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简介

本文档提供关于对象列举相关的 API 概览以及 SDK 示例代码。
API
操作名
操作描述
查询对象列表
查询存储桶下的部分或者全部对象

查询对象列表

功能说明

查询存储桶下的部分或者全部对象。

方法原型

cos_status_t *cos_list_object(const cos_request_options_t *options,
const cos_string_t *bucket,
cos_list_object_params_t *params,
cos_table_t **resp_headers);

参数说明

参数名称
参数描述
类型
options
COS 请求选项
Struct
bucket
存储桶名称,Bucket 的命名规则为 BucketName-APPID ,此处填写的存储桶名称必须为此格式
String
params
列表操作参数信息
Struct
encoding_type
规定返回值的编码方式
String
prefix
前缀匹配,用来规定返回的文件前缀地址
String
marker
默认以 UTF-8 二进制顺序列出条目,所有列出条目从 marker 开始
String
delimiter
查询分隔符,用于对对象键进行分组
String
max_ret
单次返回最大的条目数量,默认1000
Struct
truncated
返回条目是否被截断,'true' 或者 'false'
Boolean
next_marker
假如返回条目被截断,则返回 NextMarker 就是下一个条目的起点
String
object_list
Get Bucket 操作返回的对象信息列表
Struct
key
Get Bucket 操作返回的 Object 名称
Struct
last_modified
Get Bucket 操作返回的 Object 最后修改时间
Struct
etag
Get Bucket 操作返回的对象的 SHA-1 算法校验值
Struct
size
Get Bucket 操作返回的对象大小,单位 Byte
Struct
owner_id
Get Bucket 操作返回的对象拥有者 UID 信息
Struct
storage_class
Get Bucket 操作返回的对象存储级别
Struct
common_prefix_list
将 Prefix 到 delimiter 之间的相同路径归为一类,定义为 Common Prefix
Struct
resp_headers
返回 HTTP 响应消息的头域
Struct

返回结果说明

返回结果
描述
类型
code
错误码
Int
error_code
错误码内容
String
error_msg
错误码描述
String
req_id
请求消息 ID
String

示例1:列出第一页对象

#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"

// endpoint 是 COS 访问域名信息,详情请参见 https://cloud.tencent.com/document/product/436/6224 文档
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// 开发者拥有的项目身份ID/密钥,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char *TEST_ACCESS_KEY_ID; //your secret_id
static char *TEST_ACCESS_KEY_SECRET; //your secret_key
// 开发者访问 COS 服务时拥有的用户维度唯一资源标识,用以标识资源,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char TEST_APPID[] = "<APPID>"; //your appid
//the cos bucket name, syntax: [bucket]-[appid], for example: mybucket-1253666666,可在 https://console.cloud.tencent.com/cos5/bucket 查看
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";

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_list_objects()
{
cos_pool_t *p = NULL;
int is_cname = 0;
cos_status_t *s = NULL;
cos_request_options_t *options = NULL;
cos_string_t bucket;
cos_table_t *resp_headers = NULL;

//创建内存池
cos_pool_create(&p, NULL);

//初始化请求选项
options = cos_request_options_create(p);
init_test_request_options(options, is_cname);
cos_str_set(&bucket, TEST_BUCKET_NAME);

//获取对象列表
cos_list_object_params_t *list_params = NULL;
cos_list_object_content_t *content = NULL;
list_params = cos_create_list_object_params(p);
s = cos_list_object(options, &bucket, list_params, &resp_headers);
if (cos_status_is_ok(s)) {
printf("list object succeeded\\n");
cos_list_for_each_entry(cos_list_object_content_t, content, &list_params->object_list, node) {
printf("object: %.*s\\n", content->key.len, content->key.data);
}
} else {
printf("list object failed\\n");
}

//销毁内存池
cos_pool_destroy(p);
}

int main(int argc, char *argv[])
{
// 通过环境变量获取 SECRETID 和 SECRETKEY
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 log level, default COS_LOG_WARN
cos_log_set_level(COS_LOG_WARN);

//set log output, default stderr
cos_log_set_output(NULL);

test_list_objects();

cos_http_io_deinitialize();

return 0;
}

示例2:列出目录下的对象

对象存储中本身是没有文件夹和目录的概念的,为了满足用户使用习惯,用户可通过分隔符/来模拟“文件夹”。
#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"

// endpoint 是 COS 访问域名信息,详情请参见 https://cloud.tencent.com/document/product/436/6224 文档
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// 开发者拥有的项目身份ID/密钥,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char *TEST_ACCESS_KEY_ID; //your secret_id
static char *TEST_ACCESS_KEY_SECRET; //your secret_key
// 开发者访问 COS 服务时拥有的用户维度唯一资源标识,用以标识资源,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char TEST_APPID[] = "<APPID>"; //your appid
//the cos bucket name, syntax: [bucket]-[appid], for example: mybucket-1253666666,可在 https://console.cloud.tencent.com/cos5/bucket 查看
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";

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_list_directory()
{
cos_pool_t *p = NULL;
int is_cname = 0;
cos_status_t *s = NULL;
cos_request_options_t *options = NULL;
cos_string_t bucket;
cos_table_t *resp_headers;
int is_truncated = 1;
cos_string_t marker;

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);

//list object (get bucket)
cos_list_object_params_t *list_params = NULL;
list_params = cos_create_list_object_params(p);
// prefix表示列出的object的key以prefix开始
cos_str_set(&list_params->prefix, "folder/");
// deliter表示分隔符, 设置为/表示列出当前目录下的object, 设置为空表示列出所有的object
cos_str_set(&list_params->delimiter, "/");
// 设置最大遍历出多少个对象, 一次listobject最大支持1000
list_params->max_ret = 1000;
cos_str_set(&marker, "");
while (is_truncated) {
list_params->marker = marker;
s = cos_list_object(options, &bucket, list_params, &resp_headers);
if (!cos_status_is_ok(s)) {
printf("list object failed, req_id:%s\\n", s->req_id);
break;
}
// list_params->object_list 返回列出的object对象。
cos_list_object_content_t *content = NULL;
cos_list_for_each_entry(cos_list_object_content_t, content, &list_params->object_list, node) {
printf("object: %s\\n", content->key.data);
}
// list_params->common_prefix_list 表示被delimiter截断的路径, 如delimter设置为/, common prefix则表示所有子目录的路径
cos_list_object_common_prefix_t *common_prefix = NULL;
cos_list_for_each_entry(cos_list_object_common_prefix_t, common_prefix, &list_params->common_prefix_list, node) {
printf("common prefix: %s\\n", common_prefix->prefix.data);
}

is_truncated = list_params->truncated;
marker = list_params->next_marker;
}
cos_pool_destroy(p);
}

int main(int argc, char *argv[])
{
// 通过环境变量获取 SECRETID 和 SECRETKEY
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 log level, default COS_LOG_WARN
cos_log_set_level(COS_LOG_WARN);

//set log output, default stderr
cos_log_set_output(NULL);

test_list_directory();

cos_http_io_deinitialize();

return 0;
}

示例3:列出桶中的所有对象

一次列举的最大对象数为1000,当桶内对象个数超过1000后,需要去循环列举桶中所有的对象。
#include "cos_http_io.h"
#include "cos_api.h"
#include "cos_log.h"

// endpoint 是 COS 访问域名信息,详情请参见 https://cloud.tencent.com/document/product/436/6224 文档
static char TEST_COS_ENDPOINT[] = "cos.ap-guangzhou.myqcloud.com";
// 开发者拥有的项目身份ID/密钥,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char *TEST_ACCESS_KEY_ID; //your secret_id
static char *TEST_ACCESS_KEY_SECRET; //your secret_key
// 开发者访问 COS 服务时拥有的用户维度唯一资源标识,用以标识资源,可在 https://console.cloud.tencent.com/cam/capi 页面获取
static char TEST_APPID[] = "<APPID>"; //your appid
//the cos bucket name, syntax: [bucket]-[appid], for example: mybucket-1253666666,可在 https://console.cloud.tencent.com/cos5/bucket 查看
static char TEST_BUCKET_NAME[] = "<bucketname-appid>";

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_list_all_objects()
{
cos_pool_t *p = NULL;
int is_cname = 0;
cos_status_t *s = NULL;
cos_request_options_t *options = NULL;
cos_string_t bucket;
cos_table_t *resp_headers;
int is_truncated = 1;
cos_string_t marker;

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);

//list object (get bucket)
cos_list_object_params_t *list_params = NULL;
list_params = cos_create_list_object_params(p);
// 设置最大遍历出多少个对象, 一次listobject最大支持1000
list_params->max_ret = 1000;
cos_str_set(&marker, "");
while (is_truncated) {
list_params->marker = marker;
cos_list_init(&list_params->object_list);
s = cos_list_object(options, &bucket, list_params, &resp_headers);
if (!cos_status_is_ok(s)) {
printf("list object failed, req_id:%s\\n", s->req_id);
break;
}
// list_params->object_list 返回列出的object对象。
cos_list_object_content_t *content = NULL;
cos_list_for_each_entry(cos_list_object_content_t, content, &list_params->object_list, node) {
printf("object: %s\\n", content->key.data);
}

is_truncated = list_params->truncated;
marker = list_params->next_marker;
}
cos_pool_destroy(p);
}

int main(int argc, char *argv[])
{
// 通过环境变量获取 SECRETID 和 SECRETKEY
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 log level, default COS_LOG_WARN
cos_log_set_level(COS_LOG_WARN);

//set log output, default stderr
cos_log_set_output(NULL);

test_list_all_objects();

cos_http_io_deinitialize();

return 0;
}