NSURLSession实现续点下载

2024-04-17 08:58
文章标签 实现 下载 nsurlsession 续点

本文主要是介绍NSURLSession实现续点下载，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！ 

#import <Foundation/Foundation.h>
@interface MQLResumeManager : NSObject
/***  创建断点续传管理对象，启动下载请求**  @param url          文件资源地址*  @param targetPath   文件存放路径*  @param success      文件下载成功的回调块*  @param failure      文件下载失败的回调块*  @param progress     文件下载进度的回调块**  @return 断点续传管理对象**/
+(MQLResumeManager*)resumeManagerWithURL:(NSURL*)urltargetPath:(NSString*)targetPathsuccess:(void (^)())successfailure:(void (^)(NSError *error))failureprogress:(void (^)(long long totalReceivedContentLength, long long totalContentLength))progress;
/***  启动断点续传下载请求*/
-(void)start;/***  取消断点续传下载请求*/
-(void)cancel;
@end
#import "MQLResumeManager.h"typedef void (^completionBlock)();
typedef void (^progressBlock)();@interface MQLResumeManager ()<NSURLSessionDelegate, NSURLSessionTaskDelegate>@property (nonatomic, strong) NSURLSession *session;    //注意一个session只能有一个请求任务
@property(nonatomic, readwrite, retain) NSError *error; //请求出错
@property(nonatomic, readwrite, copy) completionBlock completionBlock;
@property(nonatomic, readwrite, copy) progressBlock progressBlock;@property (nonatomic, strong) NSURL *url;           //文件资源地址
@property (nonatomic, strong) NSString *targetPath; //文件存放路径
@property long long totalContentLength;             //文件总大小
@property long long totalReceivedContentLength;     //已下载大小/***  设置成功、失败回调block**  @param success 成功回调block*  @param failure 失败回调block*/
- (void)setCompletionBlockWithSuccess:(void (^)())successfailure:(void (^)(NSError *error))failure;/***  设置进度回调block**  @param progress*/
-(void)setProgressBlockWithProgress:(void (^)(long long totalReceivedContentLength, long long totalContentLength))progress;/***  获取文件大小*  @param path 文件路径*  @return 文件大小**/
- (long long)fileSizeForPath:(NSString *)path;@end@implementation MQLResumeManager/***  设置成功、失败回调block**  @param success 成功回调block*  @param failure 失败回调block*/
- (void)setCompletionBlockWithSuccess:(void (^)())successfailure:(void (^)(NSError *error))failure{__weak typeof(self) weakSelf = self;self.completionBlock = ^ {dispatch_async(dispatch_get_main_queue(), ^{if (weakSelf.error) {if (failure) {failure(weakSelf.error);}} else {if (success) {success();}}});};
}/***  设置进度回调block**  @param progress*/
-(void)setProgressBlockWithProgress:(void (^)(long long totalReceivedContentLength, long long totalContentLength))progress{__weak typeof(self) weakSelf = self;self.progressBlock = ^{dispatch_async(dispatch_get_main_queue(), ^{progress(weakSelf.totalReceivedContentLength, weakSelf.totalContentLength);});};
}/***  获取文件大小*  @param path 文件路径*  @return 文件大小**/
- (long long)fileSizeForPath:(NSString *)path {long long fileSize = 0;NSFileManager *fileManager = [NSFileManager new]; // not thread safeif ([fileManager fileExistsAtPath:path]) {NSError *error = nil;NSDictionary *fileDict = [fileManager attributesOfItemAtPath:path error:&error];if (!error && fileDict) {fileSize = [fileDict fileSize];}}return fileSize;
}/***  创建断点续传管理对象，启动下载请求*  @param url          文件资源地址*  @param targetPath   文件存放路径*  @param success      文件下载成功的回调块*  @param failure      文件下载失败的回调块*  @param progress     文件下载进度的回调块**  @return 断点续传管理对象**/
+(MQLResumeManager*)resumeManagerWithURL:(NSURL*)urltargetPath:(NSString*)targetPathsuccess:(void (^)())successfailure:(void (^)(NSError *error))failureprogress:(void (^)(long long totalReceivedContentLength, long long totalContentLength))progress{MQLResumeManager *manager = [[MQLResumeManager alloc]init];manager.url = url;manager.targetPath = targetPath;[manager setCompletionBlockWithSuccess:success failure:failure];[manager setProgressBlockWithProgress:progress];manager.totalContentLength = 0;manager.totalReceivedContentLength = 0;return manager;
}/***  启动断点续传下载请求*/
-(void)start{NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:self.url];long long downloadedBytes = self.totalReceivedContentLength = [self fileSizeForPath:self.targetPath];if (downloadedBytes > 0) {NSString *requestRange = [NSString stringWithFormat:@"bytes=%llu-", downloadedBytes];[request setValue:requestRange forHTTPHeaderField:@"Range"];}else{int fileDescriptor = open([self.targetPath UTF8String], O_CREAT | O_EXCL | O_RDWR, 0666);if (fileDescriptor > 0) {close(fileDescriptor);}}NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];NSOperationQueue *queue = [[NSOperationQueue alloc]init];self.session = [NSURLSession sessionWithConfiguration:sessionConfiguration delegate:self delegateQueue:queue];NSURLSessionDataTask *dataTask = [self.session dataTaskWithRequest:request];[dataTask resume];
}/***  取消断点续传下载请求*/
-(void)cancel{if (self.session) {[self.session invalidateAndCancel];self.session = nil;}
}#pragma mark -- NSURLSessionDelegate
/* The last message a session delegate receives.  A session will only become* invalid because of a systemic error or when it has been* explicitly invalidated, in which case the error parameter will be nil.*/
- (void)URLSession:(NSURLSession *)session didBecomeInvalidWithError:(nullable NSError *)error{NSLog(@"didBecomeInvalidWithError");
}#pragma mark -- NSURLSessionTaskDelegate
/* Sent as the last message related to a specific task.  Error may be* nil, which implies that no error occurred and this task is complete.*/
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task
didCompleteWithError:(nullable NSError *)error{NSLog(@"didCompleteWithError");if (error == nil && self.error == nil) {self.completionBlock();}else if (error != nil){if (error.code != -999) {self.error = error;self.completionBlock();}}else if (self.error != nil){self.completionBlock();}}#pragma mark -- NSURLSessionDataDelegate
/* Sent when data is available for the delegate to consume.  It is* assumed that the delegate will retain and not copy the data.  As* the data may be discontiguous, you should use* [NSData enumerateByteRangesUsingBlock:] to access it.*/
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTaskdidReceiveData:(NSData *)data{//根据status code的不同，做相应的处理NSHTTPURLResponse *response = (NSHTTPURLResponse*)dataTask.response;if (response.statusCode == 200) {self.totalContentLength = dataTask.countOfBytesExpectedToReceive;}else if (response.statusCode == 206){NSString *contentRange = [response.allHeaderFields valueForKey:@"Content-Range"];if ([contentRange hasPrefix:@"bytes"]) {NSArray *bytes = [contentRange componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" -/"]];if ([bytes count] == 4) {self.totalContentLength = [[bytes objectAtIndex:3] longLongValue];}}}else if (response.statusCode == 416){NSString *contentRange = [response.allHeaderFields valueForKey:@"Content-Range"];if ([contentRange hasPrefix:@"bytes"]) {NSArray *bytes = [contentRange componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" -/"]];if ([bytes count] == 3) {self.totalContentLength = [[bytes objectAtIndex:2] longLongValue];if (self.totalReceivedContentLength == self.totalContentLength) {//说明已下完//更新进度self.progressBlock();}else{//416 Requested Range Not Satisfiableself.error = [[NSError alloc]initWithDomain:[self.url absoluteString] code:416 userInfo:response.allHeaderFields];}}}return;}else{//其他情况还没发现return;}//向文件追加数据NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:self.targetPath];[fileHandle seekToEndOfFile]; //将节点跳到文件的末尾[fileHandle writeData:data];//追加写入数据[fileHandle closeFile];//更新进度self.totalReceivedContentLength += data.length;self.progressBlock();
}
@end

在控制器里面实现续点下载

#import "ViewController.h"
#import "MQLResumeManager.h"@interface ViewController ()@property (nonatomic, strong) MQLResumeManager *manager;@property (nonatomic, weak) IBOutlet UIImageView *imageWithBlock;
@property (nonatomic, strong) NSString *targetPath;@property (nonatomic, weak) IBOutlet UIProgressView *progressView;
@property (nonatomic, weak) IBOutlet UILabel *lab;
@property (nonatomic, weak) IBOutlet UIButton *deleteBtn;/***  简单请求*  @param sender*/
-(IBAction)simpleRequest:(id)sender;/***  取消请求*  @param sender*/
-(IBAction)cancelRequest:(id)sender;/***  删除文件*  @param sender*/
-(IBAction)deleteImage:(id)sender;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];
}/***  简单请求*  @param sender*/
-(IBAction)simpleRequest:(id)sender{//1.准备if (self.manager) {[self cancelRequest:nil];}NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *documentsDirectory=[paths objectAtIndex:0];//Documents目录self.targetPath = [documentsDirectory stringByAppendingPathComponent:@"myPic"];//    NSURL *url = [NSURL URLWithString:@"http://p1.pichost.me/i/40/1639665.png"];NSURL *url = [NSURL URLWithString:@"http://p1.pichost.me/i/40/1639665.png"];self.manager = [MQLResumeManager resumeManagerWithURL:url targetPath:self.targetPath success:^{NSLog(@"success");self.imageWithBlock.image = [UIImage imageWithContentsOfFile:self.targetPath];self.deleteBtn.hidden = NO;} failure:^(NSError *error) {NSLog(@"failure");} progress:^(long long totalReceivedContentLength, long long totalContentLength) {float percent = 1.0 * totalReceivedContentLength / totalContentLength;NSString *strPersent = [[NSString alloc]initWithFormat:@"%.f", percent *100];self.progressView.progress = percent;self.lab.text = [NSString stringWithFormat:@"已下载%@%%", strPersent];}];//2.启动[self.manager start];}/***  取消请求*  @param sender*/
-(IBAction)cancelRequest:(id)sender{[self.manager cancel];self.manager = nil;
}/***  删除文件**  @param sender*/
-(IBAction)deleteImage:(id)sender{NSFileManager *manager = [NSFileManager defaultManager];NSError *error = nil;[manager removeItemAtPath:self.targetPath error:&error];if (error == nil) {self.imageWithBlock.image = [UIImage imageWithContentsOfFile:self.targetPath];self.progressView.progress = 0;self.lab.text = nil;self.deleteBtn.hidden = YES;}
}
@end

这样就实现续点下载的操作

这篇关于NSURLSession实现续点下载的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！


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