Object Storage Service:Streaming download (iOS SDK)

Usage notes

• Before you use the sample code in this topic, you must create an OSSClient instance. You can create an instance using a custom domain name or Security Token Service (STS). For more information, see Initialization (iOS SDK).

  Note

  The region of the bucket depends on the region of the endpoint that you specify during initialization.

• The Object Storage Service (OSS) SDK for iOS does not provide an API operation for stream-based downloads. Instead, it provides a segmented callback feature similar to the NSURLSession library's didReceiveData function. If you set a segmented callback, the download result does not contain the actual data.

Permissions

By default, an Alibaba Cloud account has full permissions. RAM users or RAM roles under an Alibaba Cloud account do not have any permissions by default. The Alibaba Cloud account or account administrator must grant operation permissions through RAM Policy or Bucket policies.

Sample code

The following code shows how to perform a streaming download:

OSSGetObjectRequest * request = [OSSGetObjectRequest new];
// Specify the bucket name. For example, examplebucket.
request.bucketName = @"examplebucket";
// Specify the full path of the object. Do not include the bucket name. For example, exampledir/exampleobject.txt.
request.objectKey = @"exampledir/exampleobject.txt";
// Set the segmented callback function.
request.onRecieveData = ^(NSData * data) {
    NSLog(@"Recieve data, length: %ld", [data length]);
};
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;
}];
// [getTask waitUntilFinished];
// [request cancel];

Related documents

• For more information about the API operation for streaming download, see GetObject.

• For more information about initializing an OSSClient instance, see Initialization (iOS SDK).