Question

我正在使用连接到简单c套接字服务器的NSStreams创建聊天应用程序。流成功连接并发送数据，但无法接收数据。这是我使用NSStreams的Socket类：

socket.h中

@interface Socket : NSObject <NSStreamDelegate>

- (void)connectToServerWithIP:(NSString *)ip andPort:(int)port;
- (NSString *)sendMessage:(NSString *)outgoingMessage;

@end

Socket.m

#import "Socket.h"

@interface Socket ()

@property (strong, nonatomic) NSInputStream *inputStream;
@property (strong, nonatomic) NSOutputStream *outputStream;
@property (strong, nonatomic) NSString *output;

@end

@implementation Socket

@synthesize inputStream;
@synthesize outputStream;
@synthesize output;

- (void)connectToServerWithIP:(NSString *)ip andPort:(int)port
{
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)ip, port, &readStream, &writeStream);
    inputStream = (__bridge_transfer NSInputStream *)readStream;
    outputStream = (__bridge_transfer NSOutputStream *)writeStream;
    [inputStream setDelegate:self];
    [outputStream setDelegate:self];
    [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [inputStream open];
    [outputStream open];
}

- (NSString *)sendMessage:(NSString *)outgoingMessage
{
    NSData *messageData = [outgoingMessage dataUsingEncoding:NSUTF8StringEncoding];
    const void *bytes = [messageData bytes];
    uint8_t *uint8_t_message = (uint8_t*)bytes;
    [outputStream write:uint8_t_message maxLength:strlen([outgoingMessage cStringUsingEncoding:[NSString defaultCStringEncoding]])];
    while (![inputStream hasBytesAvailable]) {
        usleep(10);
    }
    uint8_t buffer[1024];
    [inputStream read:buffer maxLength:1023];
    NSString *outputString = [NSString stringWithUTF8String:(char *)buffer];
    return outputString;
}

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {
    NSLog(@"Stream Event: %lu", streamEvent);

    switch (streamEvent) {
        case NSStreamEventOpenCompleted:
            NSLog(@"Stream opened");
            break;
        case NSStreamEventHasBytesAvailable:
            if (theStream == inputStream) {
                uint8_t buffer[1024];
                long len;
                while ([inputStream hasBytesAvailable]) {
                    len = [inputStream read:buffer maxLength:sizeof(buffer)];
                    if (len > 0) {
                        output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSASCIIStringEncoding];
                        if (output) {
                            NSLog(@"Data: %@", output);
                        }
                    }
                }
            }
            break;
        case NSStreamEventErrorOccurred:
            NSLog(@"Can not connect to the host!");
            break;
        case NSStreamEventEndEncountered:
            [theStream close];
            [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            theStream = nil;
            break;
        default:
            NSLog(@"Unknown event");
    }
}

@end

ChatViewController.m

//
//  ChatViewController.m
//  Chat
//
//  Created by James Pickering on 10/5/13.
//  Copyright (c) 2013 James Pickering. All rights reserved.
//

#import "ChatViewController.h"
#import "LoginViewController.h"
#import "StatusView.h"

@interface ChatViewController ()

@property (strong) IBOutlet NSTableView *people;
@property (strong) IBOutlet NSTextField *message;
@property (strong) IBOutlet NSButton *send;
@property (strong) IBOutlet NSButton *loginButton;
@property (strong) IBOutlet NSButton *settingsButton;
@property (strong) IBOutlet NSButton *panicButton;

@property (strong, nonatomic) NSString *recievedText;
@property (strong, nonatomic) NSMutableArray *tableData;
@property (strong, nonatomic) NSInputStream *inputStream;
@property (strong, nonatomic) NSOutputStream *outputStream;


- (void)openChat:(id)sender;

- (IBAction)panic:(id)sender;
- (IBAction)loginToChat:(id)sender;

@end

@implementation ChatViewController

@synthesize sock;
@synthesize recievedText;
@synthesize inputStream;
@synthesize outputStream;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.isLoggedIn = FALSE;
        sock = [[Socket alloc] init];
        [sock connectToServerWithIP:@"127.0.0.1" andPort:5001];
        //[self updateUI];
    }
    return self;
}

- (void)updateUI
{
    if (self.isLoggedIn) {
        recievedText = [sock sendMessage:@"getPeople"];
        self.tableData = [[NSMutableArray alloc] initWithArray:[recievedText componentsSeparatedByString:@";"]];
        NSLog(@"%@", self.tableData);
        [self.people reloadData];
    }
}

- (void)openChat:(id)sender
{
    NSLog(@"tru");
}

- (IBAction)panic:(id)sender {

}

- (IBAction)loginToChat:(id)sender {
    NSLog(@"Called");
    if (self.loginPopover == nil) {
        NSLog(@"Login Popover is nil");
        self.loginPopover = [[NSPopover alloc] init];
        self.loginPopover.contentViewController = [[LoginViewController alloc] initWithNibName:@"LoginViewController" bundle:nil];
    }
    if (!self.loginPopover.isShown) {
        NSLog(@"Login Popover is opening");
        [self.loginButton setTitle:@"Cancel"];
        [self.settingsButton setEnabled:NO];
        [self.send setEnabled:NO];
        [self.message setEnabled:NO];
        [self.loginPopover showRelativeToRect:self.loginButton.frame ofView:self.view preferredEdge:NSMinYEdge];
    }
    else {
        NSLog(@"Login Popover is closing");
        [self.loginButton setTitle:@"Login"];
        [self.settingsButton setEnabled:YES];
        [self.send setEnabled:YES];
        [self.message setEnabled:YES];
        [self.loginPopover close];
    }
}

- (NSInteger)numberOfRowsInTableView:(NSTableView *)aTableView
{
    return [self.tableData count];
}

- (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
    return [self.tableData objectAtIndex:rowIndex];
}

- (BOOL)canBecomeKeyWindow
{
    return YES;
}

- (BOOL)loginWithUsername:(NSString *)username andPassword:(NSString *)password
{
    // Error happens here

    recievedText = [sock sendMessage:@"login"];
    if ([recievedText isEqualToString:@"roger"]) {
        recievedText = [sock sendMessage:[NSString stringWithFormat:@"%@;%@", username, password]];
        if ([recievedText isEqualToString:@"access granted"]) {
            return YES;
        }
        else {
            return NO;
        }
    }
    else {
        return NO;
    }
}

@end

问题是它永远挂在这一行代码上：while (![inputStream hasBytesAvailable]) {}，但我不明白为什么。服务器应该发回消息。

Answer 1

因此，查看您的NSStreamDelegate，看起来您还没有实现该switch语句的所有案例。我最近为OS X写了一个IRC客户端，它以非常类似的方式使用NSStream和NSStreamDelegate，我很确定编译器应该在你没有检查过时抱怨所有案件都在那里。

回顾some of my code看起来你应该检查案例

NSStreamEventHasSpaceAvailable
NSStreamEventOpenCompleted
NSStreamEventHasBytesAvailable
NSStreamEventEndEncountered
NSStreamEventErrorOccurred

因此，您尚未检查的情况为NSStreamEventHasSpaceAvailable，即您可以开始写入您的信息流。

编辑：再次阅读您的代码，我在您的sendMessage操作中看到您正在使用outputStream对象而不是代理进行编写，然后自己完成工作以阅读inputStream。我想您可能想要使用委托，而不是直接从您的输入流中读取，因为它将极大地简化您的代码从网络接收数据的方式。据我所知，NSStream是围绕数据从网络缓冲这一事实提供一小层抽象，因此您不需要在输入流时调用usleep这样的事情没有可供读取的字节。

edit2：我看到了有关您的代码永远不会超过while (![inputStream hasBytesAvailable])的更新，而且很明显问题是您没有正确使用您的流。我看到它的方式，使用NSStream的最佳方法是使用其handleEvent:(NSStreamEvent) event方法响应事件，并且永远不会直接告诉它写入字节，或者在它有可用字节之前休眠。 / p>

在我链接到你的代码中，我有一个readDelegate和一个处理NSStreams的writeDelegate，你可能想看看我如何使用我的writeDelegate here。我基本上有一个方法addCommand:(NSString *) command，它将一个字符串写入队列中，然后当我的流委托写入字节（NSStreamEventHasSpaceAvailable）时，我尽可能多地写入字节。我希望这有帮助！

NSStream无法接收数据

1 个答案: