tencent cloud

Overview

The C SDK provides APIs to obtain pre-signed URLs. For detailed directions, see the description and examples below.

Note：

• You are advised to use a temporary key to generate a pre-signed URL for the security of your requests such as uploads and downloads. When you apply for a temporary key, follow the Principle of Least Privilege to avoid leaking resources besides your buckets and objects.
• If you need to use a permanent key to generate a pre-signed URL, you are advised to limit the permission of the permanent key to uploads and downloads only to avoid risks.

Getting a Pre-signed Request URL

Generating pre-signed URL

Description

This API is used to generate a pre-signed URL.

Method prototype

int cos_gen_presigned_url(const cos_request_options_t *options,
                        const cos_string_t *bucket, 
                        const cos_string_t *object,
                        const int64_t expire,
                        http_method_e method,
                        cos_string_t *presigned_url);

Parameter description

Response description

Pre-signed request samples

You can obtain a pre-signed URL by setting a permanent or temporary key using the options parameter.

#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"
// `endpoint` is the COS access domain name. For more information, see https://intl.cloud.tencent.com/document/product/436/6224.
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// A developer-owned secret ID/key used for the project. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char *TEST_ACCESS_KEY_ID;                // Your SecretId
static char *TEST_ACCESS_KEY_SECRET;            // Your SecretKey
// A unique user-level resource identifier for COS access. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char TEST_APPID[] = "<APPID>";    // Your APPID
// COS bucket name, in the format of [bucket]-[appid], for example `mybucket-1253666666`. It can be obtained at https://console.intl.cloud.tencent.com/cos5/bucket.
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";
// A unique identifier of an object stored in COS. For more information about objects and object keys, please see https://intl.cloud.tencent.com/document/product/436/13324.
static char TEST_OBJECT_NAME1[] = "1.txt";
void init_test_config(cos_config_t *config, int is_cname)
{
  cos_str_set(&config->endpoint, TEST_COS_ENDPOINT);
  cos_str_set(&config->access_key_id, TEST_ACCESS_KEY_ID);
  cos_str_set(&config->access_key_secret, TEST_ACCESS_KEY_SECRET);
  cos_str_set(&config->appid, TEST_APPID);
  config->is_cname = is_cname;
}
void init_test_request_options(cos_request_options_t *options, int is_cname)
{
  options->config = cos_config_create(options->pool);
  init_test_config(options->config, is_cname);
  options->ctl = cos_http_controller_create(options->pool, 0);
}
void test_presigned_url()
{
  cos_pool_t *p = NULL;
  int is_cname = 0;
  cos_request_options_t *options = NULL;
  cos_string_t bucket;
  cos_string_t object;
  cos_string_t presigned_url;

  cos_pool_create(&p, NULL);
  options = cos_request_options_create(p);
  init_test_request_options(options, is_cname);
  cos_str_set(&bucket, TEST_BUCKET_NAME);
  cos_str_set(&object, TEST_OBJECT_NAME1);
   cos_gen_presigned_url(options, &bucket, &object, 300, HTTP_GET, &presigned_url);
  printf("presigned_url: %s\n", presigned_url.data);
   cos_pool_destroy(p);

}
int main(int argc, char *argv[])
{
  // Get SecretId and SecretKey from environment variables
  TEST_ACCESS_KEY_ID     = getenv("COS_SECRETID");
  TEST_ACCESS_KEY_SECRET = getenv("COS_SECRETKEY");
    if (cos_http_io_initialize(NULL, 0) != COSE_OK) {
     exit(1);
  }
   // Set the log level. Default value: `COS_LOG_WARN`
  cos_log_set_level(COS_LOG_WARN);
   // Set log output. Default value: `stderr`
  cos_log_set_output(NULL);
   test_presigned_url();
   cos_http_io_deinitialize();
   return 0;
}

Securely Getting a Pre-signed Request URL

Securely generating a pre-signed URL

Description

This API is used to securely generate a pre-signed URL.

Method prototype

int cos_gen_presigned_url_safe(const cos_request_options_t *options,
                        const cos_string_t *bucket, 
                        const cos_string_t *object,
                        const int64_t expire,
                        http_method_e method,
                        cos_table_t *headers,
                        cos_table_t *params,
                        int sign_host,
                        cos_string_t *presigned_url);

Parameter description

Response description

Sample request 1. Generate a pre-signed URL with host in the signature

You can obtain a pre-signed URL by setting a permanent or temporary key using the options parameter.

#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"
// `endpoint` is the COS access domain name. For more information, see https://intl.cloud.tencent.com/document/product/436/6224.
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// A developer-owned secret ID/key used for the project. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char *TEST_ACCESS_KEY_ID;                // Your SecretId
static char *TEST_ACCESS_KEY_SECRET;            // Your SecretKey
// A unique user-level resource identifier for COS access. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char TEST_APPID[] = "<APPID>";    // Your APPID
// COS bucket name, in the format of [bucket]-[appid], for example `mybucket-1253666666`. It can be obtained at https://console.intl.cloud.tencent.com/cos5/bucket.
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";
// A unique identifier of an object stored in COS. For more information about objects and object keys, please see https://intl.cloud.tencent.com/document/product/436/13324.
static char TEST_OBJECT_NAME1[] = "1.txt";
void init_test_config(cos_config_t *config, int is_cname)
{
  cos_str_set(&config->endpoint, TEST_COS_ENDPOINT);
  cos_str_set(&config->access_key_id, TEST_ACCESS_KEY_ID);
  cos_str_set(&config->access_key_secret, TEST_ACCESS_KEY_SECRET);
  cos_str_set(&config->appid, TEST_APPID);
  config->is_cname = is_cname;
}
void init_test_request_options(cos_request_options_t *options, int is_cname)
{
  options->config = cos_config_create(options->pool);
  init_test_config(options->config, is_cname);
  options->ctl = cos_http_controller_create(options->pool, 0);
}
void test_safe_presigned_url()
{
  cos_pool_t *p = NULL;
  int is_cname = 0;
  cos_request_options_t *options = NULL;
  cos_string_t bucket;
  cos_string_t object;
  cos_string_t presigned_url;
  cos_table_t *params = NULL;
  cos_table_t *headers = NULL;
  int sign_host = 1;

  cos_pool_create(&p, NULL);
  options = cos_request_options_create(p);
  init_test_request_options(options, is_cname);
  /* You can use a temporary key by setting `sts_token`. When you use a temporary key, you need to set `access_key_id` and `access_key_secret` to its SecretId and SecretKey */
  //cos_str_set(&options->config->sts_token, "MyTokenString");
  cos_str_set(&bucket, TEST_BUCKET_NAME);
  cos_str_set(&object, TEST_OBJECT_NAME1);
   // You are strongly advised to set `sign_host` to `1` to add the `host` header to the signature list by force to prevent unauthorized access.
  cos_gen_presigned_url_safe(options, &bucket, &object, 300, HTTP_GET, headers, params, sign_host, &presigned_url);
  printf("presigned_url_safe: %s\n", presigned_url.data);
   cos_pool_destroy(p);
}
int main(int argc, char *argv[])
{
  // Get SecretId and SecretKey from environment variables
  TEST_ACCESS_KEY_ID     = getenv("COS_SECRETID");
  TEST_ACCESS_KEY_SECRET = getenv("COS_SECRETKEY");
    if (cos_http_io_initialize(NULL, 0) != COSE_OK) {
     exit(1);
  }
   // Set the log level. Default value: `COS_LOG_WARN`
  cos_log_set_level(COS_LOG_WARN);
   // Set log output. Default value: `stderr`
  cos_log_set_output(NULL);
   test_safe_presigned_url();
   cos_http_io_deinitialize();
   return 0;
}

Sample request 2. Generate the pre-signed URL with the signature containing request param and request header

You can obtain a pre-signed URL by setting a permanent or temporary key using the options parameter.

#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"
// `endpoint` is the COS access domain name. For more information, see https://intl.cloud.tencent.com/document/product/436/6224.
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// A developer-owned secret ID/key used for the project. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char *TEST_ACCESS_KEY_ID;                // Your SecretId
static char *TEST_ACCESS_KEY_SECRET;            // Your SecretKey
// A unique user-level resource identifier for COS access. It can be obtained at https://console.intl.cloud.tencent.com/cam/capi.
static char TEST_APPID[] = "<APPID>";    // Your APPID
// COS bucket name, in the format of [bucket]-[appid], for example `mybucket-1253666666`. It can be obtained at https://console.intl.cloud.tencent.com/cos5/bucket.
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";
// A unique identifier of an object stored in COS. For more information about objects and object keys, please see https://intl.cloud.tencent.com/document/product/436/13324.
static char TEST_OBJECT_NAME1[] = "1.txt";
void init_test_config(cos_config_t *config, int is_cname)
{
  cos_str_set(&config->endpoint, TEST_COS_ENDPOINT);
  cos_str_set(&config->access_key_id, TEST_ACCESS_KEY_ID);
  cos_str_set(&config->access_key_secret, TEST_ACCESS_KEY_SECRET);
  cos_str_set(&config->appid, TEST_APPID);
  config->is_cname = is_cname;
}
void init_test_request_options(cos_request_options_t *options, int is_cname)
{
  options->config = cos_config_create(options->pool);
  init_test_config(options->config, is_cname);
  options->ctl = cos_http_controller_create(options->pool, 0);
}
void test_safe_presigned_url()
{
  cos_pool_t *p = NULL;
  int is_cname = 0;
  cos_request_options_t *options = NULL;
  cos_string_t bucket;
  cos_string_t object;
  cos_string_t presigned_url;
  cos_table_t *params = NULL;
  cos_table_t *headers = NULL;
  int sign_host = 1;

  cos_pool_create(&p, NULL);
  options = cos_request_options_create(p);
  init_test_request_options(options, is_cname);
  /* You can use a temporary key by setting `sts_token`. When you use a temporary key, you need to set `access_key_id` and `access_key_secret` to its SecretId and SecretKey */
  //cos_str_set(&options->config->sts_token, "MyTokenString");
  cos_str_set(&bucket, TEST_BUCKET_NAME);
  cos_str_set(&object, TEST_OBJECT_NAME1);
   // Add your `params` and `headers`
  params = cos_table_make(options->pool, 0);
  //cos_table_add(params, "param1", "value");
  headers = cos_table_make(options->pool, 0);
  //cos_table_add(headers, "header1", "value");
   // You are strongly advised to set `sign_host` to `1` to add the `host` header to the signature list by force to prevent unauthorized access.
  cos_gen_presigned_url_safe(options, &bucket, &object, 300, HTTP_GET, headers, params, sign_host, &presigned_url);
  printf("presigned_url_safe: %s\n", presigned_url.data);
   cos_pool_destroy(p);
}
int main(int argc, char *argv[])
{
  // Get SecretId and SecretKey from environment variables
  TEST_ACCESS_KEY_ID     = getenv("COS_SECRETID");
  TEST_ACCESS_KEY_SECRET = getenv("COS_SECRETKEY");
    if (cos_http_io_initialize(NULL, 0) != COSE_OK) {
     exit(1);
  }
   // Set the log level. Default value: `COS_LOG_WARN`
  cos_log_set_level(COS_LOG_WARN);
   // Set log output. Default value: `stderr`
  cos_log_set_output(NULL);
   test_safe_presigned_url();
   cos_http_io_deinitialize();
   return 0;
}