ios断点续传:NSURLSession和NSURLSessionDataTask实现
2015-10-21 14:34
507 查看
苹果提供的NSURLSessionDownloadTask虽然能实现断点续传，但是有些情况是无法处理的，比如程序强制退出或没有调用
cancelByProducingResumeData取消方法，这时就无法断点续传了。
使用NSURLSession和NSURLSessionDataTask实现断点续传的过程是：
1、配置NSMutableURLRequest对象的Range请求头字段信息
2、创建使用代理的NSURLSession对象
3、使用NSURLSession对象和NSMutableURLRequest对象创建NSURLSessionDataTask对象，启动任务。
4、在NSURLSessionDataDelegate的didReceiveData方法中追加获取下载数据到目标文件。
下面是具体实现，封装了一个续传管理器。可以直接拷贝到你的工程里，也可以参考我提供的DEMO：http://pan.baidu.com/s/1c0BHToW
//
// MQLResumeManager.h
//
// Created by MQL on 15/10/21.
// Copyright © 2015年. All rights reserved.
//
#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*)url
targetPath:(NSString*)targetPath
success:(void (^)())success
failure:(void (^)(NSError *error))failure
progress:(void (^)(longlong totalReceivedContentLength,longlong
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
//
// MQLResumeManager.m
//
// Created by MQL on 15/10/21.
// Copyright © 2015年. All rights reserved.
//
#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 longlong totalContentLength; //文件总大小
@property longlong 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 (^)())success
failure:(void (^)(NSError *error))failure;
/**
* 设置进度回调block
*
* @param progress
*/
-(void)setProgressBlockWithProgress:(void (^)(longlong totalReceivedContentLength,longlong
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 (^)())success
failure:(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 (^)(longlong totalReceivedContentLength,longlong
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 = [NSFileManagernew];//
not thread safe
if ([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*)url
targetPath:(NSString*)targetPath
success:(void (^)())success
failure:(void (^)(NSError *error))failure
progress:(void (^)(longlong totalReceivedContentLength,longlong
totalContentLength))progress{
MQLResumeManager *manager = [[MQLResumeManageralloc]init];
manager.url = url;
manager.targetPath = targetPath;
[manager setCompletionBlockWithSuccess:successfailure: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 = [[NSMutableURLRequestalloc]initWithURL:self.url];
longlong downloadedBytes =self.totalReceivedContentLength
= [selffileSizeForPath:self.targetPath];
if (downloadedBytes >
0) {
NSString *requestRange = [NSStringstringWithFormat:@"bytes=%llu-", downloadedBytes];
[request setValue:requestRange
forHTTPHeaderField:@"Range"];
}else{
int fileDescriptor =
open([self.targetPathUTF8String],O_CREAT |O_EXCL |O_RDWR,0666);
if (fileDescriptor >
0) {
close(fileDescriptor);
}
}
NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfigurationdefaultSessionConfiguration];
NSOperationQueue *queue = [[NSOperationQueuealloc]init];
self.session = [NSURLSessionsessionWithConfiguration:sessionConfigurationdelegate:selfdelegateQueue:queue];
NSURLSessionDataTask *dataTask = [self.sessiondataTaskWithRequest:request];
[dataTask resume];
}
/**
* 取消断点续传下载请求
*/
-(void)cancel{
if (self.session) {
[self.sessioninvalidateAndCancel];
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:(nullableNSError *)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 *)dataTask
didReceiveData:(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.allHeaderFieldsvalueForKey:@"Content-Range"];
if ([contentRange
hasPrefix:@"bytes"]) {
NSArray *bytes = [contentRangecomponentsSeparatedByCharactersInSet:[NSCharacterSetcharacterSetWithCharactersInString:@"
-/"]];
if ([bytes
count] == 4) {
self.totalContentLength = [[bytesobjectAtIndex:3]longLongValue];
}
}
}else if (response.statusCode ==416){
NSString *contentRange = [response.allHeaderFieldsvalueForKey:@"Content-Range"];
if ([contentRange
hasPrefix:@"bytes"]) {
NSArray *bytes = [contentRangecomponentsSeparatedByCharactersInSet:[NSCharacterSetcharacterSetWithCharactersInString:@"
-/"]];
if ([bytes
count] == 3) {
self.totalContentLength = [[bytesobjectAtIndex:2]longLongValue];
if (self.totalReceivedContentLength ==self.totalContentLength)
{
//说明已下完
//更新进度
self.progressBlock();
}else{
//416 Requested Range Not Satisfiable
self.error = [[NSErroralloc]initWithDomain:[self.urlabsoluteString]code:416userInfo:response.allHeaderFields];
}
}
}
return;
}else{
//其他情况还没发现
return;
}
//向文件追加数据
NSFileHandle *fileHandle = [NSFileHandlefileHandleForUpdatingAtPath: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
经验证，如果app后台能运行，datatask是支持后台传输的。
让您的app成为后台运行app非常简单：
#import "AppDelegate.h"
static UIBackgroundTaskIdentifier bgTask;
@interface AppDelegate ()
@end
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
return YES;
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
[self getBackgroundTask];
}
- (void)applicationWillEnterForeground:(UIApplication *)application {
[self endBackgroundTask];
}
/**
* 获取后台任务
*/
-(void)getBackgroundTask{
NSLog(@"getBackgroundTask");
UIBackgroundTaskIdentifier tempTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
}];
if (bgTask != UIBackgroundTaskInvalid) {
[self endBackgroundTask];
}
bgTask = tempTask;
[self performSelector:@selector(getBackgroundTask) withObject:nil afterDelay:120];
}
/**
* 结束后台任务
*/
-(void)endBackgroundTask{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
@end
cancelByProducingResumeData取消方法，这时就无法断点续传了。
使用NSURLSession和NSURLSessionDataTask实现断点续传的过程是：
1、配置NSMutableURLRequest对象的Range请求头字段信息
2、创建使用代理的NSURLSession对象
3、使用NSURLSession对象和NSMutableURLRequest对象创建NSURLSessionDataTask对象，启动任务。
4、在NSURLSessionDataDelegate的didReceiveData方法中追加获取下载数据到目标文件。
下面是具体实现，封装了一个续传管理器。可以直接拷贝到你的工程里，也可以参考我提供的DEMO：http://pan.baidu.com/s/1c0BHToW
//
// MQLResumeManager.h
//
// Created by MQL on 15/10/21.
// Copyright © 2015年. All rights reserved.
//
#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*)url
targetPath:(NSString*)targetPath
success:(void (^)())success
failure:(void (^)(NSError *error))failure
progress:(void (^)(longlong totalReceivedContentLength,longlong
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
//
// MQLResumeManager.m
//
// Created by MQL on 15/10/21.
// Copyright © 2015年. All rights reserved.
//
#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 longlong totalContentLength; //文件总大小
@property longlong 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 (^)())success
failure:(void (^)(NSError *error))failure;
/**
* 设置进度回调block
*
* @param progress
*/
-(void)setProgressBlockWithProgress:(void (^)(longlong totalReceivedContentLength,longlong
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 (^)())success
failure:(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 (^)(longlong totalReceivedContentLength,longlong
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 = [NSFileManagernew];//
not thread safe
if ([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*)url
targetPath:(NSString*)targetPath
success:(void (^)())success
failure:(void (^)(NSError *error))failure
progress:(void (^)(longlong totalReceivedContentLength,longlong
totalContentLength))progress{
MQLResumeManager *manager = [[MQLResumeManageralloc]init];
manager.url = url;
manager.targetPath = targetPath;
[manager setCompletionBlockWithSuccess:successfailure: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 = [[NSMutableURLRequestalloc]initWithURL:self.url];
longlong downloadedBytes =self.totalReceivedContentLength
= [selffileSizeForPath:self.targetPath];
if (downloadedBytes >
0) {
NSString *requestRange = [NSStringstringWithFormat:@"bytes=%llu-", downloadedBytes];
[request setValue:requestRange
forHTTPHeaderField:@"Range"];
}else{
int fileDescriptor =
open([self.targetPathUTF8String],O_CREAT |O_EXCL |O_RDWR,0666);
if (fileDescriptor >
0) {
close(fileDescriptor);
}
}
NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfigurationdefaultSessionConfiguration];
NSOperationQueue *queue = [[NSOperationQueuealloc]init];
self.session = [NSURLSessionsessionWithConfiguration:sessionConfigurationdelegate:selfdelegateQueue:queue];
NSURLSessionDataTask *dataTask = [self.sessiondataTaskWithRequest:request];
[dataTask resume];
}
/**
* 取消断点续传下载请求
*/
-(void)cancel{
if (self.session) {
[self.sessioninvalidateAndCancel];
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:(nullableNSError *)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 *)dataTask
didReceiveData:(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.allHeaderFieldsvalueForKey:@"Content-Range"];
if ([contentRange
hasPrefix:@"bytes"]) {
NSArray *bytes = [contentRangecomponentsSeparatedByCharactersInSet:[NSCharacterSetcharacterSetWithCharactersInString:@"
-/"]];
if ([bytes
count] == 4) {
self.totalContentLength = [[bytesobjectAtIndex:3]longLongValue];
}
}
}else if (response.statusCode ==416){
NSString *contentRange = [response.allHeaderFieldsvalueForKey:@"Content-Range"];
if ([contentRange
hasPrefix:@"bytes"]) {
NSArray *bytes = [contentRangecomponentsSeparatedByCharactersInSet:[NSCharacterSetcharacterSetWithCharactersInString:@"
-/"]];
if ([bytes
count] == 3) {
self.totalContentLength = [[bytesobjectAtIndex:2]longLongValue];
if (self.totalReceivedContentLength ==self.totalContentLength)
{
//说明已下完
//更新进度
self.progressBlock();
}else{
//416 Requested Range Not Satisfiable
self.error = [[NSErroralloc]initWithDomain:[self.urlabsoluteString]code:416userInfo:response.allHeaderFields];
}
}
}
return;
}else{
//其他情况还没发现
return;
}
//向文件追加数据
NSFileHandle *fileHandle = [NSFileHandlefileHandleForUpdatingAtPath: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
经验证，如果app后台能运行，datatask是支持后台传输的。
让您的app成为后台运行app非常简单：
#import "AppDelegate.h"
static UIBackgroundTaskIdentifier bgTask;
@interface AppDelegate ()
@end
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
return YES;
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
[self getBackgroundTask];
}
- (void)applicationWillEnterForeground:(UIApplication *)application {
[self endBackgroundTask];
}
/**
* 获取后台任务
*/
-(void)getBackgroundTask{
NSLog(@"getBackgroundTask");
UIBackgroundTaskIdentifier tempTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
}];
if (bgTask != UIBackgroundTaskInvalid) {
[self endBackgroundTask];
}
bgTask = tempTask;
[self performSelector:@selector(getBackgroundTask) withObject:nil afterDelay:120];
}
/**
* 结束后台任务
*/
-(void)endBackgroundTask{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
@end
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