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iOS 网络 NSURLSession

NSURLSession

使用步骤

创建NSURLSession
创建Task
执行Task

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self post];
}
//get第一种
- (void)get
{
    NSLog(@"%s", __func__);
    
    NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/login?username=xxxxxxxx&pwd=xxxxxxxx&type=JSON"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    // 1.创建NSURLSession
    NSURLSession *session = [NSURLSession sharedSession];
    // 2.利用NSURLSession创建Task
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        /*
         data: 服务器返回给我们的数据
         response : 响应头
         error: 错误信息
         */
        NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    // 3.执行Task
    [task resume];
}
//get第二种
- (void)get2
{
    NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/login?username=xxxxxxxx&pwd=xxxxxxxx&type=JSON"];
    
    // 1.创建NSURLSession
    NSURLSession *session = [NSURLSession sharedSession];
    // 2.利用NSURLSession创建Task
    // 如果是通过传入url的方法创建Task, 方法内部会自动根据URL创建一个Request
    // 如果是发送Get请求, 或者不需要设置请求头信息, 那么建议使用当前方法发送请求
    NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    // 3.执行Task
    [task resume];
}
//第三种使用方式 post
- (void)post
{
    NSURL *url = [NSURL URLWithString:@"xxxxxxxx/login"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    request.HTTPBody = [@"username=xxxxxxxx&pwd=xxxxxxxx&type=JSON" dataUsingEncoding:NSUTF8StringEncoding];
    
    // 1.创建NSURLSession
    NSURLSession *session = [NSURLSession sharedSession];
    // 2.利用NSURLSession创建Task
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
         NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    // 3.执行Task
    [task resume];
    
}

NSURLSessionDataTask

   NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/login?username= xxxxxxxx&pwd= xxxxxxxx"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    // 1.获得NSURLSession对象
    NSURLSession *session = [NSURLSession sharedSession];

    // 2.创建任务
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];

    // 3.启动任务
    [task resume];
    NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/login?username= xxxxxxxx&pwd= xxxxxxxx"];
    // 1.获得NSURLSession对象
    NSURLSession *session = [NSURLSession sharedSession];

    // 2.创建任务
    NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
         NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    // 3.启动任务
    [task resume];

POST

 NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/login"];
    // 设置请求头
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    request.HTTPBody = [@"username= xxxxxxxx&pwd= xxxxxxxx" dataUsingEncoding:NSUTF8StringEncoding];

    // 1.获得NSURLSession对象
    NSURLSession *session = [NSURLSession sharedSession];

    // 2.创建任务
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    // 3.启动任务
    [task resume];

NSURLSessionDataDelegate代理注意事项

Task都是通过Session监听

// 1.获得NSURLSession对象
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]];

NSURLSessionDataDelegate默认不会接受数据

/**
 * 1.接收到服务器的响应
 */
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    NSLog(@"%s", __func__);
    NSLog(@"%@", [NSThread currentThread]);
    /*
     NSURLSessionResponseAllow: 去向处理服务器响应, 内部会调用[task cancle]
     NSURLSessionResponseCancel: 允许处理服务器的响应，才会继续接收服务器返回的数据
     NSURLSessionResponseBecomeDownload: 讲解当前请求变为下载
     */
    completionHandler(NSURLSessionResponseAllow);
}
/**
 * 2.接收到服务器的数据（可能会被调用多次）
 */
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{
    NSLog(@"%s", __func__);
}
/**
 * 3.请求成功或者失败（如果失败，error有值）
 */
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"%s", __func__);
}

NSURLSessionDownloadTask

DownloadTask默认已经实现边下载边写入

// 1.创建request
  NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx/resources/videos/minion_01.mp4"];
  NSURLRequest *request = [NSURLRequest requestWithURL:url];

  // 2.创建session
  NSURLSession *session = [NSURLSession sharedSession];

  // 3.创建下载任务
  NSURLSessionDownloadTask *task = [session downloadTaskWithRequest:request completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {
      NSLog(@"%@", location.absoluteString);

      NSFileManager *manager = [NSFileManager defaultManager];
      NSString *toPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
      toPath = [toPath stringByAppendingPathComponent:response.suggestedFilename];
      // 将下载好的文件从location移动到cache
      [manager moveItemAtURL:location toURL:[NSURL fileURLWithPath:toPath] error:nil];
  }];

  // 4.开启下载任务
  [task resume];

DownloadTask断点下载

暂停: suspend
继续: resume
取消: cancel
任务一旦被取消就无法恢复
区别并返回下载信息

//取消并获取当前下载信息
[self.task cancelByProducingResumeData:^(NSData *resumeData) {
  self.resumeData = resumeData;
}];

// 根据用户上次的下载信息重新创建任务
self.task = [self.session downloadTaskWithResumeData:self.resumeData];
[self.task resume];

DownloadTask监听下载进度

/**
 * 每当写入数据到临时文件时，就会调用一次这个方法
 * totalBytesExpectedToWrite:总大小
 * totalBytesWritten: 已经写入的大小
 * bytesWritten: 这次写入多少
 */
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
    NSLog(@"正在下载: %.2f", 1.0 * totalBytesWritten / totalBytesExpectedToWrite);
}

/*
 * 根据resumeData恢复任务时调用
 * expectedTotalBytes:总大小
 * fileOffset: 已经写入的大小
 */
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
    NSLog(@"didResumeAtOffset fileOffset = %lld , expectedTotalBytes = %lld", fileOffset, expectedTotalBytes);
}
/**
 * 下载完毕就会调用一次这个方法
 */
- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
    NSLog(@"下载完毕");
    // 文件将来存放的真实路径
    NSString *file = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename];

    // 剪切location的临时文件到真实路径
    NSFileManager *mgr = [NSFileManager defaultManager];
    [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:file] error:nil];
}
/**
 * 任务完成
 */
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"didCompleteWithError");
}

离线断点下载

使用NSURLSessionDataTask

NSMutableURLRequest *reuqest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://xxxxxxxx/resources/videos/minion_01.mp4"]];
// 核心方法, 实现从指定位置开始下载
NSInteger currentBytes = KCurrentBytes;
NSString *range = [NSString stringWithFormat:@"bytes=%zd-", currentBytes];
[reuqest setValue:range forHTTPHeaderField:@"Range"];

// 核心方法, 自己实现边下载边写入
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data;

NSURLSessionUploadTask

设置设置请求头, 告诉服务器是文件上传
- multipart/form-data; boundary=lnj
必须自己严格按照格式拼接请求体

请求体不能设置给request, 只能设置给fromData

The body stream and body data in this request object are ignored. +

[[self.session uploadTaskWithRequest:request fromData:body completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
  NSLog(@"%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
}] resume];

注意:以下方法用于PUT请求

[self.session uploadTaskWithRequest:<#(nonnull NSURLRequest *)#> fromFile:<#(nonnull NSURL *)#>]

监听上传进度

/*
 bytesSent: 当前发送的文件大小
 totalBytesSent: 已经发送的文件总大小
 totalBytesExpectedToSend: 需要发送的文件大小
 */
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend
{
    NSLog(@"%zd, %zd, %zd", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"%s", __func__);
}

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原文地址：https://www.cnblogs.com/liujiaoxian/p/4892763.html