CocoaAsyncSocket网络通信使用之tcp连接

简述：

在互联网世界中，网络访问是必不可少的一部分，而对于程序员来说，网络编程却是一个比较复杂的存在，特别是socket处理方面。

在android平台中，java类库丰富，封装良好，比如：mina，netty等等。

而在ios平台中，也有出名的socket库，CocoaAsyncSocket。

最近碰到一些朋友在socket的应用上一直不是特别熟悉，自己在接触过socket底层库，使用过mina，netty和CocoaAsyncSocket后，

也想整理一份自己的工具库，于是有如下内容。

CocoaAsyncSocket的功能强大，有tcp和udp两部分，这里只学习整理tcp部分。

建立ios工程：

首先建立一个ios工程，RHSocketDemo. （本例使用pod管理类库，如果不熟悉，可以先看前面的文章：CocoaPods安装和使用教程）

然后在工程目录下建立Podfile文件，内容如下：

platform:ios,'7.0'

pod 'CocoaAsyncSocket', '~> 7.4.1'

然后使用pod instatll —no-repo-update命令，生成工程管理文件。

关闭原先的工程，使用新生成的RHSocketDemo.xcworkspace文件开启工程。

以上是通过pod引入CocoaAsyncSocket库，省去了加入framework的步骤，，比较方便。

也可以下载CocoaAsyncSocket源码，然后将源码加入到工程中，但是需要额外手动加入framework。

构造自己的socket连接类：

1-为了简化类库中的内容，隐藏一些不关心的接口方法。

2-对类库做一层封装隔离，以个人习惯的方式呈现使用（可以方便库的更新替换，比如：asi到afn的http 库迁移）

基于以上两个原因，我们使用CocoaAsyncSocket封装自己的sokcet connection类。代码如下：

RHSocketConfig.h文件：

 #ifndef RHSocketDemo_RHSocketConfig_h
 #define RHSocketDemo_RHSocketConfig_h

 #ifdef DEBUG
 #define RHSocketDebug
 #endif

 #ifdef RHSocketDebug
 #define RHSocketLog(format, ...) NSLog(format, ## __VA_ARGS__)
 #else
 #define RHSocketLog(format, ...)
 #endif

 #endif

RHSocketConnection.h文件：

 #import <Foundation/Foundation.h>
 #import "RHSocketConfig.h"

 @protocol RHSocketConnectionDelegate <NSObject>

 - (void)didDisconnectWithError:(NSError *)error;
 - (void)didConnectToHost:(NSString *)host port:(UInt16)port;
 - (void)didReceiveData:(NSData *)data tag:(long)tag;

 @end

 @interface RHSocketConnection : NSObject

 @property (nonatomic, weak) id<RHSocketConnectionDelegate> delegate;

 - (void)connectWithHost:(NSString *)hostName port:(int)port;
 - (void)disconnect;

 - (BOOL)isConnected;
 - (void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag;
 - (void)writeData:(NSData *)data timeout:(NSTimeInterval)timeout tag:(long)tag;

 @end

RHSocketConnection.m文件：

 #import "RHSocketConnection.h"
 #import "GCDAsyncSocket.h"

 @interface RHSocketConnection () <GCDAsyncSocketDelegate>
 {
     GCDAsyncSocket *_asyncSocket;
 }

 @end

 @implementation RHSocketConnection

 - (instancetype)init
 {
     if (self = [super init]) {
         _asyncSocket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];
     }
     return self;
 }

 - (void)dealloc
 {
     _asyncSocket.delegate = nil;
     _asyncSocket = nil;
 }

 - (void)connectWithHost:(NSString *)hostName port:(int)port
 {
     NSError *error = nil;
     [_asyncSocket connectToHost:hostName onPort:port error:&error];
     if (error) {
         RHSocketLog(@"[RHSocketConnection] connectWithHost error: %@", error.description);
         if (_delegate && [_delegate respondsToSelector:@selector(didDisconnectWithError:)]) {
             [_delegate didDisconnectWithError:error];
         }
     }
 }

 - (void)disconnect
 {
     [_asyncSocket disconnect];
 }

 - (BOOL)isConnected
 {
     return [_asyncSocket isConnected];
 }

 - (void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag
 {
     [_asyncSocket readDataWithTimeout:timeout tag:tag];
 }

 - (void)writeData:(NSData *)data timeout:(NSTimeInterval)timeout tag:(long)tag
 {
     [_asyncSocket writeData:data withTimeout:timeout tag:tag];
 }

 #pragma mark -
 #pragma mark GCDAsyncSocketDelegate method

 - (void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err
 {
     RHSocketLog(@"[RHSocketConnection] didDisconnect...%@", err.description);
     if (_delegate && [_delegate respondsToSelector:@selector(didDisconnectWithError:)]) {
         [_delegate didDisconnectWithError:err];
     }
 }

 - (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(uint16_t)port
 {
     RHSocketLog(@"[RHSocketConnection] didConnectToHost: %@, port: %d", host, port);
     if (_delegate && [_delegate respondsToSelector:@selector(didConnectToHost:port:)]) {
         [_delegate didConnectToHost:host port:port];
     }
 }

 - (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag
 {
     RHSocketLog(@"[RHSocketConnection] didReadData length: %lu, tag: %ld", (unsigned long)data.length, tag);
     if (_delegate && [_delegate respondsToSelector:@selector(didReceiveData:tag:)]) {
         [_delegate didReceiveData:data tag:tag];
     }
     [sock readDataWithTimeout:-1 tag:tag];
 }

 - (void)socket:(GCDAsyncSocket *)sock didWriteDataWithTag:(long)tag
 {
     RHSocketLog(@"[RHSocketConnection] didWriteDataWithTag: %ld", tag);
     [sock readDataWithTimeout:-1 tag:tag];
 }

 @end

测试调用的ViewController.m文件：

 #import "ViewController.h"
 #import "RHSocketConnection.h"

 @interface ViewController () <RHSocketConnectionDelegate>
 {
     NSString *_serverHost;
     int _serverPort;
     RHSocketConnection *_connection;
 }

 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];

     // Do any additional setup after loading the view, typically from a nib.

     _serverHost = @"www.baidu.com";
     _serverPort = 80;
     [self openConnection];
 }

 #pragma mark -
 #pragma mark RHSocketConnection method

 - (void)openConnection
 {
     [self closeConnection];
     _connection = [[RHSocketConnection alloc] init];
     _connection.delegate = self;
     [_connection connectWithHost:_serverHost port:_serverPort];
 }

 - (void)closeConnection
 {
     if (_connection) {
         _connection.delegate = nil;
         [_connection disconnect];
         _connection = nil;
     }
 }

 #pragma mark -
 #pragma mark RHSocketConnectionDelegate method

 - (void)didDisconnectWithError:(NSError *)error
 {
     RHSocketLog(@"didDisconnectWithError...");
 }

 - (void)didConnectToHost:(NSString *)host port:(UInt16)port
 {
     RHSocketLog(@"didConnectToHost...");
 }

 - (void)didReceiveData:(NSData *)data tag:(long)tag
 {
     RHSocketLog(@"didReceiveData...");
 }

 @end

上面的代码中，RHSocketConnection负责网络的连接，ViewController负责测试代码。

连接成功后，会输出：[RHSocketConnection] didConnectToHost: 115.239.210.27, port: 80

以下是测试调用的主要方法：

 NSString *serverHost = @"www.baidu.com";
 int serverPort = 80;
 RHSocketConnection *connection = [[RHSocketConnection alloc] init];
 [connection connectWithHost:serverHost port:serverPort];