Question

我是使用Amazon S3上传和下载数据的iOS开发人员。我成功上传了许多图片文件，但是当我尝试下载所有文件时，我无法在S3GetObjectRequest的目标路径上保存数据或文件。我通过S3TransferManager请求对象。

以下是我的代码

- (void)listObjects:(id)sender {

    self.collection = [[NSMutableArray alloc] init];

    s3Client = [[AmazonS3Client alloc] initWithAccessKey:ACCESS_KEY_ID withSecretKey:SECRET_KEY];

    @try {

        S3ListObjectsRequest *req = [[S3ListObjectsRequest alloc] initWithName:AMAZON_BUCKET_NAME];
        req.prefix = @"arvinds/8/";
        //req.prefix = [NSString stringWithFormat:@"%@", self.appUser.userEmail];
        S3ListObjectsResponse *resp = [s3Client listObjects:req];

        NSMutableArray* objectSummaries = resp.listObjectsResult.objectSummaries;

        for (int x = 0; x < [objectSummaries count]; x++) {
            NSLog(@"objectSummaries: %@",[objectSummaries objectAtIndex:x]);

            S3ObjectSummary *s3Object = [objectSummaries objectAtIndex:x];

            NSString *downloadingFilePath = [[NSTemporaryDirectory() stringByAppendingPathComponent:@"download"] stringByAppendingPathComponent:s3Object.key];


            NSURL *downloadingFileURL = [NSURL fileURLWithPath:downloadingFilePath];
            NSLog(@"downloadingFilePath--- %@",downloadingFilePath);

            if ([[NSFileManager defaultManager] fileExistsAtPath:downloadingFilePath]) {
                [self.collection addObject:downloadingFileURL];
            } else {

                [self.collection addObject:downloadingFileURL];

                S3GetObjectRequest *getObj = [[S3GetObjectRequest new] initWithKey:s3Object.key withBucket:AMAZON_BUCKET_NAME];
                getObj.targetFilePath = downloadingFilePath;
                getObj.delegate = self;
                [self download:getObj];// Start downloding image and write in default folder
            }
        }
        dispatch_async(dispatch_get_main_queue(), ^{
            [self.GalleryCollectionView reloadData];
            //[self downloadAllRequestObject];
        });
    }
    @catch (NSException *exception) {
        NSLog(@"Cannot list S3 %@",exception);
    }
}


// Above code is for access all the objects stored on Amazon S3 server.

// Below code is for S3TransferManager request
- (void)download:(S3GetObjectRequest *)downloadRequest {
    S3TransferManager *transferManager = [S3TransferManager new];
    transferManager.s3 = s3Client;
    transferManager.delegate = self;
    [transferManager download:downloadRequest]; 
}

执行此操作时，不会在目标路径上保存数据。

Answer 1

- download:是一个异步方法并立即返回。由于您没有保留对S3TransferManager实例的强引用，因此可以在下载完成之前发布它。您需要对transferManager保持强烈的引用。

请注意，您使用的是不推荐使用的AWS SDK版本。迁移到适用于iOS的AWS Mobile SDK版本2可能是值得的。使用最新版本的SDK，您无需担心遇到的内存保留问题。

S3TransferManager无法在ios中的S3GetObjectRequest targetedFilePath上保存文件/数据

1 个答案: