How to implement breakpoint resume using COS C SDK?

To implement breakpoint resume using the COS (Cloud Object Storage) C SDK, you can utilize the cos_resumable_upload_file function. This function allows you to upload a file in parts and resume the upload from where it left off if interrupted.

Here's a basic example of how to use this function:

1. Initialize COS Client: First, you need to initialize the COS client with your credentials and configuration.

2. Set Up Resume Parameters: Define the parameters for resumable upload, including the file path, bucket name, object key, and other necessary settings.

3. Call cos_resumable_upload_file: Use this function to start or resume the upload process.

Example code snippet:

#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"

int main() {
    // Initialize COS client
    cos_init();

    // Set up COS client configuration
    cos_config_t *config = cos_config_create();
    config->endpoint = "https://your-cos-endpoint";
    config->access_key_id = "your-access-key-id";
    config->access_key_secret = "your-access-key-secret";
    config->appid = "your-appid";

    cos_client_t *client = cos_client_create(config);

    // Set up resumable upload parameters
    cos_resumable_upload_params_t *params = cos_resumable_upload_params_create();
    params->file_path = "path/to/your/file";
    params->bucket = "examplebucket-1250000000";
    params->object = "object_name";
    params->part_size = 1024 * 1024; // 1MB
    params->enableCheckpoint = 1; // Enable checkpoint for resumable upload

    // Perform resumable upload
    cos_status_t *s = cos_resumable_upload_file(client, params, NULL);

    if (cos_status_is_ok(s)) {
        printf("Upload success\n");
    } else {
        printf("Upload failed, error code: %d, error message: %s\n", s->code, s->msg);
    }

    // Clean up
    cos_resumable_upload_params_free(params);
    cos_client_free(client);
    cos_config_free(config);
    cos_cleanup();

    return 0;
}

In this example:

• Initialization: The COS client is initialized with the necessary credentials and endpoint.
• Parameters: The resumable upload parameters are set, including the file path, bucket name, object key, part size, and enabling checkpoints.
• Upload: The cos_resumable_upload_file function is called to start or resume the upload. If the upload is interrupted, it can be resumed from the last checkpoint.

This approach ensures that large file uploads can be completed even if the network connection is lost or the upload process is interrupted.