利用RHSocketKit構建自定義協議通信
在網絡傳輸中，tcp/ip協議只是網絡的基礎，分別屬於傳輸層和網絡層。我們各種應用之間的通信需要依賴各種各樣的協議，是建立在tcp/ip之上的，比如典型的http協議。
在開發過程中，一般我們制定的協議需要兩個部分，header和content。
1-header：協議頭部，放置一些meta信息。
2-content：應用之間交互的信息主體。
例如：分隔符delimiter－2個字節｜數據包類型type－2個字節｜長度length（不含包頭長度）－4個字節｜數據信息主體content－length個子節
其中delimiter，type，length就是header信息，content就是交互的主體。
我們來利用RHSocketKit構造一個數據包對象。
#import "RHSocketPacketContext.h"
@interface RHSocketCustomRequest : RHSocketPacketRequest
//這裏，我們把content數據放在夫類的object變量中。
//length可以通過object數據直接獲得，不再申明額外的變量。
@property (nonatomic, assign) int16_t fenGeFu;
@property (nonatomic, assign) int16_t dataType;
@end數據包已經創建好了，那麼我們在RHSocketKit中如何去對這種自定義的協議編碼（Encode）呢？
定義編碼協議RHSocketEncoderProtocol和解碼協議RHSocketDecoderProtocol。
RHSocketCustom0330Encoder：編碼器，將發送包的數據從一種格式轉換成二進制數組。
RHSocketCustom0330Decoder：解碼器，將接收包的二進制數組轉換成可讀的變量數據。
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;">注意這裏，按照協議的描述，順序把數值轉成二進制填充到對應的位置，然後output輸出</span></strong>
NSMutableData *sendData = [[NSMutableData alloc] init];
//分隔符 2個字節
[sendData appendData:[RHSocketUtils bytesFromUInt16:req.fenGeFu]];
//數據包類型 2個字節
[sendData appendData:[RHSocketUtils bytesFromUInt16:req.dataType]];
//長度（不含包頭長度） 4個字節
[sendData appendData:[RHSocketUtils bytesFromUInt32:(uint32_t)dataLen]];
//數據包 dataLen個字節
[sendData appendData:data];
NSTimeInterval timeout = [upstreamPacket timeout];
RHSocketLog(@"timeout: %f, sendData: %@", timeout, sendData);
[output didEncode:sendData timeout:timeout];
}
@endRHSocketCustom0330Decoder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個字節開始的4個字節長度
NSData *lenData = [headData subdataWithRange:NSMakeRange(4, 4)];
//長度字節數據，可能存在高低位互換，通過數值轉換工具處理
NSUInteger frameLen = [RHSocketUtils uint32FromBytes:lenData];
//剩餘數據，不是完整的數據包，則break繼續讀取等待
if (downstreamData.length - headIndex < _countOfLengthByte + frameLen) {
break;
}
//數據包(長度＋內容)
NSData *frameData = [downstreamData subdataWithRange:NSMakeRange(headIndex, _countOfLengthByte + frameLen)];
//去除數據長度後的數據內容
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];
//調整已經解碼數據
headIndex += frameData.length;
}//while
return headIndex;
}
@endcodec組件已經準備就緒，接下來我們增加調用控制。RHSocketKit中已經提供了一個單例的service，已經提取和封裝了可重用代碼。只需要重載編解碼器就可以了。
//這裏的服務器對應RHSocketServerDemo，連接之前，需要運行RHSocketServerDemo開啓服務端監聽。
//RHSocketServerDemo服務端只是返回數據，收到的數據是原封不動的，用來模擬發送給客戶端的數據。
NSString *host = @"127.0.0.1";
int port = 20162;
//變長編解碼。包體＝包頭（包體的長度）＋包體數據
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;">編寫一個服務端對這個通信協議作測試，我這裏使用簡單的echo服務器測試。代碼很簡單，我就不貼了。</span><span style="font-size:18px;">可以直接查看源碼<a target=_blank href="https://github.com/zhu410289616/RHSocketKit/tree/master/RHSocketServerDemo">RHSocketServerDemo</a>。</span>客戶端的過程是，先連接服務器，然後發送數據包。然後服務端返回相同的數據包給客戶端，客戶端做解碼，然後輸出展示。
測試代碼如下：
#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
{
//方便多次觀察，先停止之前的連接
[[RHSocketService sharedInstance] stopService];
//這裏的服務器對應RHSocketServerDemo，連接之前，需要運行RHSocketServerDemo開啓服務端監聽。
//RHSocketServerDemo服務端只是返回數據，收到的數據是原封不動的，用來模擬發送給客戶端的數據。
NSString *host = @"127.0.0.1";
int port = 20162;
//變長編解碼。包體＝包頭（包體的長度）＋包體數據
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)};
//對應的連接ip和狀態數據。_isRunning爲YES是連接成功。
//沒有心跳超時後會自動斷開。
NSLog(@"detectSocketServiceState: %@", notif);
id state = notif.object;
if (state && [state boolValue]) {
//連接成功後，發送數據包
RHSocketCustomRequest *req = [[RHSocketCustomRequest alloc] init];
req.fenGeFu = 0x24;
req.dataType = 1234;
req.object = [@"變長編碼器和解碼器測試數據包1" dataUsingEncoding:NSUTF8StringEncoding];
[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];
req = [[RHSocketCustomRequest alloc] init];
req.fenGeFu = 0x24;
req.dataType = 12;
req.object = [@"變長編碼器和解碼器測試數據包20" dataUsingEncoding:NSUTF8StringEncoding];
[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];
req = [[RHSocketCustomRequest alloc] init];
req.fenGeFu = 0x24;
req.dataType = 0;
req.object = [@"變長編碼器和解碼器測試數據包300" dataUsingEncoding:NSUTF8StringEncoding];
[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationSocketPacketRequest object:req];
} else {
//
}//if
}
- (void)detectSocketPacketResponse:(NSNotification *)notif
{
NSLog(@"detectSocketPacketResponse: %@", notif);
//這裏結果，記得觀察打印的內容
NSDictionary *userInfo = notif.userInfo;
RHSocketCustomResponse *rsp = userInfo[@"RHSocketPacket"];
NSLog(@"detectSocketPacketResponse data: %@", [rsp object]);
NSLog(@"detectSocketPacketResponse string: %@", [[NSString alloc] initWithData:[rsp object] encoding:NSUTF8StringEncoding]);
}源碼RHSocketCustomCodecDemo已經上傳到github中，可以自行下載。
（demo中是通過pod引入RHSocketKit庫的，已經包含了Podfile文件，pod install後就可以正常運行）
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