Object Storage Service:Resumable download

import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
        String objectName = "exampledir/exampleobject.txt";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
        try {
            // Perform resumable download in which 10 parts can be concurrently downloaded. 
            DownloadFileRequest downloadFileRequest = new DownloadFileRequest(bucketName, objectName);
            // Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. 
            downloadFileRequest.setDownloadFile("D:\\localpath\\examplefile.txt");
            // Specify the size of each part. Unit: bytes. Valid values: 100 KB to 5 GB. Default value: 100 KB. 
            downloadFileRequest.setPartSize(1 * 1024 * 1024);
            // Specify the number of concurrent threads for the resumable download task. Default value: 1. 
            downloadFileRequest.setTaskNum(10);
            // Specify whether to enable resumable download. By default, resumable upload is disabled. 
            downloadFileRequest.setEnableCheckpoint(true);
            // Specify the full path of the checkpoint file. Example: D:\\localpath\\examplefile.txt.dcp. 
            // The checkpoint file is generated when the object download is interrupted. If you want to download the object by using resumable download, you must specify the full path of the checkpoint file. After the object is downloaded, the checkpoint file is deleted. 
            //downloadFileRequest.setCheckpointFile("D:\\localpath\\examplefile.txt.dcp");

            // Download the object. 
            DownloadFileResult downloadRes = ossClient.downloadFile(downloadFileRequest);
            // After the object is downloaded, the object metadata is returned. 
            ObjectMetadata objectMetadata = downloadRes.getObjectMetadata();
            System.out.println(objectMetadata.getETag());
            System.out.println(objectMetadata.getLastModified());
            System.out.println(objectMetadata.getUserMetadata().get("meta"));
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (Throwable ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

# -*- coding: utf-8 -*-
import oss2
# The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
auth = oss2.Auth('yourAccessKeyId', 'yourAccessKeySecret')
# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
# Specify the name of the bucket. Example: examplebucket. 
bucket = oss2.Bucket(auth, 'https://oss-cn-hangzhou.aliyuncs.com', 'examplebucket')

# Set yourObjectName to the full path of the object. The full path cannot contain the bucket name. Example: exampledir/exampleobject.txt. 
# Set yourLocalFile to the full path of the local file. Example: D:\\localpath\\examplefile.txt. 
oss2.resumable_download(bucket, 'exampledir/exampleobject.txt', 'D:\\localpath\\examplefile.txt')
# If you do not specify a directory by using the store parameter, the .py-oss-upload directory is created in the HOME directory to store the checkpoint information. 

# Optional. You can configure the following parameters in OSS SDK for Python version 2.1.0 and later. 
# import sys
# # If you cannot determine the length of data that you want to download, the value of total_bytes is None. 
# def percentage(consumed_bytes, total_bytes):
#     if total_bytes:
#         rate = int(100 * (float(consumed_bytes) / float(total_bytes)))
#         print('\r{0}% '.format(rate), end='')
#         sys.stdout.flush()
# # If you use the store parameter to specify a directory, the checkpoint information is stored in the specified directory. If you use the num_threads parameter to specify the number of concurrent download threads, make sure that the value of oss2.defaults.connection_pool_size is greater than or equal to the number of concurrent download threads. By default, the number of concurrent threads is 1. 
# oss2.resumable_download(bucket,  'exampledir/exampleobject.txt', 'D:\\localpath\\examplefile.txt',
#                       store=oss2.ResumableDownloadStore(root='/tmp'),
#                       # Specify that resumable download is used when the length of the object is greater than or equal to the value of the multipart_threshold parameter. The multipart_threshold parameter is optional and its default value is 10 MB. 
#                       multiget_threshold=100*1024,
#                       # Specify the size of each part. Unit: bytes. Valid values: 100 KB to 5 GB. Default value: 100 KB. 
#                       part_size=100*1024,
#                       # Configure the callback function that you want to use to indicate the progress of the resumable download task. 
#                       progress_callback=percentage,
#                       # If you use num_threads to set the number of cocurrent download threads, set oss2.defaults.connection_pool_size to a value that is greater than or equal to the number of concurrent download threads. By default, the number of concurrent threads is 1. 
#                       num_threads=4)

using Aliyun.OSS;
using Aliyun.OSS.Common;

// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
var endpoint = "yourEndpoint";
// The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
var accessKeyId = "yourAccessKeyId";
var accessKeySecret = "yourAccessKeySecret";
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
var objectName = "exampleobject.txt";
// Download the object to D:\\localpath as a local file named examplefile.txt. If a file that has the same name already exists, the downloaded object overwrites the file. Otherwise, the downloaded object is saved in the path. 
// If you do not specify the path of the local file, the downloaded object is saved to the path of the project to which the sample program belongs. 
var downloadFilename = "D:\\localpath\\examplefile.txt";
// Specify the full path of the checkpoint file. Example: D:\\localpath\\examplefile.txt.dcp. 
// The checkpoint file is generated when the object download is interrupted. If you want to resume the download task, you must specify the full path of the checkpoint file. After the object is downloaded, the checkpoint file is deleted. 
var checkpointDir = "D:\\localpath\\examplefile.txt.dcp";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Use DownloadObjectRequest to configure multiple parameters. 
    DownloadObjectRequest request = new DownloadObjectRequest(bucketName, objectName, downloadFilename)
    {
        // Specify the size of each part that you want to download. Unit: bytes. 
        PartSize = 8 * 1024 * 1024,
        // Specify the number of concurrent threads. 
        ParallelThreadCount = 3,
        // checkpointDir is a file used to store information about the resumable download progress. If a part fails to be downloaded, you can resume the download task based on the progress that is recorded in the checkpointDir file. If you set checkpointDir to null, resumable download does not take effect and the object is re-downloaded if the object fails to be downloaded. 
        CheckpointDir = checkpointDir,
    };
    // Start the resumable download. 
    client.ResumableDownloadObject(request);
    Console.WriteLine("Resumable download object:{0} succeeded", objectName);
}
catch (OssException ex)
{
    Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
        ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}

package main

import (
    "fmt"
    "os"
    "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
    // Create an OSSClient instance. 
    // Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
    // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
    client, err := oss.New("yourEndpoint", "yourAccessKeyId", "yourAccessKeySecret")
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }

    // Specify the name of the bucket. Example: examplebucket. 
    bucket, err := client.Bucket("examplebucket")
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    
    // Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
    // Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. If you do not specify the path of the local file, the downloaded object is saved to the path of the project to which the sample program belongs. 
    // Set the size of each part that you want to download to 100 KB (100 x 1024) and set the number of concurrent download parts to 3. 
    // oss.Checkpoint(true, "") indicates that resumable download is enabled, and that the checkpoint file is named file.cp and stored in the same directory as the object that you download. file is a variable that indicates the local file name. You can also use oss.Checkpoint(true, "your-cp-file.cp") to specify the checkpoint file. 
    err = bucket.DownloadFile("exampledir/exampleobject.txt", "D:\\localpath\\examplefile.txt", 100*1024, oss.Routines(3), oss.Checkpoint(true, ""))
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
}        

#import "DownloadService.h"
#import "OSSTestMacros.h"

@implementation DownloadRequest

@end

@implementation Checkpoint

- (instancetype)copyWithZone:(NSZone *)zone {
    Checkpoint *other = [[[self class] allocWithZone:zone] init];

    other.etag = self.etag;
    other.totalExpectedLength = self.totalExpectedLength;

    return other;
}

@end


@interface DownloadService()<NSURLSessionTaskDelegate, NSURLSessionDataDelegate>

@property (nonatomic, strong) NSURLSession *session;         // The network session. 
@property (nonatomic, strong) NSURLSessionDataTask *dataTask;   // The data request task. 
@property (nonatomic, copy) DownloadFailureBlock failure;    // The request error. 
@property (nonatomic, copy) DownloadSuccessBlock success;    // The request is successful. 
@property (nonatomic, copy) DownloadProgressBlock progress;  // The download progress. 
@property (nonatomic, copy) Checkpoint *checkpoint;        // The checkpoint file. 
@property (nonatomic, copy) NSString *requestURLString;    // The object resource URL used in a download request. 
@property (nonatomic, copy) NSString *headURLString;       // The object resource URL used in a HEAD request. 
@property (nonatomic, copy) NSString *targetPath;     // The path to which the object is stored. 
@property (nonatomic, assign) unsigned long long totalReceivedContentLength; // The size of the downloaded content. 
@property (nonatomic, strong) dispatch_semaphore_t semaphore;

@end

@implementation DownloadService

- (instancetype)init
{
    self = [super init];
    if (self) {
        NSURLSessionConfiguration *conf = [NSURLSessionConfiguration defaultSessionConfiguration];
        conf.timeoutIntervalForRequest = 15;

        NSOperationQueue *processQueue = [NSOperationQueue new];
        _session = [NSURLSession sessionWithConfiguration:conf delegate:self delegateQueue:processQueue];
        _semaphore = dispatch_semaphore_create(0);
        _checkpoint = [[Checkpoint alloc] init];
    }
    return self;
}
// DownloadRequest is the core of the download logic. 
+ (instancetype)downloadServiceWithRequest:(DownloadRequest *)request {
    DownloadService *service = [[DownloadService alloc] init];
    if (service) {
        service.failure = request.failure;
        service.success = request.success;
        service.requestURLString = request.sourceURLString;
        service.headURLString = request.headURLString;
        service.targetPath = request.downloadFilePath;
        service.progress = request.downloadProgress;
        if (request.checkpoint) {
            service.checkpoint = request.checkpoint;
        }
    }
    return service;
}

/**
 * Obtain object information by using the Head method. OSS compares the ETag of the object with the ETag stored in the local checkpoint file and returns the comparison result. 
 */
- (BOOL)getFileInfo {
    __block BOOL resumable = NO;
    NSURL *url = [NSURL URLWithString:self.headURLString];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:url];
    [request setHTTPMethod:@"HEAD"];
    // Process the information about the object. For example, the ETag is used for precheck during resumable upload, and the content-length header is used to calculate the download progress. 
    NSURLSessionDataTask *task = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if (error) {
            NSLog(@"Failed to obtain Object Meta. error: %@", error);
        } else {
            NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
            NSString *etag = [httpResponse.allHeaderFields objectForKey:@"Etag"];
            if ([self.checkpoint.etag isEqualToString:etag]) {
                resumable = YES;
            } else {
                resumable = NO;
            }
        }
        dispatch_semaphore_signal(self.semaphore);
    }];
    [task resume];

    dispatch_semaphore_wait(self.semaphore, DISPATCH_TIME_FOREVER);
    return resumable;
}

/**
 * Query the size of the local file. 
 */
- (unsigned long long)fileSizeAtPath:(NSString *)filePath {
    unsigned long long fileSize = 0;
    NSFileManager *dfm = [NSFileManager defaultManager];
    if ([dfm fileExistsAtPath:filePath]) {
        NSError *error = nil;
        NSDictionary *attributes = [dfm attributesOfItemAtPath:filePath error:&error];
        if (!error && attributes) {
            fileSize = attributes.fileSize;
        } else if (error) {
            NSLog(@"error: %@", error);
        }
    }

    return fileSize;
}

- (void)resume {
    NSURL *url = [NSURL URLWithString:self.requestURLString];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:url];
    [request setHTTPMethod:@"GET"];

    BOOL Resumable= [self getFileInfo]; // If the value of the resumable field is NO, the resumable download condition is not met. 
    if (resumable) {
        self.totalReceivedContentLength = [self fileSizeAtPath:self.targetPath];
        NSString *requestRange = [NSString stringWithFormat:@"bytes=%llu-", self.totalReceivedContentLength];
        [request setValue:requestRange forHTTPHeaderField:@"Range"];
    } else {
        self.totalReceivedContentLength = 0;
    }

    if (self.totalReceivedContentLength == 0) {
        [[NSFileManager defaultManager] createFileAtPath:self.targetPath contents:nil attributes:nil];
    }

    self.dataTask = [self.session dataTaskWithRequest:request];
    [self.dataTask resume];
}

- (void)pause {
    [self.dataTask cancel];
    self.dataTask = nil;
}

- (void)cancel {
    [self.dataTask cancel];
    self.dataTask = nil;
    [self removeFileAtPath: self.targetPath];
}

- (void)removeFileAtPath:(NSString *)filePath {
    NSError *error = nil;
    [[NSFileManager defaultManager] removeItemAtPath:self.targetPath error:&error];
    if (error) {
        NSLog(@"remove file with error : %@", error);
    }
}

#pragma mark - NSURLSessionDataDelegate

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task
// Check whether the download task is complete and return the result to the upper-layer service. 
didCompleteWithError:(nullable NSError *)error {
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)task.response;
    if ([httpResponse isKindOfClass:[NSHTTPURLResponse class]]) {
        if (httpResponse.statusCode == 200) {
            self.checkpoint.etag = [[httpResponse allHeaderFields] objectForKey:@"Etag"];
            self.checkpoint.totalExpectedLength = httpResponse.expectedContentLength;
        } else if (httpResponse.statusCode == 206) {
            self.checkpoint.etag = [[httpResponse allHeaderFields] objectForKey:@"Etag"];
            self.checkpoint.totalExpectedLength = self.totalReceivedContentLength + httpResponse.expectedContentLength;
        }
    }

    if (error) {
        if (self.failure) {
            NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithDictionary:error.userInfo];
            [userInfo oss_setObject:self.checkpoint forKey:@"checkpoint"];

            NSError *tError = [NSError errorWithDomain:error.domain code:error.code userInfo:userInfo];
            self.failure(tError);
        }
    } else if (self.success) {
        self.success(@{@"status": @"success"});
    }
}

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)dataTask.response;
    if ([httpResponse isKindOfClass:[NSHTTPURLResponse class]]) {
        if (httpResponse.statusCode == 200) {
            self.checkpoint.totalExpectedLength = httpResponse.expectedContentLength;
        } else if (httpResponse.statusCode == 206) {
            self.checkpoint.totalExpectedLength = self.totalReceivedContentLength +  httpResponse.expectedContentLength;
        }
    }

    completionHandler(NSURLSessionResponseAllow);
}
// Write the received network data to the object by using append upload and update the download progress. 
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {

    NSFileHandle *fileHandle = [NSFileHandle fileHandleForWritingAtPath:self.targetPath];
    [fileHandle seekToEndOfFile];
    [fileHandle writeData:data];
    [fileHandle closeFile];

    self.totalReceivedContentLength += data.length;
    if (self.progress) {
        self.progress(data.length, self.totalReceivedContentLength, self.checkpoint.totalExpectedLength);
    }
}

@end

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize the information about the account that is used to access OSS. */
    /* The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. */
    std::string AccessKeyId = "yourAccessKeyId";
    std::string AccessKeySecret = "yourAccessKeySecret";
    /* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
    /* Specify the name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. */
    std::string ObjectName = "exampledir/exampleobject.txt";
    /* Download the object to the local path D:\\localpath and save the downloaded object as a local file named examplefile.txt. If a file that has the same name already exists in the specified path, the downloaded object overwrites the file. Otherwise, the downloaded object is saved in the path. */
    /* If you do not specify a local path for the downloaded object, the downloaded object is saved to the path of the project to which the sample program belongs. */
    std::string DownloadFilePath = "D:\\localpath\\examplefile.txt";
    /* Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt.dcp. */
    /* After the checkpoint file is generated because the object download is interrupted, you must set the full path of the checkpoint file only when you want to continue the download of the object. After the object is downloaded, the checkpoint file is deleted. */
    std::string CheckpointFilePath = "D:\\localpath\\examplefile.txt.dcp";

    /* Initialize the resources such as networks. */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);

    /* Start the resumable download. */
    DownloadObjectRequest request(BucketName, ObjectName, DownloadFilePath, CheckpointFilePath);
    auto outcome = client.ResumableDownloadObject(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "ResumableDownloadObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release resources such as networks. */
    ShutdownSdk();
    return 0;
}

#include "oss_api.h"
#include "aos_http_io.h"
/* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
const char *endpoint = "yourEndpoint";
/* The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in Object Storage Service (OSS) is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. */
const char *access_key_id = "yourAccessKeyId";
const char *access_key_secret = "yourAccessKeySecret";
/* Specify the name of the bucket. Example: examplebucket. */
const char *bucket_name = "examplebucket";
/* Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. */
const char *object_name = "exampledir/exampleobject.txt";
/* Specify the full path of the local file. */
const char *local_filename = "yourLocalFilename";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Use a char* string to initialize data of the aos_string_t type. */
    aos_str_set(&options->config->endpoint, endpoint);
    aos_str_set(&options->config->access_key_id, access_key_id);
    aos_str_set(&options->config->access_key_secret, access_key_secret);
    /* Specify whether to use CNAME. The value 0 indicates that CNAME is not used. */
    options->config->is_cname = 0;
    /* Configure network parameters, such as the timeout period. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int main(int argc, char *argv[])
{
    /* Call the aos_http_io_initialize method in main() to initialize global resources, such as network resources and memory resources. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Create a memory pool to manage memory. aos_pool_t is equivalent to apr_pool_t. The code that is used to create a memory pool is included in the APR library. */
    aos_pool_t *pool;
    /* Create a memory pool. The value of the second parameter is NULL. This value indicates that the pool does not inherit other memory pools. */
    aos_pool_create(&pool, NULL);
    /* Create and initialize options. This parameter includes global configuration information, such as endpoint, access_key_id, access_key_secret, is_cname, and curl. */
    oss_request_options_t *oss_client_options;
    /* Allocate the memory resources in the memory pool to the options. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize oss_client_options. */
    init_options(oss_client_options);
    /* Initialize the parameters. */
    aos_string_t bucket;
    aos_string_t object;
    aos_string_t file;
    aos_table_t *headers = NULL;
    aos_table_t *resp_headers = NULL; 
    aos_status_t *resp_status = NULL; 
    oss_resumable_clt_params_t *clt_params;
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    aos_str_set(&file, local_filename);
    /* Perform resumable download to download the object. */
    clt_params = oss_create_resumable_clt_params_content(pool, 1024 * 100, 3, AOS_TRUE, NULL);
    resp_status = oss_resumable_download_file(oss_client_options, &bucket, &object, &file, headers, NULL, clt_params, NULL, &resp_headers);
    if (aos_status_is_ok(resp_status)) {
        printf("download succeeded\n");
    } else {
        printf("download failed\n");
    }
    /* Release the memory pool. This operation releases the memory resources that are allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

require 'aliyun/oss'

client = Aliyun::OSS::Client.new(
  # In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
  endpoint: 'https://oss-cn-hangzhou.aliyuncs.com',
  # The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
  access_key_id: 'AccessKeyId', access_key_secret: 'AccessKeySecret')

# Specify the name of the bucket. Example: examplebucket. 
bucket = client.get_bucket('examplebucket')
# Specify the full paths of the object and the local file. The full path of the object cannot contain the bucket name. 
bucket.resumable_download('my-object', 'local-file') do |p|
  puts "Progress: #{p}"
end

bucket.resumable_download(
  'my-object', 'local-file',
  :part_size => 100 * 1024, :cpt_file => '/tmp/x.cpt') { |p|
  puts "Progress: #{p}"
}