Configure and query bucket ACLs using C SDK - Object Storage Service - Alibaba Cloud - Object Storage Service

Set and get bucket ACLs to control read and write permissions on the objects in a bucket.

Notes

In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions and endpoints.
This topic demonstrates creating an OSSClient instance with an OSS endpoint. For alternative configurations, such as using a custom domain or authenticating with credentials from Security Token Service (STS), see Initialization (C SDK).
To set the ACL of a bucket, you must have the oss:PutBucketAcl permission. To get the ACL of a bucket, you must have the oss:GetBucketAcl permission. For more information, see Grant a custom policy.

Configure the ACL of a bucket

OSS supports the following bucket ACLs.

ACL	Description	Value
Private	Only the bucket owner and authorized users have read and write permissions on objects in the bucket. Other users cannot access objects in the bucket.	OSS_ACL_PRIVATE
Public-read	Only the bucket owner and authorized users have read and write permissions on objects in the bucket. Other users have only read permissions on objects in the bucket. Exercise caution when you set the bucket ACL to this value.	OSS_ACL_PUBLIC_READ
Public-read-write	All users have read and write permissions on objects in the bucket. Exercise caution when you set the bucket ACL to this value.	OSS_ACL_PUBLIC_READ_WRITE

The following code sets a bucket ACL:

#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";

/* Specify the name of the bucket. Example: examplebucket. */
const char *bucket_name = "examplebucket";
/* Specify the region in which the bucket is located. For example, if the bucket is located in 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);
    /* Use a char* string to initialize data of the aos_string_t type. */
    aos_str_set(&options->config->endpoint, endpoint);
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */    
    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"));
    // Specify two additional parameters.
    aos_str_set(&options->config->region, region);
    options->config->signature_version = 4;
    /* Specify whether to use CNAME to access OSS. 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 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_table_t *resp_headers = NULL; 
    aos_status_t *resp_status = NULL; 
    /* Assign char* data to a bucket of the aos_string_t type. */
    aos_str_set(&bucket, bucket_name);
    /* Set the ACL of the bucket to public-read (OSS_ACL_PUBLIC_READ). */
    resp_status = oss_put_bucket_acl(oss_client_options, &bucket, OSS_ACL_PUBLIC_READ, &resp_headers);
    if (aos_status_is_ok(resp_status)) {
        printf("set bucket acl succeeded\n");
    } else {
        printf("set bucket acl failed\n");
    }
    /* Release the memory pool. This operation releases the memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Query the ACL of a bucket

The following code gets the bucket ACL:

#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";

/* Specify the name of the bucket. Example: examplebucket. */
const char *bucket_name = "examplebucket";
/* Specify the region in which the bucket is located. For example, if the bucket is located in 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);
    /* Use a char* string to initialize data of the aos_string_t type. */
    aos_str_set(&options->config->endpoint, endpoint);
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */    
    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"));
    // Specify two additional parameters.
    aos_str_set(&options->config->region, region);
    options->config->signature_version = 4;
    /* Specify whether to use CNAME to access OSS. 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 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 oss_acl;
    aos_table_t *resp_headers = NULL; 
    aos_status_t *resp_status = NULL; 
    /* Assign char* data to a bucket of the aos_string_t type. */
    aos_str_set(&bucket, bucket_name);
    /* Query the ACL of the bucket. */
    resp_status = oss_get_bucket_acl(oss_client_options, &bucket, &oss_acl, &resp_headers);
    if (aos_status_is_ok(resp_status)) {
        printf("get bucket acl succeeded : %s \n", oss_acl.data);
    } else {
        printf("get bucket acl failed\n");
    }
    /* Release the memory pool. This operation releases the memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

References

For more information about the API operation that you can call to configure the ACL of a bucket, see PutBucketAcl.
For more information about the API operation that you can call to query the ACL of a bucket, see GetBucketAcl.