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Getting Pre-Signed URLs

Last updated: 2024-02-01 18:01:21

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
Parameter
Description
Type
options
COS request options
Struct
bucket
Bucket name in the format of BucketName-APPID
String
object
Object name
String
expire
Validity time of the signature, in seconds
Int
method
HTTP request method. Enumerated values: HTTP_GET, HTTP_HEAD, HTTP_PUT, HTTP_POST, HTTP_DELETE
Enum
presigned_url
The generated pre-signed URL
String
Response description
Response
Description
Type
code
Error code
Int
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://www.tencentcloud.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.tencentcloud.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.tencentcloud.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.tencentcloud.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://www.tencentcloud.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
Parameter
Description
Type
options
COS request options
Struct
bucket
Bucket name in the format of BucketName-APPID
String
object
Object name
String
expire
Validity time of the signature, in seconds
Int
method
HTTP request method. Enumerated values: HTTP_GET, HTTP_HEAD, HTTP_PUT, HTTP_POST, HTTP_DELETE
Enum
headers
Additional headers of a COS request
Struct
params
Parameters for the COS request
Struct
sign_host
Whether to sign the signature to the host header. You are strongly advised to enable it for security’s sake.
Int
presigned_url
The generated pre-signed URL
String
Response description
Response
Description
Type
code
Error code
Int
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://www.tencentcloud.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.tencentcloud.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.tencentcloud.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.tencentcloud.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://www.tencentcloud.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://www.tencentcloud.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.tencentcloud.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.tencentcloud.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.tencentcloud.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://www.tencentcloud.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;
}
﻿

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tencent cloud

Recent Pages

Getting Pre-Signed URLs

Overview

Getting a Pre-signed Request URL

Generating pre-signed URL

Description

Method prototype

Parameter description

Response description

Pre-signed request samples

Securely Getting a Pre-signed Request URL

Securely generating a pre-signed URL

Description

Method prototype

Parameter description

Response description

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

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

Was this page helpful?

Was this page helpful?

Parameter	Description	Type
options	COS request options	Struct
bucket	Bucket name in the format of `BucketName-APPID`	String
object	Object name	String
expire	Validity time of the signature, in seconds	Int
method	HTTP request method. Enumerated values: `HTTP_GET`, `HTTP_HEAD`, `HTTP_PUT`, `HTTP_POST`, `HTTP_DELETE`	Enum
presigned_url	The generated pre-signed URL	String

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Recent Pages

Getting Pre-Signed URLs

Overview

Getting a Pre-signed Request URL

Generating pre-signed URL

Description

Method prototype

Parameter description

Response description

Pre-signed request samples

Securely Getting a Pre-signed Request URL

Securely generating a pre-signed URL

Description

Method prototype

Parameter description

Response description

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

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

Was this page helpful?

Was this page helpful?

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

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