今天需要用AFNetworking實作斷點續傳的功能,但是在進行了一番研究之後,發現AFNetworking雖然支援下載下傳檔案的暫停和繼續,但是程式重新啟動後再次下載下傳無法進行續傳。網上有說可以通過AFDownloadRequestOperation這個AFNetworking的擴充庫來實作重新啟動後的續傳,但是經過本人測試,這個庫在最新的AFNetworking上會報錯,無奈之下,參考他的代碼,自己實作了一個,在這裡分享給大家。
實作的代碼如下:
- //擷取已下載下傳的檔案大小
- - (unsigned long long)fileSizeForPath:(NSString *)path {
- signed long long fileSize = 0;
- NSFileManager *fileManager = [NSFileManager new]; // default is 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;
- }
- //開始下載下傳
- - (void)startDownload {
- NSString *downloadUrl = @"http://www.xxx.com/xxx.zip";
- NSString *cacheDirectory = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
- NSString *downloadPath = [cacheDirectory stringByAppendingPathComponent:@"xxx.zip"];
- NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:downloadUrl]];
- //檢查檔案是否已經下載下傳了一部分
- unsigned long long downloadedBytes = 0;
- if ([[NSFileManager defaultManager] fileExistsAtPath:downloadPath]) {
- //擷取已下載下傳的檔案長度
- downloadedBytes = [self fileSizeForPath:downloadPath];
- if (downloadedBytes > 0) {
- NSMutableURLRequest *mutableURLRequest = [request mutableCopy];
- NSString *requestRange = [NSString stringWithFormat:@"bytes=%llu-", downloadedBytes];
- [mutableURLRequest setValue:requestRange forHTTPHeaderField:@"Range"];
- request = mutableURLRequest;
- //不使用緩存,避免斷點續傳出現問題
- [[NSURLCache sharedURLCache] removeCachedResponseForRequest:request];
- //下載下傳請求
- AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
- //下載下傳路徑
- operation.outputStream = [NSOutputStream outputStreamToFileAtPath:downloadPath append:YES];
- //下載下傳進度回調
- [operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
- //下載下傳進度
- float progress = ((float)totalBytesRead + downloadedBytes) / (totalBytesExpectedToRead + downloadedBytes);
- }];
- //成功和失敗回調
- [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
- } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
- [operation start];