多段相关接口说明(C SDK)

开发过程中，您有任何问题可以在github上提交issue，或者在华为云对象存储服务论坛中发帖求助。

对于较大文件上传，可以切分成段上传。用户可以在如下的场景内（但不仅限于此）使用分段上传的模式：

上传超过100MB大小的文件。
网络条件较差，和OBS服务端之间的连接经常断开。
上传前无法确定将要上传文件的大小。

分段上传分为如下3个步骤：

分段上传的主要目的是解决大文件上传或网络条件较差的情况。下面的代码示例展示了如何使用分段上传并发上传大文件：

static void test_concurrent_upload_part(char *filename, char *key, uint64_t uploadSliceSize)
{
    obs_status ret_status = OBS_STATUS_BUTT;
    // 创建并初始化option
    obs_options option;
    init_obs_options(&option);
    option.bucket_options.host_name = "<your-endpoint>";
    option.bucket_options.bucket_name = "<Your bucketname>";

    //从环境变量读取ak/sk
    option.bucket_options.access_key = getenv("ACCESS_KEY_ID");
    option.bucket_options.secret_access_key = getenv("SECRET_ACCESS_KEY");
    char *concurrent_upload_id;
    uint64_t uploadSize = uploadSliceSize;                             
    uint64_t filesize =0;                                          
    //初始化结构体put_properties
    obs_put_properties put_properties;
    init_put_properties(&put_properties);
    //大文件信息:文件指针，文件大小，按照分段大小的分段数
    test_upload_file_callback_data data;
    memset(&data, 0, sizeof(test_upload_file_callback_data));
    filesize = get_file_info(filename,&data);
    data.noStatus = 1;
    data.part_size = uploadSize;
    data.part_num = (filesize % uploadSize == 0) ? (filesize / uploadSize) : (filesize / uploadSize +1);
    // 初始化上传段回调函数    
    obs_response_handler Handler =
    { 
         &response_properties_callback, &response_complete_callback 
    };
    // 合并段回调函数
    obs_complete_multi_part_upload_handler complete_multi_handler =
    { 
        {&response_properties_callback,
         &response_complete_callback},
        &CompleteMultipartUploadCallback
    };
    //初始化上传段任务返回uploadId: uploadIdReturn
    char uploadIdReturn[256] = {0};
    int upload_id_return_size = 255;
    initiate_multi_part_upload(&option,key,upload_id_return_size,uploadIdReturn, &putProperties,
            0,&Handler, &ret_status);
    if (OBS_STATUS_OK == ret_status) {
        printf("test init upload part return uploadIdReturn(%s). \n", uploadIdReturn);
        strcpy(concurrent_upload_id,uploadIdReturn);
    }
    else
    {
        printf("test init upload part failed(%s).\n", obs_get_status_name(ret_status));
    }
    // 并发上传
    test_concurrent_upload_file_callback_data *concurrent_upload_file;
    concurrent_upload_file =(test_concurrent_upload_file_callback_data *)malloc(
                    sizeof(test_concurrent_upload_file_callback_data)*(data.part_num+1));
    if(concurrent_upload_file == NULL)
    {
         printf("malloc test_concurrent_upload_file_callback_data failed!!!");
         return ;
    }
    test_concurrent_upload_file_callback_data *concurrent_upload_file_complete =   
                              concurrent_upload_file;
    start_upload_threads(data, concurrent_upload_id,filesize, key, option, concurrent_upload_file_complete);
     // 合并段
    obs_complete_upload_Info *upload_Info = (obs_complete_upload_Info *)malloc(
                sizeof(obs_complete_upload_Info)*data.part_num);
    for(i=0; i<data.part_num; i++)
    {
        upload_Info[i].part_number = concurrent_upload_file_complete[i].part_num;
        upload_Info[i].etag = concurrent_upload_file_complete[i].etag;
    }
    complete_multi_part_upload(&option, key, uploadIdReturn, data.part_num,upload_Info,&putProperties,&complete_multi_handler,&ret_status);
    if (ret_status == OBS_STATUS_OK) {
        printf("test complete upload successfully. \n");
    }
    else
    {
        printf("test complete upload failed(%s).\n", obs_get_status_name(ret_status));
    }
    if(concurrent_upload_file)
    {
        free(concurrent_upload_file);
        concurrent_upload_file = NULL;
    }
    if(upload_Info)
    {
        free(upload_Info);
        upload_Info = NULL;
    }
}