推薦閱讀：備戰(zhàn)2020——iOS全新面試題總結(jié)

一、分別用C語(yǔ)言、python、GCDAsyncUdpSocket來(lái)實(shí)現(xiàn)UDP通信

1、C語(yǔ)言方式

• 首先初始化socket對(duì)象，Udp要用SOCK_DGRAM
• 然后初始化sockaddr_in網(wǎng)絡(luò)通信對(duì)象，如果作為服務(wù)端要綁定socket對(duì)象與通信鏈接，來(lái)接收消息
• 然后開(kāi)啟一個(gè)循環(huán)，循環(huán)調(diào)用recvfrom來(lái)接收消息
• 收到消息后，保存下發(fā)消息對(duì)象的地址，以便之后回復(fù)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可是是本服務(wù)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(@"來(lái)自%@---%zd:%@",_destHost,_destPort,message);
    }
}

• 由于開(kāi)啟while循環(huán)來(lái)一直接收消息，所以為了避免阻塞主線程，這里要將initCSocket函數(shù)放在子線程中調(diào)用

dispatch_async(dispatch_get_global_queue(0, 0), ^{

        [self initCSocket];
    });

• 調(diào)用sendto方法來(lái)發(fā)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對(duì)象

• 綁定端口，調(diào)用beginReceiving：方法來(lái)接收消息

- (void)initGCDSocket
{
    _receiveSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self
                                                   delegateQueue:dispatch_get_global_queue(0, 0)];
    NSError *error;

    // 綁定一個(gè)端口(可選),如果不綁定端口, 那么就會(huì)隨機(jī)產(chǎn)生一個(gè)隨機(jī)的唯一的端口
    // 端口數(shù)字范圍(1024,2^16-1)
    [_receiveSocket bindToPort:test_port error:&error];

    if (error) {
        NSLog(@"服務(wù)器綁定失敗");
    }
    // 開(kāi)始接收對(duì)方發(fā)來(lái)的消息
    [_receiveSocket beginReceiving:nil];
}

• 在代理方法里獲取到對(duì)方發(fā)過(guò)來(lái)的消息，記錄下主機(jī)和端口，以便之后回復(fù)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(@"來(lái)自%@---%zd:%@",_destHost,_destPort,message);
}

• 調(diào)用sendData:(NSData *)data toHost:(NSString *)host port:(uint16_t)port withTimeout:(NSTimeInterval)timeout tag:(long)tag方法來(lái)發(fā)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方式就比較簡(jiǎn)單了

• 初始化socket，綁定端口

socket = socket(AF_INET, SOCK_DGRAM)

socket.bind(('', port))

• 循環(huán)接收消息

while True:
    message, address = socket.recvfrom(2048)
    print address,message

• 發(fā)送消息

socket.sendto(message, address)

二、利用python實(shí)現(xiàn)Udp通信demo

• 創(chuàng)建兩個(gè)python文件，分別作為客戶端和服務(wù)端，然后同時(shí)運(yùn)行

• 客戶端

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

• 服務(wù)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)

• 客戶端打印

/usr/local/bin/python2.7 /Users/wangyong/Desktop/other/python/UDPClient.py
input message ,print 0 to close :
hello，服務(wù)端
hello，客戶端 ('10.208.61.53', 12000)
input message ,print 0 to close :
結(jié)束通信吧我們
好的 ('10.208.61.53', 12000)
input message ,print 0 to close :
0

Process finished with exit code 0

• 服務(wù)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，服務(wù)端
input message ,print 0 to close :
hello，客戶端
('10.208.61.53', 53500) 結(jié)束通信吧我們
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的簡(jiǎn)易聊天demo

1、UdpManager

Udp通信用C語(yǔ)言版和GCDAsyncUdpSocket都可以，封裝在UdpManager中

• initSocketWithReceiveHandle:(dispatch_block_t)receiveHandle：初始化socket相關(guān)，receiveHandle是接收到消息后的回調(diào)
• sendMessage:(NSString *)message：發(fā)送消息
• messageArray:消息列表，包括接收到的和發(fā)送出去的消息

+ (void)initSocketWithReceiveHandle:(dispatch_block_t)receiveHandle;

+ (void)sendMessage:(NSString *)message;

+ (NSMutableArray *)messageArray;

消息內(nèi)容用MessageModel,其中role代表消息發(fā)送對(duì)象，為0即是接收到的消息，1為自己發(fā)送的消息

@interface MessageModel:NSObject

@property (nonatomic, copy) NSString *message;

@property(nonatomic,assign) NSInteger role;

@end

2、ViewController

控制器里調(diào)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即點(diǎn)擊鍵盤(pán)的發(fā)送按鈕時(shí)發(fā)送編輯好的消息

#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;
}

發(fā)送或者接收到新消息后都會(huì)將消息添加到messageArray里，并刷新頁(yè)面

- (void)sendMessage:(NSString *)message
{
    NSData *sendData = [message dataUsingEncoding:NSUTF8StringEncoding];

    [self.messageArray addObject:[[MessageModel alloc] initWithMessage:message role:1]];

#ifdef UseGCDUdpSocket

    // 該函數(shù)只是啟動(dòng)一次發(fā)送 它本身不進(jìn)行數(shù)據(jù)的發(fā)送, 而是讓后臺(tái)的線程慢慢的發(fā)送 也就是說(shuō)這個(gè)函數(shù)調(diào)用完成后,數(shù)據(jù)并沒(méi)有立刻發(fā)送,異步發(fā)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就不多做介紹了，控制器里只有一個(gè)顯示接收和發(fā)送消息內(nèi)容列表的tableView及一個(gè)編輯消息的輸入框textField。大概就這些內(nèi)容，只是個(gè)簡(jiǎn)易的demo，只實(shí)現(xiàn)了接收發(fā)送文字消息的功能，并沒(méi)有做更多優(yōu)化

3、測(cè)試

分別用模擬器和真機(jī)運(yùn)行，或者可以配合剛才的python程序測(cè)試.
test_host就直接用電腦ip即可

image

• 然后手機(jī)先發(fā)送消息到模擬器上，模擬器就可以根據(jù)記錄下的手機(jī)的主機(jī)和端口回復(fù)消息了。這里手機(jī)連外網(wǎng)也是可以的

• 效果圖如下

  image

Github代碼地址