Question

我开发的应用程序是与OS X服务器通信的iOS客户端。该应用程序的当前版本执行主线程上的所有网络逻辑，这适用于我想要做的事情。

但是，在下一个版本中，我希望网络逻辑更加灵活。为了实现这个目标，我想为它提供一个单独的线程，但我不太确定哪种解决方案适合我的需求。

起初，GCD看起来是一个很好的候选者，但它似乎只适合在一个单独的线程上执行的大量工作。我想要做的是将所有网络逻辑放在一个单独的线程上。 iOS客户端和OS X服务器之间的连接是持久的，所有数据流和处理应该在该单独的线程上进行。

问题归结为，哪种方法最适合这种情况？

编辑：为了摆脱任何混淆，我使用的连接使用套接字和NSStream实例。我不是在处理连接到远程Web服务器。换句话说，AFNetworking和ASIHttpRequest对我来说不是一个选择。

Answer 1

您可以使用runloop创建一个线程（我们称之为NetworkThread），运行以下代码：

while (!self.isCancelled) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
    [pool release];
}

然后您可以使用- (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(id)arg waitUntilDone:(BOOL)wait在NetworkThread上执行网络请求选择器。
将在NetworkThread上调用所有网络回调，然后在NetworkThread上处理您的响应数据，将最终数据推送到主线程，更新UI。

Answer 2

AFNetworking很棒。使用块和GCD。我编写了一个NetworkClient类，使得调用它非常简单。随意使用或自定义它，但我不保证任何东西：）

如果不符合您的需求，可以删除API密钥。我添加它作为一种为我的所有网络请求添加安全性的方法。我的Web服务在返回任何内容之前检查传入的APIKey的有效性。

此外，您可以非常灵活地完成工作。您可以执行同步或异步请求，不会在发生故障时警告用户的请求等。

基本示例用法：

NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                                @"GetAllParkingLots", @"Command",
                                nil];

        [NetworkClient processURLRequestWithURL:nil andParams:params block:^(id obj) {
            // I check to see what kind of object is passed back, in this case I was expecting an Array
            if ([obj isKindOfClass:[NSArray class]]) {
                // Do something with the Array
                [self processNetworkRequestWithArray:(NSArray *)obj];
            }
        }];

NetworkClient.h：

//
//  NetworkClient.h
//
//  Created by LJ Wilson on 2/18/12.
//  Copyright (c) 2012 LJ Wilson All rights reserved.
//

#import <Foundation/Foundation.h>

extern NSString * const APIKey;

@interface NetworkClient : NSObject

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                          block:(void (^)(id obj))block;

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
                          block:(void (^)(id obj))block;

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
             alertUserOnFailure:(BOOL)alertUserOnFailure
                          block:(void (^)(id obj))block;

+(void)handleNetworkErrorWithError:(NSError *)error;

+(void)handleNoAccessWithReason:(NSString *)reason;

@end

NetworkClient.m：

//
//  NetworkClient.m
//
//  Created by LJ Wilson on 2/18/12.
//  Copyright (c) 2012 LJ Wilson All rights reserved.
//

#import "NetworkClient.h"
#import "AFHTTPClient.h"
#import "AFHTTPRequestOperation.h"
#import "SBJson.h"

#warning Set APIKey or set to nil
NSString * const APIKey = @"YourAPIKEYGoesHere";

@implementation NetworkClient

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                          block:(void (^)(id obj))block {

    [self processURLRequestWithURL:url andParams:params syncRequest:NO alertUserOnFailure:NO block:^(id obj) {
        block(obj);
    }];
}

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
                          block:(void (^)(id obj))block {
    [self processURLRequestWithURL:url andParams:params syncRequest:syncRequest alertUserOnFailure:NO block:^(id obj) {
        block(obj);
    }];
}


+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
             alertUserOnFailure:(BOOL)alertUserOnFailure
                          block:(void (^)(id obj))block {

#warning Fix default url
    // Default url goes here, pass in a nil to use it
    if (url == nil) {
        url = @"YourDefaultURLGoesHere";
    }

    NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithDictionary:params];
    [dict setValue:APIKey forKey:@"APIKey"];

    NSDictionary *newParams = [[NSDictionary alloc] initWithDictionary:dict];

    NSURL *requestURL;
    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:requestURL];

    NSMutableURLRequest *theRequest = [httpClient requestWithMethod:@"POST" path:url parameters:newParams];

    __block NSString *responseString = @"";

    AFHTTPRequestOperation *_operation = [[AFHTTPRequestOperation alloc] initWithRequest:theRequest];
    __weak AFHTTPRequestOperation *operation = _operation;

    [operation  setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        responseString = [operation responseString];

        id retObj = [responseString JSONValue];

        // Check for invalid response (No Access)
        if ([retObj isKindOfClass:[NSDictionary class]]) {
            if ([[(NSDictionary *)retObj valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                block(nil);
                [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
            }
        } else if ([retObj isKindOfClass:[NSArray class]]) {
            if ([(NSArray *)retObj count] > 0) {
                NSDictionary *dict = [(NSArray *)retObj objectAtIndex:0];
                if ([[dict valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                    block(nil);
                    [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
                }
            }
        }
        block(retObj);
    } 
                                      failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                                          NSLog(@"Failed with error = %@", [NSString stringWithFormat:@"[Error]:%@",error]);
                                          block(nil);
                                          if (alertUserOnFailure) {
                                              // Let the user know something went wrong
                                              [self handleNetworkErrorWithError:operation.error];
                                          }

                                      }];

    [operation start];

    if (syncRequest) {
        // Process the request syncronously
        [operation waitUntilFinished];
    } 


}


+(void)handleNetworkErrorWithError:(NSError *)error {
    NSString *errorString = [NSString stringWithFormat:@"[Error]:%@",error];

    // Standard UIAlert Syntax
    UIAlertView *myAlert = [[UIAlertView alloc] 
                            initWithTitle:@"Connection Error" 
                            message:errorString 
                            delegate:nil 
                            cancelButtonTitle:@"OK" 
                            otherButtonTitles:nil, nil];

    [myAlert show];

}

+(void)handleNoAccessWithReason:(NSString *)reason {
    // Standard UIAlert Syntax
    UIAlertView *myAlert = [[UIAlertView alloc] 
                            initWithTitle:@"No Access" 
                            message:reason 
                            delegate:nil 
                            cancelButtonTitle:@"OK" 
                            otherButtonTitles:nil, nil];

    [myAlert show];

}


@end

在iOS上使用单独的线程进行联网

2 个答案: