip;
  scan_ip6( g_privateip, tmpprivateip );

  if( memcmp( tmpprivateip, cookie->ip, sizeof(ot_ip6) ) == 0 )
  {
	  ot_ip6 tmppublicip;
      scan_ip6( g_publicip, tmppublicip );

      char _debug[512];
      int off = snprintf( _debug, sizeof(_debug), "Found private ip, setting public ip:" );
	  off += fmt_ip6c( _debug+off, tmppublicip );
	  off += snprintf( _debug+off, sizeof(_debug)-off, "\n" );
      write( 2, _debug, off );

      // Override the local ip address
	  OT_SETIP( &ws->peer, tmppublicip );
  }
// other code not shown...

Compile opentracker normally and you should be able to see the debug message when a local client connects to your tracker. Warning: This modification works for me (on my machine). It has not been throughly tested.

I’ve removed the Twitter/Song.ly integration from this new release. That feature has always felt half-baked to me anyway. It’s easy to get excited about integrating everything (Twitter, Facebook, etc., etc.) into an iPhone app, but Stream.ly is about streaming radio, so that’s where I want to focus future development.

If you open a compatible streaming radio link in Safari on the iPhone it will open a QuickTime player that will play the stream. Since Safari is allowed to run in the background, you can press the home button and start up other applications while the stream is still playing in Safari. The downside is that you can’t do anything else in Safari while the stream is playing.

Try it. Click on the Indie 103.1 playlist URL or the Houndstooth Radio stream URL from your iPhone.

I’ll add a feature to Stream.ly in the next update to do this automatically from the application. I’ll also update the Stream.ly website so you can browse the station directory from Safari on the phone and listen to a station without needing the application itself. The application adds a lot of nice features though.

UPDATE: It’s still in a “beta” stage, but you can now browse around the Stream.ly Radio web directory and play stations in Safari from this URL. iPhone only for now.

MWHXKN6Y3W9L
XFPT4LPTJWWE
ERL74NXJL9RW
WKMF7TYLLKPR
NY3R6PE7WHTL
64TWKLAN9HFA
R4NNWK3A3PE6
LAL7MJPTAT76
J6EFKX7ANKYK
EN3PWFP3X3F9

You can copy-paste one of these code into iTunes. Click on the Redeem link in the iTunes Store Quick Links box.

Enjoy!

SmackFu has a great page that documents the ShoutCAST metatdata protocol. They don’t mention the difference in the server response, but you’ll find references to it on Google.

When  you send an HTTP GET request to an Icecast server (like Indie 103.1) it replies with HTTP 200 OK. This is what we’d expect, and you can use CFHTTPMessageCopyHeaderFieldValue to read the response header where you get the Icy-MetaInt value. SHOUTcast responds to an HTTP GET request with ICY 200 OK. When this happens CFHTTPMessageCopyHeaderFieldValue returns null.

One solution is to look for the ICY 200 OK response and parse the headers manually. I’ve created another Google Code project called audiostreamer-meta and used Matt Gallagher’s execelent AudioStreamer example as a sample project. The sample application will parse the metadata from both server streams. Check the debug window in Xcode to see the metadata. The code needs some clean up, and it would be nice to display the artist, tract, and other metadata on the view itself. Feel free to join the project and help make the code better.

You’ll have to configure FStream with the following URL:

http://provisioning.streamtheworld.com/pls/KDLDFM.pls

Download stats for the three weeks my app was available (2/2/09 – 2/22/09):

US downloads: 5,140

Non-US downloads: 1,802

Total worldwide downloads: 6,942

Thanks to the people at Indie and everyone who downloaded my app. It’s been fun!

A new version of the Indie 103.1 iPhone app has been published to the iTunes App Store. This update adds artist and title information from the mp3 stream. If you’ve already installed version 1.0 you’ll get an update notice on your phone, or you can update to the new version in iTunes.

NOTE: If you don’t see it yet it could take a bit for your iTunes to pick it up. I just got the update from the App Store on my phone.

Indie 103.1 App Version 1.1

Big thanks to everyone on Twitter who has helped get the word out. We’ve been climbing up the Top Fee apps list in the music category on iTunes. Let’s push it to the top!