Manage bucket ACLs (C SDK) - Object Storage Service - Alibaba Cloud Documentation Center

A bucket is a container for objects stored in Object Storage Service (OSS). All objects in OSS are stored in buckets. This topic describes how to configure and query the access control list (ACL) of a bucket.

Usage 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.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Initialization.
To configure the ACL of a bucket, you must have the oss:PutBucketAcl permission. To query the ACL of a bucket, you must have the oss:GetBucketAcl permission. For more information, see Attach a custom policy to a RAM user.

Set bucket ACLs

The following table describes the bucket ACLs.

Access permission	Description	ACL value
Private	Only the bucket owner and authorized users have read and write permissions on objects in the bucket. Other users cannot access the objects.	OSS_ACL_PRIVATE
Public-read	The bucket owner and authorized users have read and write permissions on objects in the bucket. Other users have only read permissions on the objects. Use this permission with caution.	OSS_ACL_PUBLIC_READ
Public-read-write	All users have read and write permissions on objects in the bucket. Use this permission with caution.	OSS_ACL_PUBLIC_READ_WRITE

The following sample code provides an example on how to configure the ACL of a bucket:

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

/* Replace with your bucket name. For example, examplebucket. */
const char *bucket_name = "examplebucket";
/* Replace yourRegion with the region where the bucket is located. For example, if the bucket is 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);
    /* Initialize an aos_string_t type with a char* string. */
    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"));
    // You must also configure the following two parameters.
    aos_str_set(&options->config->region, region);
    options->config->signature_version = 4;
    /* Specify whether to use a CNAME to access OSS. A value of 0 indicates that a CNAME is not 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[])
{
    /* At the program entry, call the aos_http_io_initialize method to initialize global resources such as the network and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* The memory pool (pool) is used for memory management and is equivalent to apr_pool_t. The implementation code is in the apr library. */
    aos_pool_t *pool;
    /* Create a new memory pool. The second parameter is NULL, which indicates that the new memory pool does not inherit from another memory pool. */
    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 memory to options in the memory pool. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize the client option oss_client_options. */
    init_options(oss_client_options);
    /* Initialize parameters. */
    aos_string_t bucket;
    aos_table_t *resp_headers = NULL; 
    aos_status_t *resp_status = NULL; 
    /* Assign the char* data to the aos_string_t bucket. */
    aos_str_set(&bucket, bucket_name);
    /* Set the bucket ACL 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 is equivalent to releasing the memory allocated to resources during the request. */
    aos_pool_destroy(pool);
    /* Release the previously allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Get bucket ACLs

The following sample code provides an example on how to query the ACL of a bucket:

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

/* Replace with your bucket name. For example, examplebucket. */
const char *bucket_name = "examplebucket";
/* Replace yourRegion with the region where the bucket is located. For example, if the bucket is 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);
    /* Initialize an aos_string_t type with a char* string. */
    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"));
    // You must also configure the following two parameters.
    aos_str_set(&options->config->region, region);
    options->config->signature_version = 4;
    /* Specify whether to use a CNAME to access OSS. A value of 0 indicates that a CNAME is not 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[])
{
    /* At the program entry, call the aos_http_io_initialize method to initialize global resources such as the network and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* The memory pool (pool) is used for memory management and is equivalent to apr_pool_t. The implementation code is in the apr library. */
    aos_pool_t *pool;
    /* Create a new memory pool. The second parameter is NULL, which indicates that the new memory pool does not inherit from another memory pool. */
    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 memory to options in the memory pool. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize the client option oss_client_options. */
    init_options(oss_client_options);
    /* Initialize parameters. */
    aos_string_t bucket;
    aos_string_t oss_acl;
    aos_table_t *resp_headers = NULL; 
    aos_status_t *resp_status = NULL; 
    /* Assign the char* data to the aos_string_t bucket. */
    aos_str_set(&bucket, bucket_name);
    /* Get the bucket ACL. */
    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 is equivalent to releasing the memory allocated to resources during the request. */
    aos_pool_destroy(pool);
    /* Release the previously allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

References

For more information about the API operation to set a bucket ACL, see PutBucketAcl.
For more information about the API operation to retrieve a bucket ACL, see GetBucketAcl.