利用RHSocketKit构建自定义协议通信

利用RHSocketKit构建自定义协议通信

在网络传输中，tcp/ip协议只是网络的基础，分别属于传输层和网络层。我们各种应用之间的通信需要依赖各种各样的协议，是建立在tcp/ip之上的，比如典型的http协议。

在开发过程中，一般我们制定的协议需要两个部分，header和content。

1-header：协议头部，放置一些meta信息。

2-content：应用之间交互的信息主体。

例如：分隔符delimiter－2个字节｜数据包类型type－2个字节｜长度length（不含包头长度）－4个字节｜数据信息主体content－length个子节

其中delimiter，type，length就是header信息，content就是交互的主体。

我们来利用RHSocketKit构造一个数据包对象。

#import "RHSocketPacketContext.h"@interface RHSocketCustomRequest : RHSocketPacketRequest//这里，我们把content数据放在夫类的object变量中。//length可以通过object数据直接获得，不再申明额外的变量。@property (nonatomic, assign) int16_t fenGeFu;@property (nonatomic, assign) int16_t dataType;@end

数据包已经创建好了，那么我们在RHSocketKit中如何去对这种自定义的协议编码（Encode）呢？

定义编码协议RHSocketEncoderProtocol和解码协议RHSocketDecoderProtocol。

RHSocketCustom0330Encoder：编码器，将发送包的数据从一种格式转换成二进制数组。

RHSocketCustom0330Decoder：解码器，将接收包的二进制数组转换成可读的变量数据。

RHSocketCustom0330Encoder文件

#import <Foundation/Foundation.h>#import "RHSocketCodecProtocol.h"@interface RHSocketCustom0330Encoder : NSObject <RHSocketEncoderProtocol>@end#import "RHSocketCustom0330Encoder.h"#import "RHSocketException.h"#import "RHSocketUtils.h"#import "RHSocketCustomRequest.h"@implementation RHSocketCustom0330Encoder- (void)encode:(id<RHUpstreamPacket>)upstreamPacket output:(id<RHSocketEncoderOutputProtocol>)output{    id object = [upstreamPacket object];    if (![object isKindOfClass:[NSData class]]) {        [RHSocketException raiseWithReason:@"[Encode] object should be NSData ..."];        return;    }        NSData *data = object;    if (data.length == 0) {        return;    }//        RHSocketCustomRequest *req = (RHSocketCustomRequest *)upstreamPacket;    NSUInteger dataLen = data.length;    //<strong><span style="color:#ff0000;">注意这里，按照协议的描述，顺序把数值转成二进制填充到对应的位置，然后output输出</span></strong>    NSMutableData *sendData = [[NSMutableData alloc] init];    //分隔符 2个字节    [sendData appendData:[RHSocketUtils bytesFromUInt16:req.fenGeFu]];    //数据包类型 2个字节    [sendData appendData:[RHSocketUtils bytesFromUInt16:req.dataType]];    //长度（不含包头长度） 4个字节    [sendData appendData:[RHSocketUtils bytesFromUInt32:(uint32_t)dataLen]];    //数据包 dataLen个字节    [sendData appendData:data];        NSTimeInterval timeout = [upstreamPacket timeout];        RHSocketLog(@"timeout: %f, sendData: %@", timeout, sendData);    [output didEncode:sendData timeout:timeout];}@end

RHSocketCustom0330Decoder文件

#import <Foundation/Foundation.h>#import "RHSocketCodecProtocol.h"@interface RHSocketCustom0330Decoder : NSObject <RHSocketDecoderProtocol>@end#import "RHSocketCustom0330Decoder.h"#import "RHSocketException.h"#import "RHSocketUtils.h"#import "RHSocketCustomResponse.h"@interface RHSocketCustom0330Decoder (){    NSUInteger _countOfLengthByte;}@end@implementation RHSocketCustom0330Decoder- (instancetype)init{    if (self = [super init]) {        _countOfLengthByte = 8;    }    return self;}- (NSInteger)decode:(id<RHDownstreamPacket>)downstreamPacket output:(id<RHSocketDecoderOutputProtocol>)output{    id object = [downstreamPacket object];    if (![object isKindOfClass:[NSData class]]) {        [RHSocketException raiseWithReason:@"[Decode] object should be NSData ..."];        return -1;    }        NSData *downstreamData = object;    NSUInteger headIndex = 0;        while (downstreamData && downstreamData.length - headIndex >= _countOfLengthByte) {        NSData *headData = [downstreamData subdataWithRange:NSMakeRange(headIndex, _countOfLengthByte)];        //去第4个字节开始的4个字节长度        NSData *lenData = [headData subdataWithRange:NSMakeRange(4, 4)];        //长度字节数据，可能存在高低位互换，通过数值转换工具处理        NSUInteger frameLen = [RHSocketUtils uint32FromBytes:lenData];                //剩余数据，不是完整的数据包，则break继续读取等待        if (downstreamData.length - headIndex < _countOfLengthByte + frameLen) {            break;        }        //数据包(长度＋内容)        NSData *frameData = [downstreamData subdataWithRange:NSMakeRange(headIndex, _countOfLengthByte + frameLen)];                //去除数据长度后的数据内容        RHSocketCustomResponse *rsp = [[RHSocketCustomResponse alloc] init];        rsp.fenGeFu = [RHSocketUtils uint16FromBytes:[headData subdataWithRange:NSMakeRange(0, 2)]];        rsp.dataType = [RHSocketUtils uint16FromBytes:[headData subdataWithRange:NSMakeRange(2, 2)]];        rsp.object = [frameData subdataWithRange:NSMakeRange(_countOfLengthByte, frameLen)];                [output didDecode:rsp];                //调整已经解码数据        headIndex += frameData.length;    }//while    return headIndex;}@end

codec组件已经准备就绪，接下来我们增加调用控制。RHSocketKit中已经提供了一个单例的service，已经提取和封装了可重用代码。只需要重载编解码器就可以了。

    //这里的服务器对应RHSocketServerDemo，连接之前，需要运行RHSocketServerDemo开启服务端监听。    //RHSocketServerDemo服务端只是返回数据，收到的数据是原封不动的，用来模拟发送给客户端的数据。    NSString *host = @"127.0.0.1";    int port = 20162;        //变长编解码。包体＝包头（包体的长度）＋包体数据    RHSocketCustom0330Encoder *encoder = [[RHSocketCustom0330Encoder alloc] init];    RHSocketCustom0330Decoder *decoder = [[RHSocketCustom0330Decoder alloc] init];        [RHSocketService sharedInstance].encoder = encoder;    [RHSocketService sharedInstance].decoder = decoder;        [[RHSocketService sharedInstance] startServiceWithHost:host port:port];

<span style="font-size:18px;">编写一个服务端对这个通信协议作测试，我这里使用简单的echo服务器测试。代码很简单，我就不贴了。</span>

<span style="font-size:18px;">可以直接查看源码<a target=_blank href="https://github.com/zhu410289616/RHSocketKit/tree/master/RHSocketServerDemo">RHSocketServerDemo</a>。</span>

客户端的过程是，先连接服务器，然后发送数据包。然后服务端返回相同的数据包给客户端，客户端做解码，然后输出展示。

测试代码如下：

#import "ViewController.h"#import "RHSocketService.h"#import "RHSocketCustom0330Encoder.h"#import "RHSocketCustom0330Decoder.h"#import "RHSocketCustomRequest.h"#import "RHSocketCustomResponse.h"@interface ViewController (){    UIButton *_serviceTestButton;}@end@implementation ViewController- (void)loadView{    [super loadView];        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(detectSocketServiceState:) name:kNotificationSocketServiceState object:nil];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(detectSocketPacketResponse:) name:kNotificationSocketPacketResponse object:nil];}- (void)dealloc{    [[NSNotificationCenter defaultCenter] removeObserver:self];}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.        _serviceTestButton = [UIButton buttonWithType:UIButtonTypeCustom];    _serviceTestButton.frame = CGRectMake(20, 120, 250, 40);    _serviceTestButton.layer.borderColor = [UIColor blackColor].CGColor;    _serviceTestButton.layer.borderWidth = 0.5;    _serviceTestButton.layer.masksToBounds = YES;    [_serviceTestButton setTitleColor:[UIColor darkGrayColor] forState:UIControlStateNormal];    [_serviceTestButton setTitle:@"Test Custom Codec" forState:UIControlStateNormal];    [_serviceTestButton addTarget:self action:@selector(doTestServiceButtonAction) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:_serviceTestButton];    }- (void)doTestServiceButtonAction{    //方便多次观察，先停止之前的连接    [[RHSocketService sharedInstance] stopService];        //这里的服务器对应RHSocketServerDemo，连接之前，需要运行RHSocketServerDemo开启服务端监听。    //RHSocketServerDemo服务端只是返回数据，收到的数据是原封不动的，用来模拟发送给客户端的数据。    NSString *host = @"127.0.0.1";    int port = 20162;        //变长编解码。包体＝包头（包体的长度）＋包体数据    RHSocketCustom0330Encoder *encoder = [[RHSocketCustom0330Encoder alloc] init];    RHSocketCustom0330Decoder *decoder = [[RHSocketCustom0330Decoder alloc] init];        [RHSocketService sharedInstance].encoder = encoder;    [RHSocketService sharedInstance].decoder = decoder;        [[RHSocketService sharedInstance] startServiceWithHost:host port:port];}- (void)detectSocketServiceState:(NSNotification *)notif{    //NSDictionary *userInfo = @{@"host":host, @"port":@(port), @"isRunning":@(_isRunning)};    //对应的连接ip和状态数据。_isRunning为YES是连接成功。    //没有心跳超时后会自动断开。    NSLog(@"detectSocketServiceState: %@", notif);        id state = notif.object;    if (state && [state boolValue]) {        //连接成功后，发送数据包        RHSocketCustomRequest *req = [[RHSocketCustomRequest alloc] init];        req.fenGeFu = 0x24;        req.dataType = 1234;        req.object = [@"变长编码器和解码器测试数据包1" dataUsingEncoding:NSUTF8StringEncoding];        [[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];                req = [[RHSocketCustomRequest alloc] init];        req.fenGeFu = 0x24;        req.dataType = 12;        req.object = [@"变长编码器和解码器测试数据包20" dataUsingEncoding:NSUTF8StringEncoding];        [[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];                req = [[RHSocketCustomRequest alloc] init];        req.fenGeFu = 0x24;        req.dataType = 0;        req.object = [@"变长编码器和解码器测试数据包300" dataUsingEncoding:NSUTF8StringEncoding];        [[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];            } else {        //    }//if}- (void)detectSocketPacketResponse:(NSNotification *)notif{    NSLog(@"detectSocketPacketResponse: %@", notif);        //这里结果，记得观察打印的内容    NSDictionary *userInfo = notif.userInfo;    RHSocketCustomResponse *rsp = userInfo[@"RHSocketPacket"];    NSLog(@"detectSocketPacketResponse data: %@", [rsp object]);    NSLog(@"detectSocketPacketResponse string: %@", [[NSString alloc] initWithData:[rsp object] encoding:NSUTF8StringEncoding]);}

源码RHSocketCustomCodecDemo已经上传到github中，可以自行下载。

（demo中是通过pod引入RHSocketKit库的，已经包含了Podfile文件，pod install后就可以正常运行）

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