CODEWITHSUNDEEP
iosiphonesocketstcpposix
la-ga
la-ga

Reputation: 160

How to create a TCP Server on the iPhone?

I want to create a TCP server on the iPhone. I tried to write this server using Apple's developer help, but I had no success. I tried to listen with CoreFoundation and with POSIX Socket API but none of these worked.

Using CoreFoundation I implemented the following:

CFSocketRef myipv4cfsock = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP,
                                          kCFSocketAcceptCallBack, handleConnect, NULL);

struct sockaddr_in mySocket;

memset(&mySocket, 0, sizeof(sin));
mySocket.sin_len = sizeof(sin);
mySocket.sin_family = PF_INET;
mySocket.sin_port = 8000;
mySocket.sin_addr.s_addr= INADDR_ANY;

CFSocketSetAddress(myipv4cfsock, CFDataCreate(kCFAllocatorDefault, (UInt8 *)&mySocket, sizeof(mySocket)));

CFRunLoopSourceRef socketsource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, myipv4cfsock, 0);

CFRunLoopAddSource(CFRunLoopGetCurrent(), socketsource, kCFRunLoopDefaultMode);

CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStringRef remoteHost = CFSTR("localhost");
CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)remoteHost, 8000, &readStream, &writeStream);

NSInputStream *inputStream = (__bridge_transfer NSInputStream *)readStream;
NSOutputStream *outputStream = (__bridge_transfer NSOutputStream *)writeStream;

[inputStream setDelegate: self];
[outputStream setDelegate: self];
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[inputStream open];
[outputStream open];

Using the POSIX Socket API I implemented this:

int listenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

struct sockaddr_in socketAddr;
memset(&socketAddr, 0, sizeof(socketAddr));
socketAddr.sin_len = sizeof(sin);
socketAddr.sin_family = AF_INET;
socketAddr.sin_port = 8000;
socketAddr.sin_addr.s_addr= INADDR_ANY;

if (bind(listenSocket, (struct sockaddr *)&socketAddr, sizeof(socketAddr)) < 0)
{
    NSLog(@"Error: Could not bind socket.");
}

listen(listenSocket, 10);

But then I didn't know how to handle the events with Grand Central Dispatch.

When I try to connect with some client I always get the exception "Connection refused" on client side.

Does anybody have some example code?

Upvotes: 1

Views: 2547

Answers (1)

la-ga
la-ga

Reputation: 160

I found a solution using the POSIX Socket API.

int listenfd = 0;
struct sockaddr_in serv_addr;

listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(8008);

bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

_listenForConnections = true;
listen(listenfd, 10);

dispatch_async(dispatch_get_global_queue(0, 0), ^{
    NSLog(@"Waiting for connections...");
    while (_listenForConnections)
    {
        __block int connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
        NSLog(@"Connection accepted");

        char buffer[1024];
        bzero(buffer, 1024);
        NSString *message = @"";
        bool continueReading = true;

        do
        {
            recv(connfd , buffer , 1024 , 0);
            int size = strlen(buffer);
            if ((buffer[size-1] == '}' && buffer[size-2] == '{'))
            {
                continueReading = false;
                buffer[size-2] = '\0';
            }
            message = [NSString stringWithFormat: @"%@%s", message, buffer];
        }while (continueReading);
        NSLog(@"Got message from client");

        char* answer = "Hello World";
        write(connfd, answer, strlen(answer));
    }

    NSLog(@"Stop listening.");
    close(listenfd);
});

Upvotes: 2

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