Performing a Multipart Upload

Multipart upload is applicable to many scenarios, including:

• Files to be uploaded are larger than 100 MB.
• The network condition is poor. Connection to the OBS server is constantly down.
• Sizes of files to be uploaded are uncertain.

Multipart upload consists of three phases:

1. Initialize a multipart upload (initiateMultipartUpload).
2. Upload parts one by one or concurrently (uploadPart).
3. Combine parts (completeMultipartUpload) or abort the multipart upload (abortMultipartUpload).

You can call initiateMultipartUpload to initiate a multipart upload.

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
// Initiate a multipart upload.
OBSInitiateMultipartUploadRequest *request = [[OBSInitiateMultipartUploadRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname"];
    
[client initiateMultipartUpload:request completionHandler:^(OBSInitiateMultipartUploadResponse *response, NSError *error) {
    NSLog(@"%@",response);
}];

• The upload ID of the multipart upload returned by response.uploadID will be used in follow-up operations.
• In OBSInitiateMultipartUploadRequest, you can specify the MIME type, storage class, and customized metadata for the object. In addition, you can set the type of objects to be upload by setting customContentType.
• When background is set to YES, background upload is enabled.

You can call uploadPart to upload parts.

static OBSClient *client;
NSString *endPoint = @"your-endpoint";

// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
   
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
NSString *filePath = [[NSBundle mainBundle]pathForResource:@"fileName" ofType:@"Type"];
// First part
OBSUploadPartWithFileRequest* fileRequest_first =
[[OBSUploadPartWithFileRequest alloc]initWithBucketName:@"bucket-ios-test03"
                                                  objectkey:@"MultiPart"
                                                 partNumber:[NSNumber numberWithInt:1]
                                                   uploadID:@"uploadID"
                                             uploadFilePath:filePath];
// Enable background upload. When an application is switched to the background, the ongoing upload continues.
fileRequest_first.background = YES; 
    
[client uploadPart:fileRequest_first completionHandler:^(OBSUploadPartResponse *response, NSError *error) {
    NSLog(@"Part one");
}];
    
// Second part
OBSUploadPartWithFileRequest* fileRequest_sec =
[[OBSUploadPartWithFileRequest alloc]initWithBucketName:@"bucket-ios-test03"
                                                  objectkey:@"MultiPart"
                                                 partNumber:[NSNumber numberWithInt:2]
                                                   uploadID:@"uploadID"
                                             uploadFilePath:filePath];
    
[client uploadPart:fileRequest_sec completionHandler:^(OBSUploadPartResponse *response, NSError *error) {
    NSLog(@"Part two");
}];

• Except the part last uploaded, other parts must be larger than 100 KB. Part sizes will not be verified during upload because which one is last uploaded is not identified until parts are combined.
• OBS will return ETags (MD5 values) of the received parts to users.
• Part numbers range from 1 to 10000. If a part number exceeds this range, OBS will return error 400 Bad Request.
• The minimum part size supported by an OBS 3.0 bucket is 100 KB, and the minimum part size supported by an OBS 2.0 bucket is 5 MB. You are advised to perform multipart upload to OBS 3.0 buckets.

You can call completeMultipartUpload to combine parts.

static OBSClient *client;
NSString *endPoint = @"your-endpoint";

// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];

//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
// List parts.
__block NSMutableArray *partsList;
OBSListPartsRequest* listRequest = [[OBSListPartsRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:@"uploadID"];
OBSBFTask *listTask = [client listParts:listRequest completionHandler:^(OBSListPartsResponse *response, NSError *error) {
    partsList = [response.partsList mutableCopy];
        
        // Combine parts.
    OBSCompleteMultipartUploadRequest* comRequest = [[OBSCompleteMultipartUploadRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:@"uploadID"];
    comRequest.partsList = partsList;
   [client completeMultipartUpload:comRequest completionHandler:^(OBSCompleteMultipartUploadResponse *response, NSError *error) {
            NSLog(@"%@",response);
    }];
        
}];

You can call abortMultipartUpload to abort a multipart upload.

static OBSClient *client;
NSString *endPoint = @"your-endpoint";

// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
// Abort a multipart upload.
OBSAbortMultipartUploadRequest *abortRequest = [[OBSAbortMultipartUploadRequest alloc] initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:@"uploadID"];
    
[client abortMultipartUpload:abortRequest completionHandler:^(OBSAbortMultipartUploadResponse *response, NSError *error) {
    NSLog(@"%@",response);
}];

The following table describes the parameters involved in this API.

• Listing parts in simple mode

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
NSString *uploadID = @"upload id from OBSInitateMultipartUpload";
    
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
    
OBSListPartsRequest* listRequest = [[OBSListPartsRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:uploadID];
[client listParts:listRequest completionHandler:^(OBSListPartsResponse *response, NSError *error) {
    NSLog(@"%@",response);
}];

• A maximum of 1,000 parts can be listed each time. If the upload of a specified ID contains more than 1,000 parts, response.isTruncated in the response is YES, indicating not all parts were listed. In such case, you can use response.getNextPartNumberMarker to obtain the start position for next listing.
• If you want to obtain all parts involved in a specific upload ID, you can use the paging mode for listing.

• Listing all parts

The following sample code lists more than 1,000 parts:

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
NSString *uploadID = @"upload id from OBSInitateMultipartUpload";
    
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
    
__block OBSListPartsResponse *result;
    
OBSListPartsRequest* listRequest = [[OBSListPartsRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:uploadID];
    
// List all uploaded parts.
do {
    dispatch_semaphore_t sema = dispatch_semaphore_create(0);
    [client listParts:listRequest completionHandler:^(OBSListPartsResponse *response, NSError *error) {
        result = response;
        NSLog(@"%@",result);
        listRequest.partNumberMarker = result.nextPartNumberMarker;
        dispatch_semaphore_signal(sema);
    }];
    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
        
} while (result.isTruncated);

• Listing all parts in paging mode

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
NSString *uploadID = @"upload id from OBSInitateMultipartUpload";
    
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
 __block OBSListPartsResponse *result;
    
OBSListPartsRequest* listRequest = [[OBSListPartsRequest alloc]initWithBucketName:@"bucketname" objectKey:@"objectname" uploadID:uploadID];
listRequest.maxUploads = [NSNumber numberWithInt:100];
// List all uploaded parts.
do {
    dispatch_semaphore_t sema = dispatch_semaphore_create(0);
    [client listParts:listRequest completionHandler:^(OBSListPartsResponse *response, NSError *error) {
       result = response;
        NSLog(@"%@",result);
        listRequest.partNumberMarker = result.nextPartNumberMarker;
        dispatch_semaphore_signal(sema);
    }];
    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
        
} while (result.isTruncated);

• Listing multipart uploads in simple mode

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];

// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
// List multipart uploads.
OBSListMultipartUploadsRequest *request = [[OBSListMultipartUploadsRequest alloc]initWithBucketName:@"bucketname"];
    
[client listMultipartUploads:request completionHandler:^(OBSListMultipartUploadsResponse *response, NSError *error) {
    NSLog(@"%@",response);
}];

• Information about a maximum of 1000 multipart uploads can be listed each time. If a bucket contains more than 1000 multipart uploads and response.isTruncated is YES, not all uploads are listed. In such cases, you can use response.nextKeyMarker and response.nextUploadIdMarker to obtain the start position for next listing.
• If you want to obtain all multipart uploads in a bucket, you can list them in paging mode.

• Listing all multipart uploads

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];
    
// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
__block OBSListMultipartUploadsResponse *result;
OBSListMultipartUploadsRequest *request = [[OBSListMultipartUploadsRequest alloc]initWithBucketName:@"bucket-ios-test03"];
    
//List all multipart uploads.
do {
    dispatch_semaphore_t sema = dispatch_semaphore_create(0);
    [client listMultipartUploads:request completionHandler:^(OBSListMultipartUploadsResponse *response, NSError *error) {
        result = response;
        NSLog(@"%@",result);
        request.keyMarker = result.nextKeyMarker;
        request.uploadIDMarker = result.nextUploadIDMarker;
        dispatch_semaphore_signal(sema);
        }];
    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
} while (result.isTruncated);

• Listing all multipart uploads in paging mode

The previous sample code (listing 1000 uploads per page) shows a special paging listing mode. The following sample code shows how to specify the number of uploads displayed per page when listing.

static OBSClient *client;
NSString *endPoint = @"your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
char* ak_env = getenv("AccessKeyID");
char* sk_env = getenv("SecretAccessKey");
NSString *AK = [NSString stringWithUTF8String:ak_env];
NSString *SK = [NSString stringWithUTF8String:sk_env];
    
// Initialize identity authentication.
OBSStaticCredentialProvider *credentialProvider = [[OBSStaticCredentialProvider alloc] initWithAccessKey:AK secretKey:SK];
    
//Initialize service configuration.
OBSServiceConfiguration *conf = [[OBSServiceConfiguration alloc] initWithURLString:endPoint credentialProvider:credentialProvider];
    
// Initialize an instance of OBSClient.
client = [[OBSClient alloc] initWithConfiguration:conf];
    
    
__block OBSListMultipartUploadsResponse *result;
    
    
OBSListMultipartUploadsRequest *request = [[OBSListMultipartUploadsRequest alloc]initWithBucketName:@"bucketname"];
    
// Set the number of multipart uploads displayed per page to 100.
request.maxUploads = [NSNumber numberWithInt:100];
    
//List all multipart uploads.
do {
    dispatch_semaphore_t sema = dispatch_semaphore_create(0);
    [client listMultipartUploads:request completionHandler:^(OBSListMultipartUploadsResponse *response, NSError *error) {
        result = response;
        NSLog(@"%@",result);
        request.keyMarker = result.nextKeyMarker;
        request.uploadIDMarker = result.nextUploadIDMarker;
        dispatch_semaphore_signal(sema);
            
    }];
    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
        
} while (result.isTruncated);