Ao usar o SDK do Object Storage Service (OSS) para C, você deve inicializar as opções de solicitação (oss_request_options_t) e especificar um endpoint.
Inicializar opções de solicitação
Usar o algoritmo de assinatura V4 (recomendado)
Recomendamos o uso do algoritmo de assinatura V4 para maior segurança. Ao inicializar o SDK com a assinatura V4, especifique um endpoint e um ID de região da Alibaba Cloud. O ID da região define o destino da solicitação, como cn-hangzhou. Declare também signature_version = 4. O SDK do OSS para C versão 3.11.0 ou posterior oferece suporte a assinaturas V4.
O exemplo de código a seguir mostra como criar uma instância OSSClient com um endpoint do OSS e o algoritmo de assinatura V4. Para criar uma instância OSSClient com um nome de domínio personalizado ou credenciais de acesso obtidas via STS, modifique o código conforme necessário.
#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 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 the aos_string_t data 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;
/* Specify network parameters. The second parameter in this function specifies the ownership of ctl. By default, the value of the second parameter is 0. */
options->ctl = aos_http_controller_create(options->pool, 0);
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}Usar o algoritmo de assinatura V1 (não recomendado)
Importante
Usar um endpoint do OSS para inicializar as opções de solicitação
O exemplo de código a seguir mostra como usar um endpoint do OSS para inicializar as opções de solicitação:
#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";
void init_options(oss_request_options_t *options)
{
options->config = oss_config_create(options->pool);
/* Use a char* string to initialize aos_string_t. */
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. The second parameter in this function specifies the ownership of ctl. By default, the value of the second parameter is 0. */
options->ctl = aos_http_controller_create(options->pool, 0);
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}Usar um nome de domínio personalizado para inicializar as opções de solicitação
O exemplo de código a seguir mostra como usar um nome de domínio personalizado para inicializar as opções de solicitação:
#include "oss_api.h"
#include "aos_http_io.h"
# Specify the custom domain name. */
const char *endpoint = "yourCustomEndpoint";
void init_options(oss_request_options_t *options) {
options->config = oss_config_create(options->pool);
/* Use a char* string to initialize aos_string_t. */
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"));
/* Enable CNAME and map the custom domain name to your bucket. */
options->config->is_cname = 1;
options->ctl = aos_http_controller_create(options->pool, 0);
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}Usar credenciais de acesso temporárias fornecidas pelo STS para inicializar as opções de solicitação
O exemplo de código a seguir mostra como usar credenciais de acesso temporárias obtidas do Security Token Service (STS) para inicializar as opções de solicitação:
#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";
/* Before you run the sample code, make sure that the YOUR_ACCESS_KEY_ID and YOUR_ACCESS_KEY_SECRET environment variables are configured to store temporary access credentials obtained from STS. */
const char *access_key_id = getenv("YOUR_ACCESS_KEY_ID");
const char *access_key_secret = getenv("YOUR_ACCESS_KEY_SECRET");
/* Specify the security token that is obtained from STS. */
const char *sts_token = "<yourSecurityToken>";
void init_options(oss_request_options_t *options)
{
options->config = oss_config_create(options->pool);
/* Use a char* string to initialize aos_string_t. */
aos_str_set(&options->config->endpoint, endpoint);
aos_str_set(&options->config->access_key_id, access_key_id);
aos_str_set(&options->config->access_key_secret, access_key_secret);
/* Set the token. */
aos_str_set(&options->config->sts_token, sts_token);
/* Specify whether to use CNAME. The value 0 indicates that CNAME is not used. */
options->config->is_cname = 0;
options->ctl = aos_http_controller_create(options->pool, 0);
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}Parâmetros
A tabela a seguir descreve os parâmetros comuns.
|
Parâmetro |
Descrição |
|
speed_limit |
Limite inferior da velocidade média. Unidade: bytes/segundo. Valor padrão: 1024. |
|
speed_time |
Duração mínima para o cálculo da velocidade média, em segundos. Valor padrão: 15. Importante
Os parâmetros speed_limit e speed_time são obrigatórios. Se a velocidade média permanecer abaixo do limite definido por speed_limit durante o período especificado em speed_time, a solicitação será interrompida. |
|
connect_timeout |
Tempo limite para estabelecimento de conexão. Unidade: segundos. Valor padrão: 10. |
|
dns_cache_timeout |
Tempo limite do cache DNS. Unidade: segundos. Valor padrão: 60. |
|
max_memory_size |
Tamanho máximo de dados gravados na memória durante o download. Unidade: bytes. Valor padrão: 1 GB. |
|
enable_crc |
Define se o CRC-64 está ativado. Valores válidos:
|
|
verify_ssl |
Define se a autenticação baseada em SSL está ativada. Valores válidos:
|
|
ca_path |
Caminho raiz do certificado CA. Este parâmetro é válido apenas quando verify_ssl está definido como 1. Por padrão, este campo permanece vazio. |
|
ca_file |
Caminho do arquivo de certificado CA. Este parâmetro é válido apenas quando verify_ssl está definido como 1. Por padrão, este campo permanece vazio. |
|
proxy_host |
Endereço do servidor proxy no formato |
|
proxy_auth |
Credenciais de autenticação para o servidor proxy no formato |
Exemplos de configuração
Especificar um tempo limite
O exemplo de código a seguir mostra como especificar um tempo limite:
#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";
void init_options(oss_request_options_t *options)
{
options->config = oss_config_create(options->pool);
/* Use a char* string to initialize aos_string_t. */
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. The second parameter in this function specifies the ownership of ctl. By default, the value of the second parameter is 0. */
options->ctl = aos_http_controller_create(options->pool, 0);
/* Specify the timeout period for establishing a connection. Default value: 10. Unit: seconds. */
options->ctl->options->connect_timeout = 10;
/* Specify the timeout period of the DNS cache. Default value: 60. Unit: seconds. */
options->ctl->options->dns_cache_timeout = 60;
/*
Specify the timeout period.
Configure the speed_limit parameter to specify the lower limit on the average speed. Default value: 1024 (1 KB/s).
Configure the speed_time parameter to specify the allowed maximum time period for an average speed that is less than the lower speed limit. Default value: 15. Unit: seconds.
The following lines specify that a request timeout occurs when the transmission speed is less than 1 KB/s for 15 consecutive seconds:
*/
options->ctl->options->speed_limit = 1024;
options->ctl->options->speed_time = 15;
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}Configurar autenticação baseada em SSL
A autenticação baseada em SSL vem ativada por padrão no SDK do OSS para C a partir da versão 3.9.2. Se a autenticação SSL falhar, verifique se o caminho do certificado SSL está correto ou desative a autenticação SSL.
O exemplo de código a seguir mostra como configurar a autenticação baseada em SSL:
#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";
void init_options(oss_request_options_t *options)
{
options->config = oss_config_create(options->pool);
/* Use a char* string to initialize aos_string_t. */
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. The second parameter in this function specifies the ownership of ctl. By default, the value of the second parameter is 0. */
options->ctl = aos_http_controller_create(options->pool, 0);
/* Configure SSL-based authentication. */
Configure the verify_ssl parameter to specify whether to enable SSL-based authentication. Valid values: 0 and 1. Default value: 1. The value 1 specifies that SSL-based authentication is enabled.
Configure the ca_path parameter to specify the root path of the CA certificate. This parameter is valid when verify_ssl is set to 1. By default, this parameter is left empty.
Configure the ca_file parameter to specify the path of the CA certificate. This parameter is valid when verify_ssl is set to 1. By default, this parameter is left empty. */
/* Enable SSL-based authentication and specify the path of the CA certificate. */
//options->ctl->options->verify_ssl = 1;
//options->ctl->options->ca_path = "/etc/ssl/certs/";
//options->ctl->options->ca_file = "/etc/ssl/certs/ca-certificates.crt";
/* Disable SSL-based authentication. */
//options->ctl->options->verify_ssl = 0;
}
int main() {
aos_pool_t *p;
oss_request_options_t *options;
/* Initialize global variables. You need to initialize global variables only once in the program lifecycle. */
if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
return -1;
}
/* Initialize the memory pool and options. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
/* The logic code. In this example, the logic code is omitted. */
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release global resources that are allocated. You need to release global resources only once in the program lifecycle. */
aos_http_io_deinitialize();
return 0;
}