推荐阅读：备战2020——iOS全新面试题总结
一、分别用C语言、python、GCDAsyncUdpSocket来实现UDP通信
1、C语言方式
- 首先初始化
socket对象，Udp要用SOCK_DGRAM - 然后初始化
sockaddr_in网络通信对象，如果作为服务端要绑定socket对象与通信链接，来接收消息 - 然后开启一个循环，循环调用
recvfrom来接收消息 - 收到消息后，保存下发消息对象的地址，以便之后回复消息
- (void)initCSocket
{
char receiveBuffer[1024];
__uint32_t nSize = sizeof(struct sockaddr);
if ((_listenfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
{
perror("socket() error. Failed to initiate a socket");
}
bzero(&_addr, sizeof(_addr));
_addr.sin_family = AF_INET;
_addr.sin_port = htons(_destPort);
if(bind(_listenfd, (struct sockaddr *)&_addr, sizeof(_addr)) == -1)
{
perror("Bind() error.");
}
_addr.sin_addr.s_addr = inet_addr([_destHost UTF8String]);//ip可是是本服务器的ip，也可以用宏INADDR_ANY代替，代表0.0.0.0，表明所有地址
while(true){
long strLen = recvfrom(_listenfd, receiveBuffer, sizeof(receiveBuffer), 0, (struct sockaddr *)&_addr, &nSize);
NSString * message = [[NSString alloc] initWithBytes:receiveBuffer length:strLen encoding:NSUTF8StringEncoding];
_destPort = ntohs(_addr.sin_port);
_destHost = [[NSString alloc] initWithUTF8String:inet_ntoa(_addr.sin_addr)];
NSLog(@"来自%@---%zd:%@",_destHost,_destPort,message);
}
}
-
由于开启while循环来一直接收消息，所以为了避免阻塞主线程，这里要将
initCSocket函数放在子线程中调用
dispatch_async(dispatch_get_global_queue(0, 0), ^{
[self initCSocket];
});
- 调用
sendto方法来发送消息
- (void)sendMessage:(NSString *)message
{
NSData *sendData = [message dataUsingEncoding:NSUTF8StringEncoding];
sendto(_listenfd, [sendData bytes], [sendData length], 0, (struct sockaddr *)&_addr, sizeof(struct sockaddr));
}
2、GCDAsyncUdpSocket方式
-
GCDAsyncUdpSocket地址
首先初始化
Socket对象绑定端口，调用
beginReceiving：方法来接收消息
- (void)initGCDSocket
{
_receiveSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self
delegateQueue:dispatch_get_global_queue(0, 0)];
NSError *error;
// 绑定一个端口(可选),如果不绑定端口, 那么就会随机产生一个随机的唯一的端口
// 端口数字范围(1024,2^16-1)
[_receiveSocket bindToPort:test_port error:&error];
if (error) {
NSLog(@"服务器绑定失败");
}
// 开始接收对方发来的消息
[_receiveSocket beginReceiving:nil];
}
- 在代理方法里获取到对方发过来的消息，记录下主机和端口，以便之后回复消息
#pragma mark - GCDAsyncUdpSocketDelegate
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data fromAddress:(NSData *)address withFilterContext:(id)filterContext {
NSString *message = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
_destPort = [GCDAsyncUdpSocket portFromAddress:address];
_destHost = [GCDAsyncUdpSocket hostFromAddress:address];
NSLog(@"来自%@---%zd:%@",_destHost,_destPort,message);
}
- 调用
sendData:(NSData *)data toHost:(NSString *)host port:(uint16_t)port withTimeout:(NSTimeInterval)timeout tag:(long)tag方法来发送消息
- (void)sendMessage:(NSString *)message
{
NSData *sendData = [message dataUsingEncoding:NSUTF8StringEncoding];
[_receiveSocket sendData:sendData toHost:_destHost port:_destPort withTimeout:60 tag:500];
}
3、python方式
python方式就比较简单了
- 初始化socket，绑定端口
socket = socket(AF_INET, SOCK_DGRAM)
socket.bind(('', port))
- 循环接收消息
while True:
message, address = socket.recvfrom(2048)
print address,message
- 发送消息
socket.sendto(message, address)
二、利用python实现Udp通信demo
创建两个python文件，分别作为客户端和服务端，然后同时运行
客户端
from socket import *
host = '127.0.0.1'
port = 12000
socket = socket(AF_INET, SOCK_DGRAM)
while True:
message = raw_input('input message ,print 0 to close :\n')
socket.sendto(message, (host, port))
if message == '0':
socket.close()
break
receiveMessage, serverAddress = socket.recvfrom(2048)
print receiveMessage,serverAddress
- 服务端
from socket import *
port = 12000
socket = socket(AF_INET, SOCK_DGRAM)
socket.bind(('', port))
print 'server is ready to receive'
count = 0
while True:
message, address = socket.recvfrom(2048)
print address,message
count = count + 1
if message == '0':
socket.close()
break
else:
message = raw_input('input message ,print 0 to close :\n')
socket.sendto(message, address)
- 客户端打印
/usr/local/bin/python2.7 /Users/wangyong/Desktop/other/python/UDPClient.py
input message ,print 0 to close :
hello，服务端
hello，客户端 ('10.208.61.53', 12000)
input message ,print 0 to close :
结束通信吧我们
好的 ('10.208.61.53', 12000)
input message ,print 0 to close :
0
Process finished with exit code 0
- 服务端打印
/usr/local/bin/python2.7 /Users/wangyong/Desktop/other/python/UDPServer.py
server is ready to receive
('10.208.61.53', 53500) hello，服务端
input message ,print 0 to close :
hello，客户端
('10.208.61.53', 53500) 结束通信吧我们
input message ,print 0 to close :
好的
('10.208.61.53', 53500) 0
Process finished with exit code 0
三、iOS端基于UDP的简易聊天demo
1、UdpManager
Udp通信用C语言版和GCDAsyncUdpSocket都可以，封装在UdpManager中
-
initSocketWithReceiveHandle:(dispatch_block_t)receiveHandle：初始化socket相关，receiveHandle是接收到消息后的回调 -
sendMessage:(NSString *)message：发送消息 -
messageArray:消息列表，包括接收到的和发送出去的消息
+ (void)initSocketWithReceiveHandle:(dispatch_block_t)receiveHandle;
+ (void)sendMessage:(NSString *)message;
+ (NSMutableArray *)messageArray;
消息内容用MessageModel,其中role代表消息发送对象，为0即是接收到的消息，1为自己发送的消息
@interface MessageModel:NSObject
@property (nonatomic, copy) NSString *message;
@property(nonatomic,assign) NSInteger role;
@end
2、ViewController
控制器里调用UdpManager初始化socket
[UdpManager initSocketWithReceiveHandle:^{
dispatch_async(dispatch_get_main_queue(), ^{
self.title = [NSString stringWithFormat:@"%@---%@",[[UdpManager shareManager] valueForKey:@"_destHost"],[[UdpManager shareManager] valueForKey:@"_destPort"]];
[self reloadData];
});
}];
在代理方法textFieldShouldReturn即点击键盘的发送按钮时发送编辑好的消息
#pragma mark - UITextFieldDelegate
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
if (self.textField.text.length == 0) return YES;
[UdpManager sendMessage:self.textField.text];
[self reloadData];
self.textField.text = nil;
return YES;
}
发送或者接收到新消息后都会将消息添加到messageArray里，并刷新页面
- (void)sendMessage:(NSString *)message
{
NSData *sendData = [message dataUsingEncoding:NSUTF8StringEncoding];
[self.messageArray addObject:[[MessageModel alloc] initWithMessage:message role:1]];
#ifdef UseGCDUdpSocket
// 该函数只是启动一次发送 它本身不进行数据的发送, 而是让后台的线程慢慢的发送 也就是说这个函数调用完成后,数据并没有立刻发送,异步发送
[_receiveSocket sendData:sendData toHost:_destHost port:_destPort withTimeout:60 tag:500];
#else
sendto(_listenfd, [sendData bytes], [sendData length], 0, (struct sockaddr *)&_addr, sizeof(struct sockaddr));
#endif
}
UI就不多做介绍了，控制器里只有一个显示接收和发送消息内容列表的tableView及一个编辑消息的输入框textField。大概就这些内容，只是个简易的demo，只实现了接收发送文字消息的功能，并没有做更多优化
3、测试
分别用模拟器和真机运行，或者可以配合刚才的python程序测试.
test_host就直接用电脑ip即可
image
然后手机先发送消息到模拟器上，模拟器就可以根据记录下的手机的主机和端口回复消息了。这里手机连外网也是可以的
-
效果图如下
image