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iTunes includes lots of extra info in its rendezvous service broadcast, such as:



iTSh Version

Machine ID

Machine Name



I don’t see any way to publish extra flags like this in the official API. Anyone know how this is done and how it is parsed by the NSNetserviceBrowser?


That’s the -protocolSpecificInformation and -setProtocolSpecificInformation: methods. The format used for the strings is “x=y\001u=v\001w=z” (that’s ASCII char 0x01 separating each line), so, for example, the code to encode and decode a dictionary of strings (I’m gonna skip the class/error checking) would be:

NSString* encodeOpenTalkTXTRecord(NSDictionary* recs) { NSMutableArray* encodedRecs = [NSMutableArray arrayWithCapacity:[recs count]]; NSEnumerator* dictKeyEnum = [recs keyEnumerator]; NSString* currKey;

while (currKey = [dictKeyEnum nextObject]) {
	NSString* currValue = [recs objectForKey:currKey];
	[encodedRecs addObject:[NSString stringWithFormat:@"%@=%@", currKey, currValue]];
return [encodedRecs componentsJoinedByString:@"\001"]; } NSDictionary* decodeOpenTalkTXTRecord(NSString* rec) {
NSArray* encodedRecs = [rec componentsSeparatedByString:@"\001"];
NSMutableDictionary* decodedRecs = [NSMutableDictionary dictionaryWithCapacity:[encodedRecs count]];
NSEnumerator* recEnum = [encodedRecs objectEnumerator];
NSString* currRec;

while (currRec = [recEnum nextObject]) {
	NSArray* currRecParts = [currRec componentsSeparatedByString:@"="];
	// keep in mind that the records are not required to follow this format
	// so you may wish to check whether you've actually got a two string array
	[decodedRecs setObject:[currRecParts objectAtIndex:1] forKey:[currRecParts objectAtIndex:0]];
return decodedRecs; }

I just typed this up in the browser, so it may not compile, much less work. If there’s a problem, post here and I’ll figure out what’s the matter. – Bo