断点下载与文件上传

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 2017/06/20   Share

本篇博文的所有网络操作的对象都是一张图片。

普通下载

使用NSURLSessionDownloadTask实现。代码如下：

@interface DownloadController ()<NSURLSessionDownloadDelegate>

@end

static NSString *const ImageURL = @"https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1603118011167&di=fd9df24b9d887970aed9a6ec147d40da&imgtype=0&src=http%3A%2F%2Fimg.pconline.com.cn%2Fimages%2Fupload%2Fupc%2Ftx%2Fwallpaper%2F1209%2F05%2Fc0%2F13630426_1346827472062.jpg";

@implementation DownloadController {
    NSString *_fullPath;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    NSString *fileName = @"smile.png"; // 文件名称 通常需要通过md5生成一个唯一文件名
    NSString *docuPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    _fullPath = [docuPath stringByAppendingPathComponent:fileName];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self loadImage];
}

- (void)loadImage {
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:ImageURL]];
    request.HTTPMethod = @"GET";
    // ephemeralSessionConfiguration 不带缓存 defaultSessionConfiguration带缓存
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:nil];
    // NSURLSessionDownloadTask把数据直接下载到沙盒下tmp目录中
    NSURLSessionDownloadTask *task = [session downloadTaskWithRequest:request];
    [task resume];
}

#pragma mark - NSURLSessionDelegate
//1 响应头  这次网络数据的属性（下载的总数据大小 content-Length, Content-Type）
// 响应的过滤
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
    
    completionHandler(NSURLSessionResponseAllow);
}

// 下载过程 下载的进度 接收数据回掉
// 下载的数据自动写入沙盒下tmp目录中，未下载完的文件会一直保存，下载完成的话，会自动从目录中移除。
- (void)URLSession:(NSURLSession *)session
      downloadTask:(NSURLSessionDownloadTask *)downloadTask
      didWriteData:(int64_t)bytesWritten
 totalBytesWritten:(int64_t)totalBytesWritten
totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite {
    // bytesWritten 当前包收到的数据 totalBytesWritten已经接受的数据 totalBytesExpectedToWrite总数据大小
    NSLog(@"当前包收到的数据:%lld", bytesWritten);
    NSLog(@"已经接收到的总数据:%lld", totalBytesWritten);
    NSLog(@"需接收的总数据:%lld", totalBytesExpectedToWrite);
}

// 文件下载完成
// @param location 文件下载到沙盒下tmp目录中，系统会自动清理
- (void)URLSession:(NSURLSession *)session
      downloadTask:(NSURLSessionDownloadTask *)downloadTask
didFinishDownloadingToURL:(NSURL *)location {
    NSError *error = nil;
    [[NSFileManager defaultManager] moveItemAtURL:location toURL:[NSURL fileURLWithPath:_fullPath] error:&error];
}

// 网络任务结束
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
    
}

运行代码之后，在沙盒的Document目录中会有smile.png的图片，表示下载成功了。

注意： NSURLSessionDownloadTask下载的数据自动写入沙盒下tmp目录中，未下载完的文件会一直保存，下载完成的话，会自动移除。所以一定要在下载完成时刻把文件移动到目标路径下，否则文件就被移除了。

断点下载

断点下载的流程如下图
network1

断点下载原理：在网络请求之前，先获取本地已下载数据的size，配置请求头Range。如下代码所示

@interface BreakDownloadController ()<NSURLSessionTaskDelegate>

@end

static NSString *const ImageURL = @"https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1603118011167&di=fd9df24b9d887970aed9a6ec147d40da&imgtype=0&src=http%3A%2F%2Fimg.pconline.com.cn%2Fimages%2Fupload%2Fupc%2Ftx%2Fwallpaper%2F1209%2F05%2Fc0%2F13630426_1346827472062.jpg";

@implementation BreakDownloadController {
    NSString *_filePathDocument;
    NSOutputStream *_outputStream;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    NSString *fileName = @"smile";
    NSString *filePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    _filePathDocument = [filePath stringByAppendingPathComponent:fileName];
    _outputStream = [[NSOutputStream alloc] initToFileAtPath:_filePathDocument append:YES];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self loadImage];
}

- (void)loadImage {
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:ImageURL]];
    request.HTTPMethod = @"GET";
    NSDictionary *fileInfo = [[NSFileManager defaultManager] attributesOfItemAtPath:_filePathDocument error:nil];
    long filesize = [[fileInfo objectForKey:NSFileSize] longValue];
    [request setValue:[NSString stringWithFormat:@"bytes=%ld-", filesize] forHTTPHeaderField:@"Range"];
    
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:nil];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request];
    [task resume];
}

#pragma mark - NSURLSessionDelegate
// 响应的过滤
- (void)URLSession:(NSURLSession *)session
          dataTask:(NSURLSessionDataTask *)dataTask
didReceiveResponse:(NSURLResponse *)response
 completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler {
    [_outputStream open];
    completionHandler(NSURLSessionResponseAllow);
}

// 数据接收
- (void)URLSession:(NSURLSession *)session
          dataTask:(NSURLSessionDataTask *)dataTask
    didReceiveData:(NSData *)data {
    [_outputStream write:[data bytes] maxLength:data.length];
}

// 完成
- (void)URLSession:(NSURLSession *)session
              task:(NSURLSessionTask *)task
didCompleteWithError:(nullable NSError *)error {
    [_outputStream close];
}

@end

注意一： NSURLSessionDataTask下载的数据是在内存中的。需要通过NSOutputStream写入沙盒。（不要NSData直接写入沙盒，性能较差）
注意二：使用NSFileManager获取沙盒文件的size。

文件上传

文件上传的核心是表单的拼接，如下是表单的示例

--Boundary+AA1C6D73B71C103F
Content-Disposition: form-data; name="paramKey1"
 
paramValue1
--Boundary+AA1C6D73B71C103F
Content-Disposition: form-data; name="paramKey2"
 
paramValue2
--Boundary+AA1C6D73B71C103F
Content-Disposition: form-data; name="image"; filename="customName"
Content-Type: image/png
 
PNG;��^3����)or�!�.st�n��x(+9'���...

表单由四部分组成：
　　1，开始和结束边界，如–Boundary+28FBA24634750C95–
　　2，请求参数，如Content-Disposition: form-data;name=”paramKey1” paramValue1
　　3，上传文件的属性，如Content-Type: image/png
　　4，上传文件的数据，如PNG;��^3��)or�!�.st�n��x(+9’��
　　
二进制形式的表单就是请求体。

使用NSMutableURLRequest.HTTPBody属性设置请求体，如下代码所示：

// 文件上传
- (void)uploadImage {
    
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:UploadImageURL]];
    // 表单拼接
    NSString *bounary = @"******"; // 分界线
    // 一 配置请求头
    [request setValue:[NSString stringWithFormat:@"multipart/form-data;charset=utf-8;boundary=%@", bounary]  forHTTPHeaderField:@"Content-Type"];
    // 二 配置请求体
    NSMutableData *bodyData = [NSMutableData data];
    // 1，开始边界
    NSString *beginBoundary = [NSString stringWithFormat:@"--%@\r\n", bounary];
    [bodyData appendData:[beginBoundary dataUsingEncoding:NSUTF8StringEncoding]];
    // 2，属性 name和服务的name要匹配,相当于服务获取图片的key
    //  filename 服务器图片文件命名
    NSString *serverFileKey = @"image";
    NSString *serverFileName = @"101.png";
    NSString *serverContentTypes = @"image/png";
    
    NSMutableString *string = [NSMutableString string];
    [string appendFormat:@"Content-Disposition:form-data; name=\"%@\"; filename=\"%@\" \r\n", serverFileKey, serverFileName];
    [string appendFormat:@"Content-Type: %@\r\n", serverContentTypes];
    [string appendFormat:@"\r\n"];
    [bodyData appendData:[string dataUsingEncoding:NSUTF8StringEncoding]];
    
    // 3，上传文件数据
    UIImage *image = [UIImage imageNamed:@"demo.png"];
    NSData *imageData = UIImagePNGRepresentation(image);
    [bodyData appendData:imageData];
    
    // 4，结束边界
    NSString *endBoundary = [NSString stringWithFormat:@"\r\n--%@", bounary];
    [bodyData appendData:[endBoundary dataUsingEncoding:NSUTF8StringEncoding]];
    
    request.HTTPBody = bodyData;
    request.HTTPMethod = @"POST";
    
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:nil];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request];
    [task resume];
}

// 进度
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend{
    
    NSLog(@"didSendBodyData:: %lld--%lld--%lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}

// 完成
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{
    NSLog(@"上传完成");
}

表单注意点：一，每个部分都是以\n为结束点。二，属性中的name和服务的name要匹配。

使用NSMutableURLRequest.HTTPBodyStream属性设置请求体，如下代码所示：

@interface InputStreamUploadController ()<NSURLSessionDelegate>

@end

#define UploadImageURL @"http://www.8pmedu.com/themes/jianmo/img/upload.php"

@implementation InputStreamUploadController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = UIColorRandomColor;
    
    [self inputStream];
}

- (void)inputStream {
    
    NSString *bodyStr = @"versions_id=1&system_type=1";
    NSInputStream *inputsteam = [[NSInputStream alloc] initWithData:[bodyStr dataUsingEncoding:NSUTF8StringEncoding]];
    [inputsteam open];
    
    uint8_t buffer[256];
    memset(buffer, 0, 256);// 清空该段内存
    [inputsteam read:buffer maxLength:9];
    NSLog(@"++++%s", buffer);
    
    memset(buffer, 0, 256);// 清空该段内存
    [inputsteam read:buffer maxLength:3];
    NSLog(@"----%s", buffer);
    [inputsteam close];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self uploadImage];
}

- (void)uploadImage {
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:UploadImageURL]];
    // 配置请求头和请求体
    NSString *bounary = @"******"; // 分界线
    // 一 配置请求头
    [request setValue:[NSString stringWithFormat:@"multipart/form-data;charset=utf-8;boundary=%@", bounary]  forHTTPHeaderField:@"Content-Type"];
    // 二 配置请求体
    NSMutableData *bodyData = [NSMutableData data];
    // 1 开始边界
    NSString *beginBoundary = [NSString stringWithFormat:@"--%@\r\n", bounary];
    [bodyData appendData:[beginBoundary dataUsingEncoding:NSUTF8StringEncoding]];
    // 2 属性 name和服务的name要匹配，相当于获取服务图片的key
    //  filename 服务器图片文件命名
    NSString *serverFileKey = @"image";
    NSString *serverFileName = @"101.png";
    NSString *serverContentTypes = @"image/png";
    
    NSMutableString *string = [NSMutableString string];
    [string appendFormat:@"Content-Disposition:form-data; name=\"%@\"; filename=\"%@\" \r\n", serverFileKey, serverFileName];
    [string appendFormat:@"Content-Type: %@\r\n", serverContentTypes];
    [string appendFormat:@"\r\n"];
    [bodyData appendData:[string dataUsingEncoding:NSUTF8StringEncoding]];
    
    // 3 文件数据
    UIImage *image = [UIImage imageNamed:@"1"];
    NSData *imageData = UIImagePNGRepresentation(image);
    [bodyData appendData:imageData];
    
    // 4 结束边界
    NSString *endBoundary = [NSString stringWithFormat:@"\r\n--%@", bounary];
    [bodyData appendData:[endBoundary dataUsingEncoding:NSUTF8StringEncoding]];
    
     NSInputStream *inputsteam = [[NSInputStream alloc] initWithData:bodyData];
     [request setHTTPBodyStream:inputsteam]; // 请求的时候，系统底层会对NSInputStream执行read操作
     
     NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:nil];
     
     NSURLSessionTask *task = [session dataTaskWithRequest:request];
     [task resume];
}

#pragma mark - NSURLSessionDelegate
// 进度
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend{
    NSLog(@"didSendBodyData:: %lld--%lld--%lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}

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

@end

** 文件上传的NSURLRequest实例，需要配置如下属性：**
1，URL
2，HTTPMethod
3，setValue:forHTTPHeaderField:
4，HTTPBody/HTTPBodyStream

原文作者：朱献国

原文链接：http://onzxgway.github.io/2017/06/20/network-1/

发表日期：June 20th 2017, 6:56:59 pm

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CATALOG

1. 普通下载
2. 断点下载
3. 文件上传



缺失模块。
1、请确保node版本大于6.2
2、在博客根目录（注意不是archer根目录）执行以下命令：
npm i hexo-generator-json-content --save
3、在根目录_config.yml里添加配置：

jsonContent:
  meta: false
  pages: false
  posts:
    title: true
    date: true
    path: true
    text: false
    raw: false
    content: false
    slug: false
    updated: false
    comments: false
    link: false
    permalink: false
    excerpt: false
    categories: true
    tags: true