Cross-origin resource sharing (CORS) is a standard cross-origin solution provided by HTML5 to allow web application servers to control cross-origin access and secure cross-origin data transmission. This topic describes how to use CORS.
Usage notes
OSS SDK for C 3.6.0 and later support CORS.
In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS by using other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about the regions and endpoints supported by OSS, 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 CORS rules, you must have the
oss:PutBucketCorspermission. To query CORS rules, you must have theoss:GetBucketCorspermission. To delete CORS rules, you must have theoss:DeleteBucketCorspermission. For more information, see Attach a custom policy to a RAM user.
Configure CORS rules
The following code provides an example on how to configure CORS rules for a specific bucket:
#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";
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 whether to use CNAME. The value 0 indicates that CNAME is not used. */
options->config->is_cname = 0;
/* Specify 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;
aos_list_t cors_rule_list;
oss_cors_rule_t *cors_rule1 = NULL, *cors_rule2 = NULL;
aos_str_set(&bucket, bucket_name);
aos_list_init(&cors_rule_list);
cors_rule1 = oss_create_cors_rule(pool);
aos_list_add_tail(&cors_rule1->node, &cors_rule_list);
oss_create_sub_cors_rule(pool, &cors_rule1->allowed_origin_list, "allowed_origin_1_1");
oss_create_sub_cors_rule(pool, &cors_rule1->allowed_origin_list, "allowed_origin_1_1");
oss_create_sub_cors_rule(pool, &cors_rule1->allowed_method_list, "PUT");
oss_create_sub_cors_rule(pool, &cors_rule1->allowed_method_list, "GET");
oss_create_sub_cors_rule(pool, &cors_rule1->allowed_head_list, "Authorization");
oss_create_sub_cors_rule(pool, &cors_rule1->expose_head_list, "expose_head_1_1");
oss_create_sub_cors_rule(pool, &cors_rule1->expose_head_list, "expose_head_1_1");
cors_rule2 = oss_create_cors_rule(pool);
aos_list_add_tail(&cors_rule2->node, &cors_rule_list);
oss_create_sub_cors_rule(pool, &cors_rule2->allowed_origin_list, "allowed_origin_2_1");
oss_create_sub_cors_rule(pool, &cors_rule2->allowed_origin_list, "allowed_origin_2_2");
oss_create_sub_cors_rule(pool, &cors_rule2->allowed_method_list, "PUT");
oss_create_sub_cors_rule(pool, &cors_rule2->allowed_method_list, "GET");
oss_create_sub_cors_rule(pool, &cors_rule2->allowed_head_list, "Authorization");
oss_create_sub_cors_rule(pool, &cors_rule2->expose_head_list, "expose_head_2_1");
oss_create_sub_cors_rule(pool, &cors_rule2->expose_head_list, "expose_head_2_2");
/* Configure CORS rules. */
resp_status = oss_put_bucket_cors(oss_client_options, &bucket, &cors_rule_list, &resp_headers);
if (aos_status_is_ok(resp_status)) {
printf("put bucket cors succeeded\n");
} else {
printf("put bucket cors 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 CORS rules
The following code provides an example on how to query the CORS rules that are configured for a specific bucket:
#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";
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 whether to use CNAME. 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;
aos_list_t cors_rule_list;
oss_cors_rule_t *cors_rule = NULL;
oss_sub_cors_rule_t *sub_cors_rule = NULL;
aos_str_set(&bucket, bucket_name);
/* Query CORS rules. */
aos_list_init(&cors_rule_list);
resp_status = oss_get_bucket_cors(oss_client_options, &bucket, &cors_rule_list, &resp_headers);
if (aos_status_is_ok(resp_status)) {
printf("get bucket cors succeeded\n");
aos_list_for_each_entry(oss_cors_rule_t, cors_rule, &cors_rule_list, node) {
printf("max_age_seconds: %d\n", cors_rule->max_age_seconds);
aos_list_for_each_entry(oss_sub_cors_rule_t, sub_cors_rule, &cors_rule->allowed_origin_list, node) {
printf("allowed_origin_list: %s \n", sub_cors_rule->rule.data);
}
aos_list_for_each_entry(oss_sub_cors_rule_t, sub_cors_rule, &cors_rule->allowed_method_list, node) {
printf("allowed_method_list: %s \n", sub_cors_rule->rule.data);
}
aos_list_for_each_entry(oss_sub_cors_rule_t, sub_cors_rule, &cors_rule->allowed_head_list, node) {
printf("allowed_head_list: %s \n", sub_cors_rule->rule.data);
}
aos_list_for_each_entry(oss_sub_cors_rule_t, sub_cors_rule, &cors_rule->expose_head_list, node) {
printf("expose_head_list: %s \n", sub_cors_rule->rule.data);
}
}
} else {
printf("get bucket cors 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;
}Delete CORS rules
The following code provides an example on how to delete the CORS rules that are configured for a specific bucket:
#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";
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 whether to use CNAME. 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;
aos_str_set(&bucket, bucket_name);
/* Delete CORS rules. */
resp_status = oss_delete_bucket_cors(oss_client_options, &bucket, &resp_headers);
if (aos_status_is_ok(resp_status)) {
printf("delete bucket cors succeeded\n");
} else {
printf("delete bucket cors 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 CORS rules, see PutBucketCors.
For more information about the API operation that you can call to query CORS rules, see GetBucketCors.
For more information about the API operation that you can call to delete CORS rules, see DeleteBucketCors.