CocoaDev

I’ve just started using NetSocket in the place of SocketPort and have run into a weird problem. I would like to use rendezvous to discover client apps and establish NetSocket connections to them.

NetSocket needs an IP number (or host) to create the socket. Rendezvous (at least in all the examples and tutorials I could find) resolves services and gives you the socket Struct as a bunch of bytes, which works fine with SocketPort but not with NetSocket (which wants a plain old IP number). How to get human readable (ie not a socket struct) IP number from rendezvous’ “did resolve address’” delegate?

Right now I am cheating and passing [[NSHost currentHost] name] through the the rendezvous service name but this is a mega hack and not the point of rendezvous.

Thanks, as always.

EcumeDesJours

The Picture Sharing Browser example [file:///Developer/Examples/Foundation/PictureSharingBrowser/] retrieves the IP address from a socket struct, but it doesn’t appear to handle IPv6 and feels a little hackish to me. I am also curious for a better solution to this problem considering almost all high level networking frameworks do not accept a socket struct. Anyone have a suggestion? – RyanBates

inet_ntop() is your friend.  Here's my code:

#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h>

NSString* addressStringWithSocketData(NSData* inSocketData) { if (inSocketData == nil) { return nil; } struct sockaddr* sock = (struct sockaddr)[inSocketData bytes]; if (sock->sa_family == AF_INET) { struct sockaddr_in sock_in = (struct sockaddr_in)sock; char buf[INET_ADDRSTRLEN]; const char address = inet_ntop(AF_INET, &(sock_in->sin_addr), buf, INET_ADDRSTRLEN); if (address) { return [NSString stringWithCString:buf]; } } else if (sock->sa_family == AF_INET6) { struct sockaddr_in6* sock_in6 = (struct sockaddr_in6)sock; char buf[INET6_ADDRSTRLEN]; const char address = inet_ntop(AF_INET6, &(sock_in6->sin6_addr), buf, INET6_ADDRSTRLEN); if (address) { return [NSString stringWithCString:buf]; } } return nil; }

The irony of this is that those high-level frameworks generally turn around and create a sockaddr structure behind the scenes so a better solution might be to modify them to take an NSData-wrapped sockaddr. That is, however, left as an exercise for the reader. – Bo

Independently I did this excercise: [http://www.dasgenie.com/scrap/archives/000103.html NSStringNetworkingAdditions]– DominikWagner

Bo, you ROCK!!!! I don’t know what many of us would do without cocoadev!!!