iOS网络编程(六)NSURLSession详解

//
// HMTRootViewController.m
//
//
// Created by HMT on 14-6-7.
// Copyright (c) 2014年 胡明涛. All rights reserved.
//

import “HMTRootViewController.h”

import “HMTAppDelegate.h”

@interface HMTRootViewController ()

@property (nonatomic,strong)UIImageView *imageView;
@property (nonatomic,strong)UIProgressView *progressIndicator;

@property (nonatomic,strong)NSURLSession *urlSession; // 普通会话
//@property (nonatomic,strong)NSURLSession *backgroundSession; // 后台会话
@property (nonatomic,strong)NSURLSessionDownloadTask *sessionDownloadTask; // 下载Task
@property (nonatomic,strong)NSURLSessionDownloadTask *resumableTask; // 恢复下载Task
@property (nonatomic,strong)NSURLSessionDownloadTask *backgroundTask; // 后台下载Task
@property (nonatomic,strong)NSData *partialData; // 下载的局部数据

@end

@implementation HMTRootViewController

• (id)initWithNibName:(NSString )nibNameOrNil bundle:(NSBundle )nibBundleOrNil
  {
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
  // Custom initialization
  }
  return self;
  }

• (void)viewDidLoad{

  [super viewDidLoad];

  self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 64, 320, 300)];
  [self.view addSubview:_imageView];

  self.progressIndicator = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];
  _progressIndicator.frame = CGRectMake(50, 500, 220, 50);
  [self.view addSubview:_progressIndicator];

  UIButton *cancleButton = [UIButton buttonWithType:UIButtonTypeSystem];
  cancleButton.frame = CGRectMake(120, 400, 40, 40);
  [cancleButton setTitle:@”取消” forState:UIControlStateNormal];
  [cancleButton addTarget:self action:@selector(didClickCancleButtonAction:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:cancleButton];

  UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeSystem];
  downloadButton.frame = CGRectMake(20, 400, 40, 40);
  [downloadButton setTitle:@”下载” forState:UIControlStateNormal];
  [downloadButton addTarget:self action:@selector(didClickDownloadButtonAction:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:downloadButton];

  UIButton *uploadButton = [UIButton buttonWithType:UIButtonTypeSystem];
  uploadButton.frame = CGRectMake(70, 400, 40, 40);
  [uploadButton setTitle:@”上传” forState:UIControlStateNormal];
  [uploadButton addTarget:self action:@selector(didClickUploadButtonAction:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:uploadButton];

  UIButton *resumableButton = [UIButton buttonWithType:UIButtonTypeSystem];
  resumableButton.frame = CGRectMake(180, 400, 40, 40);
  [resumableButton setTitle:@”恢复” forState:UIControlStateNormal];
  [resumableButton addTarget:self action:@selector(didClickResuableButtonAction:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:resumableButton];

  UIButton *backgroundLoadButton = [UIButton buttonWithType:UIButtonTypeSystem];
  backgroundLoadButton.frame = CGRectMake(220, 400, 80, 40);
  [backgroundLoadButton setTitle:@”后台下载” forState:UIControlStateNormal];
  [backgroundLoadButton addTarget:self action:@selector(didClickBackgroundButtonAction:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:backgroundLoadButton];

  pragma mark - 如果我们需要利用NSURLSession进行数据传输我们需要：

  /**

  • 创建一个NSURLSessionConfiguration，用于创建NSSession时设置工作模式(3种)
  • (1)一般模式（default）：工作模式类似于原来的NSURLConnection，可以使用缓存的Cache，Cookie，鉴权。
  • (2)及时模式（ephemeral）：不使用缓存的Cache，Cookie，鉴权。
  • (3)后台模式（background）：在后台完成上传下载，创建Configuration对象的时候需要给一个NSString的ID用于追踪完成工作的Session是哪一个
    */
    NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];

  /**

  • @网络设置：参考NSURLConnection中的设置项
  • 两种创建方法(目前不太懂什么区别)
  • (1)就是根据刚才创建的Configuration创建一个Session，系统默认创建一个新的OperationQueue处理Session的消息
  • (2)可以设定回调的delegate（注意这个回调delegate会被强引用），并且可以设定delegate在哪个OperationQueue回调，如果我们将其
  • 设置为[NSOperationQueue mainQueue]就能在主线程进行回调非常的方便
    */
    //NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig];
    self.urlSession = [NSURLSession sessionWithConfiguration:sessionConfig delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    NSURL *url = [NSURL URLWithString:@”http://www.bizhiwa.com/uploads/allimg/2012-01/22021207-1-311536.jpg“];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];

  /**

  • NSURLSessionUploadTask：上传用的Task，传完以后不会再下载返回结果；
  • NSURLSessionDownloadTask：下载用的Task；
  • NSURLSessionDataTask：可以上传内容，上传完成后再进行下载。
    */
    self.sessionDownloadTask = [self.urlSession downloadTaskWithRequest:request];

  // 同NSURLConnection一样,有代理方法也就有block方法
  // [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
  // }];

}

pragma mark 点击下载

• (void)didClickDownloadButtonAction:(UIButton *)button{

  // 因为任务默认是挂起状态，需要恢复任务（执行任务）
  [_sessionDownloadTask resume];

}

pragma mark 点击上传

• (void)didClickUploadButtonAction:(UIButton *)button{

  //判断imageView是否有内容
  if (_imageView.image == nil) {

  NSLog(@"image view is empty");
  return;
  

  }

  // 0. 上传之前在界面上添加指示符
  UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
  // 设置位置???
  CGSize size = _imageView.bounds.size;
  indicator.center = CGPointMake(size.width / 2.0, size.height / 2.0);
  [self.imageView addSubview:indicator];
  [indicator startAnimating];

  // 1. URL
  NSURL *url = [NSURL URLWithString:@”http://www.bizhiwa.com/uploads/allimg/2012-01/22021207-1-311536.jpg“];

  // 2. Request -> PUT,request的默认操作是GET
  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:5.0f];
  request.HTTPMethod = @”PUT”;

  // * 设置网络请求的身份验证! *

  // 1> 授权字符串

  NSString *authStr = @”admin:123456”;

  // 2> BASE64的编码,避免数据在网络上以明文传输
  // iOS中,仅对NSData类型的数据提供了BASE64的编码支持
  NSData *authData = [authStr dataUsingEncoding:NSUTF8StringEncoding];
  NSString *encodeStr = [authData base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithCarriageReturn];
  NSString *authValue = [NSString stringWithFormat:@”Basic %@”, encodeStr];
  [request setValue:authValue forHTTPHeaderField:@”Authorization”];

  // 3. Session
  NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
  NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig delegate:self delegateQueue:[NSOperationQueue mainQueue]];

  // 4. UploadTask
  NSData *imageData = UIImageJPEGRepresentation(_imageView.image, 0.75);
  // 应用block的请求方式
  NSURLSessionUploadTask *uploadTask = [session uploadTaskWithRequest:request fromData:imageData completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

  // 上传完成后,data参数转换成string就是服务器返回的内容
  
  NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
  NSLog(@"OK -> %@", str);
  
  [NSThread sleepForTimeInterval:5.0f];
  
  dispatch_async(dispatch_get_main_queue(), ^{
  
      [indicator stopAnimating];
      [indicator removeFromSuperview];
  
  });
  

  }];

  // 因为任务默认是挂起状态，需要恢复任务（执行任务）
  [uploadTask resume];
  }

pragma mark 点击取消

// NSURLConnection一旦发送是没法取消的。但是，我们可以很容易的取消掉一个NSURLSessionTask任务
- (void)didClickCancleButtonAction:(UIButton *)button{

/**
 *  当取消后，会回调这个URLSession:task:didCompleteWithError:代理方法，通知你去及时更新UI。当取消一个任务后，也
 *  十分可能会再一次回调这个代理方法URLSession:downloadTask:didWriteData:BytesWritten:totalBytesExpectedToWrite:
 *  当然，didComplete 方法肯定是最后一个回调的。
 */

// if (_sessionDownloadTask) {
//
// // 取消下载请求
// [_sessionDownloadTask cancel];
// _sessionDownloadTask = nil;
// }

if (!self.sessionDownloadTask) {

    //  停止下载任务,把待恢复的数据保存到一个变量中，方便后面恢复下载使用
    [self.sessionDownloadTask cancelByProducingResumeData:^(NSData *resumeData) {

        self.partialData = resumeData;
        self.sessionDownloadTask = nil;

    }];
}

}

pragma mark 恢复下载(断点续传)

• (void)didClickResuableButtonAction:(UIButton *)button{

  if (self.partialData) {
  
      self.sessionDownloadTask = [self.urlSession downloadTaskWithResumeData:self.partialData];
      self.partialData = nil;
  
  }else{
  
      NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://pic4.duowan.com/wow/1002/130782267821/130782458426.jpg"]];
      self.resumableTask = [self.urlSession downloadTaskWithRequest:request];
  
  }
  
  [self.sessionDownloadTask resume];
  

}

pragma mark 后台下载模式

• (void)didClickBackgroundButtonAction:(UIButton *)button{

  NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@”http://dldir1.qq.com/qqfile/QQforMac/QQ_V3.1.2.dmg”]];
  self.backgroundTask = [[self backgroundSession] downloadTaskWithRequest:request];

  [self.backgroundTask resume];
  }

pragma mark - NSURLSessionDownloadTaskDelegate

// 下载完成
- (void)URLSession:(NSURLSession )session downloadTask:(NSURLSessionDownloadTask )downloadTask didFinishDownloadingToURL:(NSURL *)location{

/**
  *******->appDelegete里面的方法
 typedef void(^MyBlock)();
 @property (copy, nonatomic) MyBlock backgroundURLSessionCompletionHandler;
 //  后台请求结束时调用的方法
 - (void)application:(UIApplication *)application handleEventsForBackgroundURLSession:(NSString *)identifier completionHandler:(void (^)())completionHandler{

 self.backgroundURLSessionCompletionHandler = completionHandler;
 }

 */
//  如果是后台NSURLSession,后台请求结束后会调用这个方法,通知你应该更新UI了
if (session == [self backgroundSession]) {

    self.backgroundTask = nil;
    HMTAppDelegate *appDelegate = (HMTAppDelegate *)[UIApplication sharedApplication].delegate;
    if (appDelegate.backgroundURLSessionCompletionHandler) {

        void(^handler)() = appDelegate.backgroundURLSessionCompletionHandler;
        appDelegate.backgroundURLSessionCompletionHandler = nil;
        handler();
    }

}

//  这里的缓存处理做的不好,大家按自己的方法处理就行,还有图片的存储以它本身的URL路径为准,这样是不会有重复的
NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *cachesURLPath = [[fileManager URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject];
//  根据URL获取到下载的文件名,拼接成沙盒的存储路径(location是下载的临时文件目录,在tmp文件夹里面)
NSURL *destinationPath = [cachesURLPath URLByAppendingPathComponent:[location lastPathComponent]];

NSError *error = nil;
BOOL success = [fileManager moveItemAtURL:location toURL:destinationPath error:&error];
[fileManager removeItemAtURL:location error:NULL];

//  location是下载的临时文件目录,将文件从临时文件夹复制到沙盒

// BOOL success = [fileManager copyItemAtURL:location toURL:destinationPath error:&error];
if (success) {

    dispatch_async(dispatch_get_main_queue(), ^{

        UIImage *image = [UIImage imageWithContentsOfFile:[destinationPath path]];
        self.imageView.image = image;
        //  UIImageView会自动裁剪图片适应它的frame,下面这个属性就是展示原图
        self.imageView.contentMode = UIViewContentModeScaleAspectFill;

    });
}

}

// 不管任务是否成功，在完成后都会回调这个代理方法
- (void)URLSession:(NSURLSession )session task:(NSURLSessionTask )task didCompleteWithError:(NSError *)error{

//  如果error是nil，则证明下载是成功的，否则就要通过它来查询失败的原因。如果下载了一部分，这个error会包含一个NSData对象，如果后面要恢复任务可以用到
if (error == nil) {

    dispatch_async(dispatch_get_main_queue(), ^{

        self.progressIndicator.hidden = YES;
    });
}

}

// 传输进度
- (void)URLSession:(NSURLSession )session downloadTask:(NSURLSessionDownloadTask )downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{

double currentValue = totalBytesWritten / (double)totalBytesExpectedToWrite;
dispatch_async(dispatch_get_main_queue(), ^{
    NSLog(@"%f",currentValue);
    self.progressIndicator.hidden = NO;
    self.progressIndicator.progress = currentValue;
});

}

// 未知
- (void)URLSession:(NSURLSession )session downloadTask:(NSURLSessionDownloadTask )downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{

}

pragma mark - NSURLSession另一个重要的特性：即使当应用不在前台时，你也可以继续传输任务。当然，我们的会话模式也要为后台模式

• (NSURLSession *)backgroundSession{

  // 通过给的后台token，我们只能创建一个后台会话，所以这里使用dispatch once block
  static NSURLSession *backgroundSession = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{

  NSURLSessionConfiguration *config = [NSURLSessionConfiguration backgroundSessionConfiguration:@"com.shinobicontrols.BackgroundDownload.BackgroundSession"];
  backgroundSession = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
  

  });

  return backgroundSession;
  }

• (void)didReceiveMemoryWarning
  {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

/*

pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/

@end