Object Storage Service:Upload callback (C SDK)

#include "oss_api.h"
#include "aos_http_io.h"
/* Set yourEndpoint to the endpoint of the region where the bucket is located. For example, for the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
const char *endpoint = "yourEndpoint";

/* Specify the bucket name. Example: examplebucket. */
const char *bucket_name = "examplebucket";
/* Specify the full path of the object. The full path cannot include the bucket name. Example: exampledir/exampleobject.txt. */
const char *object_name = "exampledir/exampleobject.txt";
const char *object_content = "More than just cloud.";
/* Set yourRegion to the region where the bucket is located. For example, for the China (Hangzhou) region, set the region to cn-hangzhou. */
const char *region = "yourRegion";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Initialize the aos_string_t type with a char* string. */
    aos_str_set(&options->config->endpoint, endpoint);
    /* Obtain access credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set. */    
    aos_str_set(&options->config->access_key_id, getenv("OSS_ACCESS_KEY_ID"));
    aos_str_set(&options->config->access_key_secret, getenv("OSS_ACCESS_KEY_SECRET"));
    // Configure the following two parameters.
    aos_str_set(&options->config->region, region);
    options->config->signature_version = 4;
    /* Specifies whether a canonical name (CNAME) is used. A value of 0 indicates that no CNAME is used. */
    options->config->is_cname = 0;
    /* Set network parameters, such as the timeout period. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int main(int argc, char *argv[])
{
    aos_pool_t *p = NULL;
    aos_status_t *s = NULL;
    aos_string_t bucket;
    aos_string_t object;
    aos_table_t *headers = NULL;
    oss_request_options_t *options = NULL;
    aos_table_t *resp_headers = NULL;
    aos_list_t resp_body;
    aos_list_t buffer;
    aos_buf_t *content;
    char *buf = NULL;
    int64_t len = 0;
    int64_t size = 0;
    int64_t pos = 0;
    char b64_buf[1024];
    int b64_len;
    /* Use the JSON format. */
    /* (Optional) Set the Host value in the header of the callback request message, such as the Host value configured on your server. */
    char *callback =  "{"
        "\"callbackUrl\":\"http://oss-demo.aliyuncs.com:23450\","
         "\"callbackHost\":\"yourCallbackHost\","
        "\"callbackBody\":\"bucket=${bucket}&object=${object}&size=${size}&mimeType=${mimeType}\","
        "\"callbackBodyType\":\"application/x-www-form-urlencoded\""
        "}";
    /* Call the aos_http_io_initialize method at the program entry to initialize global resources such as the network and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Initialize parameters. */
    aos_pool_create(&p, NULL);
    options = oss_request_options_create(p);
    init_options(options);
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    aos_list_init(&resp_body);
    aos_list_init(&buffer);
    content = aos_buf_pack(options->pool, object_content, strlen(object_content));
    aos_list_add_tail(&content->node, &buffer);
    /* Add the callback to the header. */
    b64_len = aos_base64_encode((unsigned char*)callback, strlen(callback), b64_buf);
    b64_buf[b64_len] = '\0';
    headers = aos_table_make(p, 1);
    apr_table_set(headers, OSS_CALLBACK, b64_buf);
    /* Upload callback. */
    s = oss_do_put_object_from_buffer(options, &bucket, &object, &buffer,
        headers, NULL, NULL, &resp_headers, &resp_body);
    if (aos_status_is_ok(s)) {
        printf("put object from buffer succeeded\n");
    } else {
        printf("put object from buffer failed\n");
    }
    /* Get the buffer length. */
    len = aos_buf_list_len(&resp_body);
    buf = (char *)aos_pcalloc(p, (apr_size_t)(len + 1));
    buf[len] = '\0';
    /* Copy the buffer content to the memory. */
    aos_list_for_each_entry(aos_buf_t, content, &resp_body, node) {
        size = aos_buf_size(content);
        memcpy(buf + pos, content->pos, (size_t)size);
        pos += size;
    }
    /* Release the memory pool. This releases the memory allocated for various resources during the request. */
    aos_pool_destroy(p);
    /* Release the previously allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}