从亚马逊S3下载所有图片

Question

到目前为止，我已经非常幸运地学习并实现了将图片上传到亚马逊的S3服务。我要把照片上传到服务器上。都具有不同的名称，因此不会覆盖另一个名称。

我可以下载一个镜像，但只能使用一个特定的名称(即“image.png”)。我想下载所有的镜像。然后我会将它们放在一个tableView中。我只是在文档中找不到这个问题的答案。这是我的代码，可以下载一个镜像。

-(void)download{

    //Creating S3 transfer manager client
    AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];


    //Dowloading actual object
    //Create the NSURL for thte download location.

    NSString *downloadingFilePath = [NSTemporaryDirectory()stringByAppendingPathComponent:@"downloaded-image.png"];
    NSURL *downloadingFileURL = [NSURL fileURLWithPath:downloadingFilePath];

    //Construct download request
    AWSS3TransferManagerDownloadRequest *downloadRequest = [AWSS3TransferManagerDownloadRequest new];

    downloadRequest.bucket = @"MyBucketName";
    downloadRequest.key = @"image.png";  //<----- I can only download an image by this name?
    downloadRequest.downloadingFileURL = downloadingFileURL;


    //Download the file
    [[transferManager download:downloadRequest]continueWithExecutor:[BFExecutor mainThreadExecutor] withBlock:^id(BFTask *task) {
        if (task.error) {
            if ([task.error.domain isEqualToString:AWSS3TransferManagerErrorDomain]) {
                switch (task.error.code) {
                    case AWSS3TransferManagerErrorCancelled:
                    case AWSS3TransferManagerErrorPaused:

                        break;

                    default:
                        NSLog(@"Error: %@", task.error);
                        break;
                }
            }else{
                //Unknown Error
                NSLog(@"Error: %@", task.error);
            }
        }
        if (task.result) {
            AWSS3TransferManagerDownloadOutput *downloadOutput = task.result;
            //File downloade successfully
            NSLog(@"Download Output: %@", downloadOutput);
        }
        self.selectedImageView.image = [UIImage imageWithContentsOfFile:downloadingFilePath];
        return nil;
    }];

}

Answer 1

AWSS3有一个名为- listObjects:的方法，它返回AWSS3ListObjectsOutput的一个实例。AWSS3ListObjectsOutput的contents属性是一个AWSS3Object数组。您可以遍历数组并在AWSS3Object的每个key上调用- download:，以便下载存储桶中的所有对象。

Answer 2

如果您想采用惰性方法，AWS Command-Line Interface (CLI)可以在一个命令中复制多个文件，甚至是递归子目录。

还有aws s3 sync命令，它只能复制新的或修改过的文件，包括子目录。

因此，您可能希望调用CLI来下载图片，然后使用您自己的代码处理它们。

Answer 3

您可以使用AWSS3ListObjectsRequest从Bucket下载所有图片。下面是代码。

AWSS3ListObjectsRequest *listObjectsRequest = AWSS3ListObjectsRequest新建；listObjectsRequest.bucket = @"YourBucketName"；

[[s3 listObjects:listObjectsRequest] continueWithBlock:^id(AWSTask *task)
 {
    if (task.error)
    {
        [MBProgressHUD hideAllHUDsForView:self.view animated:YES];
        NSLog(@"listObjects failed: [%@]", task.error);
    }
    else
    {
        AWSS3ListObjectsOutput *listObjectsOutput = task.result;

        for (AWSS3Object *s3Object in listObjectsOutput.contents)
        {
            downloadingFilePath = [[NSTemporaryDirectory() stringByAppendingPathComponent:@"download"] stringByAppendingPathComponent:s3Object.key];

            NSURL *downloadingFileURL = [NSURL fileURLWithPath:downloadingFilePath];

            AWSS3TransferManagerDownloadRequest *downloadRequest = [AWSS3TransferManagerDownloadRequest new];
            downloadRequest.bucket = @"YourBucketName";
            downloadRequest.key = s3Object.key;
            downloadRequest.downloadingFileURL = downloadingFileURL;

            AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];
            [[transferManager download:downloadRequest] continueWithBlock:^id(AWSTask *task)
             {
                 if ([task.error.domain isEqualToString:AWSS3TransferManagerErrorDomain]
                     && task.error.code == AWSS3TransferManagerErrorPaused)
                 {
                     NSLog(@"Download paused.");
                 }
                 else if (task.error)
                 {
                     NSLog(@"Upload failed: [%@]", task.error);
                 }
                 else
                 {
                     dispatch_async(dispatch_get_main_queue(), ^
                                    {
                                        //_imgNew.image = [ UIImage imageNamed:[NSString stringWithFormat:@"%@",downloadRequest.downloadingFileURL]];
                                    });
                 }
                 return nil;
             }];
        }

        dispatch_async(dispatch_get_main_queue(), ^{
            [self setUpScrollViews];
            NSLog(@"Set images called");
            [MBProgressHUD hideAllHUDsForView:self.view animated:YES];
        });
    }
    return nil;
}];