NSNetServiceBrowser找不到服务

Question

我试图基于CocoaEcho示例编写一个客户端(IPad)/Server(IMac)应用程序。我的第一个简单示例起作用了，但在添加更多功能后，客户端无法找到服务器。

在启动服务器之后，我启动客户机，两者都在本地网络中。客户端开始搜索服务，并收到浏览器的"netServiceBrowserWillSearch:“消息，但之后什么也没有发生。再次触发服务搜索，会导致出现"didNotsearch:“消息，错误为-72003，10 (浏览器仍在忙于搜索)。

1)我检查了WiTap应用程序是否可以访问服务器。客户端和服务器连接正确。

2)检查服务器是否发布了带有"dns-sd -B _cocoaecho“的服务，是否检测到。

3)客户端app中的nsnetservicebrowser对象声明为属性，因此不应存在作用域问题。我还检查了调试器，它仍然在那里...

我的代码：

客户端：

    @interface MySocketClient : UIResponder <NSNetServiceBrowserDelegate, NSStreamDelegate>
    {
    ...
    NSNetService * myServer;
    NSString* nextMsg;
    }
    @property (nonatomic, strong, readwrite) NSMutableArray *       services;           // of NSNetService

    @property (nonatomic, strong, readwrite) NSNetServiceBrowser *  serviceBrowser;
    @property (nonatomic, strong, readwrite) NSInputStream *        inputStream;
    @property (nonatomic, strong, readwrite) NSOutputStream *       outputStream;
    @property (nonatomic, strong, readwrite) NSMutableData *        inputBuffer;
    @property (nonatomic, strong, readwrite) NSMutableData *        outputBuffer;

    ....

    -(void) setup{
    ...
    self.serviceBrowser = [[NSNetServiceBrowser alloc] init];
    self.services = [[NSMutableArray alloc] init];
    [self.serviceBrowser setDelegate:self];
    [self.serviceBrowser searchForServicesOfType:@"_cocoaecho._tcp." inDomain:@"local."];
    }

    - (void)netServiceBrowser:(NSNetServiceBrowser *)netServiceBrowser didNotSearch:(NSDictionary *)errorInfo
   {
    NSLog(@"%@", errorInfo);
    }

// Sent when browsing begins
- (void)netServiceBrowserWillSearch:(NSNetServiceBrowser *)browser
{
    NSLog(@"will search \n");
}

// Sent when browsing stops
- (void)netServiceBrowserDidStopSearch:(NSNetServiceBrowser *)browser
{
    NSLog(@"stopped search \n");
}

//We broadcast the willChangeValueForKey: and didChangeValueForKey: for the NSTableView binding to work.
- (void)netServiceBrowser:(NSNetServiceBrowser *)aNetServiceBrowser didFindService:(NSNetService *)aNetService moreComing:(BOOL)moreComing {
#pragma unused(aNetServiceBrowser)
#pragma unused(moreComing)
     NSLog(@"found a service \n");
    if (![self.services containsObject:aNetService]) {
        [self willChangeValueForKey:@"services"];
        [self.services addObject:aNetService];
        [self didChangeValueForKey:@"services"];
        myServer = aNetService;
    }
}

- (void)netServiceBrowser:(NSNetServiceBrowser *)aNetServiceBrowser didRemoveService:(NSNetService *)aNetService moreComing:(BOOL)moreComing {
#pragma unused(aNetServiceBrowser)
#pragma unused(moreComing)
    if ([self.services containsObject:aNetService]) {
        [self willChangeValueForKey:@"services"];
        [self.services removeObject:aNetService];
        [self didChangeValueForKey:@"services"];
    }
}

和服务器：

    - (BOOL)start {
    assert(_ipv4socket == NULL && _ipv6socket == NULL);       // don't call -start twice!

    CFSocketContext socketCtxt = {0, (__bridge void *) self, NULL, NULL, NULL};
    _ipv4socket = CFSocketCreate(kCFAllocatorDefault, AF_INET,  SOCK_STREAM, 0, kCFSocketAcceptCallBack, &EchoServerAcceptCallBack, &socketCtxt);
    _ipv6socket = CFSocketCreate(kCFAllocatorDefault, AF_INET6, SOCK_STREAM, 0, kCFSocketAcceptCallBack, &EchoServerAcceptCallBack, &socketCtxt);

    if (NULL == _ipv4socket || NULL == _ipv6socket) {
        [self stop];
        return NO;
    }

    static const int yes = 1;
    (void) setsockopt(CFSocketGetNative(_ipv4socket), SOL_SOCKET, SO_REUSEADDR, (const void *) &yes, sizeof(yes));
    (void) setsockopt(CFSocketGetNative(_ipv6socket), SOL_SOCKET, SO_REUSEADDR, (const void *) &yes, sizeof(yes));

    // Set up the IPv4 listening socket; port is 0, which will cause the kernel to choose a port for us.
    struct sockaddr_in addr4;
    memset(&addr4, 0, sizeof(addr4));
    addr4.sin_len = sizeof(addr4);
    addr4.sin_family = AF_INET;
    addr4.sin_port = htons(0);
    addr4.sin_addr.s_addr = htonl(INADDR_ANY);
    if (kCFSocketSuccess != CFSocketSetAddress(_ipv4socket, (__bridge CFDataRef) [NSData dataWithBytes:&addr4 length:sizeof(addr4)])) {
        [self stop];
        return NO;
    }

    // Now that the IPv4 binding was successful, we get the port number
    // -- we will need it for the IPv6 listening socket and for the NSNetService.
    NSData *addr = (__bridge_transfer NSData *)CFSocketCopyAddress(_ipv4socket);
    assert([addr length] == sizeof(struct sockaddr_in));
    self.port = ntohs(((const struct sockaddr_in *)[addr bytes])->sin_port);

    // Set up the IPv6 listening socket.
    struct sockaddr_in6 addr6;
    memset(&addr6, 0, sizeof(addr6));
    addr6.sin6_len = sizeof(addr6);
    addr6.sin6_family = AF_INET6;
    addr6.sin6_port = htons(self.port);
    memcpy(&(addr6.sin6_addr), &in6addr_any, sizeof(addr6.sin6_addr));
    if (kCFSocketSuccess != CFSocketSetAddress(_ipv6socket, (__bridge CFDataRef) [NSData dataWithBytes:&addr6 length:sizeof(addr6)])) {
        [self stop];
        return NO;
    }

    // Set up the run loop sources for the sockets.
    CFRunLoopSourceRef source4 = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _ipv4socket, 0);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), source4, kCFRunLoopCommonModes);
    CFRelease(source4);

    CFRunLoopSourceRef source6 = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _ipv6socket, 0);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), source6, kCFRunLoopCommonModes);
    CFRelease(source6);

    assert(self.port > 0 && self.port < 65536);
    self.netService = [[NSNetService alloc] initWithDomain:@"local." type:@"_cocoaecho._tcp." name:@"" port:(int) self.port];
    [self.netService publishWithOptions:0];

    return YES;
}

Answer 1

我只是一直收到-72003错误，除非我断开连接并重新连接(即使是第一次)。这就导致了这个解决方案：

private let serviceBrowser = NSNetServiceBrowser()

serviceBrowser.stop()
serviceBrowser.searchForServicesOfType(TYPE, inDomain: DOMAIN)

我不知道为什么这样做有效，但我不再得到错误。

Answer 2

我也遇到过类似的问题。我的代码成功注册了NSNetService并启动了NSNetServiceBrowser，但无法-resolveWithTimeout其他设备。很奇怪，但有时确实有效，有时不起作用，有时不对称工作。

在紧张的调试之后，我可以给你一些检查的提示：

1. 在桌面上安装Bonjour浏览器。拔下网线并检查您是否连接到与移动设备相同的WiFi热点。在这里你应该看到与移动设备相同的服务状态。
2. 尝试使用不同的WiFi热点。奇怪的是，我的主WiFi表现很差。在我切换到另一个后，它使用完全相同的代码就像一个咒语一样工作。尝试将WiFi从互联网上拔出以进行测试。
3. 您可以添加一些保留(或分配给静态变量)到接口返回的对象(如NSNetService)。如果ARC决定不再需要object，它可以静默解除分配。这对我的一些测试很有帮助。