IOS-网络（NSURLSession）

 一、NSURLSession的基本用法

//
//  ViewController.m
//  NSURLSession
//
//  Created by ma c on 16/2/1.
//  Copyright © 2016年 博文科技. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDownloadDelegate>

@end

@implementation ViewController
/*
 任务：任何请求都是一个任务
 
 NSURLSessionDataTask:普通的GET、POST请求
 NSURLSessionDownloadTask:文件下载
 NSURLSessionUploadTask:文件上传
 
 注意：如果给下载任务设置了completionHandler这个block，也实现了下载代理方法，优先执行block

 */
- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor cyanColor];

}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
//    [self sendGetRequest];
//    [self sendPostRequest];
//    [self downlaodTask1];
    [self downlaodTask2];
}

#pragma mark - NSURLSessionDownloadTask2
///下载任务（有下载进度）
- (void)downlaodTask2
{
    //1.创建Session对象
    NSURLSessionConfiguration *cfg = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:cfg delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    //2.创建一个任务
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/minion_02.mp4"];
    NSURLSessionDownloadTask *task = [session downloadTaskWithURL:url];
    //3.开始任务
    [task resume];
}

#pragma mark - NSURLSessionDownloadDelegate的代理方法
///下载完毕时调用
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
    NSLog(@"didFinishDownloadingToURL--->%@",location);
    //location：文件的临时路径，下载好的文件
    NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, nil) lastObject];
    NSString *file = [caches stringByAppendingPathComponent:downloadTask.response.suggestedFilename];
    
    //降临时文件夹，剪切或者复制到Caches文件夹
    NSFileManager *mgr = [NSFileManager defaultManager];
    [mgr moveItemAtPath:location.path toPath:file error:nil];
}
///恢复下载时调用
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
    
}
///每当写完一部分就调用（根据文件大小调用多次）
//bytesWritten:             这次调用写了多少
//totalBytesWritten:        累计写了多少长度到沙河中
//totalBytesExpectedToWrite:文件的总长度
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
    double progress = (double)totalBytesWritten / totalBytesExpectedToWrite;
    
    NSLog(@"下载进度--->%lf",progress);
    
}

#pragma mark - NSURLSessionDownloadTask1
///下载任务（不能看到下载进度）
- (void)downlaodTask1
{
    //1.创建Session对象
    NSURLSession *session = [NSURLSession sharedSession];
    //2.创建NSURL
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/minion_02.mp4"];
    NSURLSessionDownloadTask *task = [session downloadTaskWithURL:url completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {
       //location：文件的临时路径，下载好的文件
        NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, nil) lastObject];
        NSString *file = [caches stringByAppendingPathComponent:response.suggestedFilename];
        
        //降临时文件夹，剪切或者复制到Caches文件夹
        NSFileManager *mgr = [NSFileManager defaultManager];
        [mgr moveItemAtPath:location.path toPath:file error:nil];
        
        //[mgr copyItemAtPath:location.path toPath:file error:nil];
        
        
    }];
    //3.开始任务
    [task resume];
}


#pragma mark - NSURLSessionDataTask
///POST请求
- (void)sendPostRequest
{
    //1.创建Session对象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //2.创建NSURL
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/login"];
    //3.创建请求
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    //4.设置请求体
    request.HTTPBody = [@"username=123&pwd=123" dataUsingEncoding:NSUTF8StringEncoding];
    //5.创建一个任务
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data
                                                             options:NSJSONReadingMutableLeaves error:nil];
        NSLog(@"sendPostRequest:%@",dict);
    }];
    //6.开始任务
    [task resume];
}

///GET请求
- (void)sendGetRequest
{
    //1.得到session对象
    NSURLSession *session = [NSURLSession sharedSession];
    //2.创建一个任务
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/video"];
    NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data
                                                             options:NSJSONReadingMutableLeaves error:nil];
        NSLog(@"sendGetRequest:%@",dict);
    }];
    //3.开始任务
    [task resume];
}
@end

 二、NSURLSession的断点续传

//
//  ViewController.m
//  IOS_0204_NSURLSession断点续传
//
//  Created by ma c on 16/2/4.
//  Copyright © 2016年 博文科技. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDownloadDelegate>

- (IBAction)btnClick:(UIButton *)sender;
@property (weak, nonatomic) IBOutlet UIButton *btnClick;
@property (weak, nonatomic) IBOutlet UIProgressView *progressView;

@property (nonatomic, strong) NSURLSessionDownloadTask *task;
@property (nonatomic, strong) NSData *resumeData;
@property (nonatomic, strong) NSURLSession *session;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.progressView.progress = 0.01;
}

- (NSURLSession *)session
{
    if (!_session) {
        //获得session
        NSURLSessionConfiguration *cfg = [NSURLSessionConfiguration defaultSessionConfiguration];
        _session = [NSURLSession sessionWithConfiguration:cfg delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    }
    return _session;
}


- (IBAction)btnClick:(UIButton *)sender {
    //取反
    sender.selected = !sender.isSelected;
    
    if (sender.selected) { //开始、恢复下载
        
        if (self.resumeData) { //恢复下载
            [self resume];
            
        } else {  //开始下砸
            [self start];
        }
        
    } else { //暂停下载
        [self pause];
    }
}
//从零开始下载
- (void)start
{
    //1.创建一个下载任务
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/minion_01.mp4"];
    self.task = [self.session downloadTaskWithURL:url];
    //2.开始任务
    [self.task resume];
}
//继续下载
- (void)resume
{
    //传入上次暂停下载返回的数据，就可以恢复下载
    self.task = [self.session downloadTaskWithResumeData:self.resumeData];
    
    [self.task resume];
}
//暂停下载
- (void)pause
{
    __weak typeof(self) vc = self;
    [self.task cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
        
        //resumeData:包含了下载的开始位置
        vc.resumeData = resumeData;
        vc.task = nil;
        
    }];
}
#pragma mark - NSURLSessionDownloadDelegate的代理方法
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
    self.btnClick.selected = !self.btnClick.isSelected;
    
    NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
    //suggestedFilename建议使用的文件名，一般与服务器端的文件名一致
    NSString *file = [caches stringByAppendingPathComponent:downloadTask.response.suggestedFilename];
    //NSLog(@"%@",file);
    NSFileManager *mgr = [NSFileManager defaultManager];
    //将临时文件复制或者剪切到caches文件夹
    [mgr moveItemAtPath:location.path toPath:file error:nil];
    
}

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
    
}

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
    //获得下载进度
    self.progressView.progress = (double)totalBytesWritten / totalBytesExpectedToWrite;
}
@end