Object Storage Service:Simple download using OSS SDK for iOS

Prerequisites

Before you begin, ensure that you have:

• An OSSClient instance initialized with a custom domain name or Security Token Service (STS). See Initialization (iOS SDK)

• The required permissions granted to your RAM user or RAM role (see Permissions below)

Permissions

By default, an Alibaba Cloud account has full permissions. RAM users and RAM roles have no permissions by default. The account owner or administrator must grant access through RAM Policy or Bucket policies.

Download an object

OSSGetObjectRequest *request = [OSSGetObjectRequest new];

// Required: bucket name and full object key (must not include the bucket name)
request.bucketName = @"examplebucket";
request.objectKey  = @"exampledir/exampleobject.txt";

// Optional: track download progress
request.downloadProgress = ^(int64_t bytesWritten,
                              int64_t totalBytesWritten,
                              int64_t totalBytesExpectedToWrite) {
    // bytesWritten                  — bytes downloaded in this chunk
    // totalBytesWritten             — total bytes downloaded so far
    // totalBytesExpectedToWrite     — total size of the object
    NSLog(@"%lld, %lld, %lld", bytesWritten, totalBytesWritten, totalBytesExpectedToWrite);
};

OSSTask *getTask = [client getObject:request];

[getTask continueWithBlock:^id(OSSTask *task) {
    if (!task.error) {
        OSSGetObjectResult *getResult = task.result;
        NSLog(@"download object success! data: %@", getResult.downloadedData);
    } else {
        NSLog(@"download object failed, error: %@", task.error);
    }
    return nil;
}];

OSSGetObjectRequest *request = [OSSGetObjectRequest new];
request.bucketName      = @"examplebucket";
request.objectKey       = @"exampledir/exampleobject.txt";
request.downloadToFileURL = [NSURL fileURLWithPath:@"<local-file-path>"];

OSSTask *getTask = [client getObject:request];

[getTask continueWithBlock:^id(OSSTask *task) {
    if (!task.error) {
        NSLog(@"download object success!");
    } else {
        NSLog(@"download object failed, error: %@", task.error);
    }
    return nil;
}];

// Download bytes 0-99 (inclusive)
request.range = [[OSSRange alloc] initWithStart:0 withEnd:99];

Pause and cancel a download

[client getObject:request] returns an OSSTask. Use it to wait for completion or cancel the request.

// Block the current thread until the download completes
[getTask waitUntilFinished];

// Cancel the download
[request cancel];

What's next

• For details on the underlying API, see GetObject.

• To set up your OSSClient, see Initialization (iOS SDK).