オブジェクトがアップロードされた後、object Storage Service (OSS) はアプリケーションサーバーにコールバック要求を送信できます。 コールバックを実装するには、関連するコールバックパラメーターを含むリクエストのみをOSSに送信する必要があります。
使用上の注意
このトピックでは、中国 (杭州) リージョンのパブリックエンドポイントを使用します。 OSSと同じリージョンにある他のAlibaba CloudサービスからOSSにアクセスする場合は、内部エンドポイントを使用します。 OSSリージョンとエンドポイントの詳細については、「リージョンとエンドポイント」をご参照ください。
このトピックでは、OSSエンドポイントを使用してOSSClientインスタンスを作成します。 カスタムドメイン名またはSTS (Security Token Service) を使用してOSSClientインスタンスを作成する場合は、「初期化」をご参照ください。
例
次のサンプルコードは、アップロードコールバックを設定する方法の例を示しています。
#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";
/* Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. */
const char *object_name = "exampledir/exampleobject.txt";
const char *object_content = "More than just cloud.";
/* 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 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 two additional parameters.
aos_str_set(&options->config->region, region);
options->config->signature_version = 4;
/* 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[])
{
aos_pool_t *p = NULL;
aos_status_t *s = NULL;
aos_string_t bucket;
aos_string_t object;
aos_table_t *headers = NULL;
oss_request_options_t *options = NULL;
aos_table_t *resp_headers = NULL;
aos_list_t resp_body;
aos_list_t buffer;
aos_buf_t *content;
char *buf = NULL;
int64_t len = 0;
int64_t size = 0;
int64_t pos = 0;
char b64_buf[1024];
int b64_len;
/* Specify the callback parameters in the JSON format. */
/* (Optional) Specify the Host field included in the callback request header. */
char *callback = "{"
"\"callbackUrl\":\"http://oss-demo.aliyuncs.com:23450\","
"\"callbackHost\":\"yourCallbackHost\","
"\"callbackBody\":\"bucket=${bucket}&object=${object}&size=${size}&mimeType=${mimeType}\","
"\"callbackBodyType\":\"application/x-www-form-urlencoded\""
"}";
/* 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);
}
/* Initialize the parameters. */
aos_pool_create(&p, NULL);
options = oss_request_options_create(p);
init_options(options);
aos_str_set(&bucket, bucket_name);
aos_str_set(&object, object_name);
aos_list_init(&resp_body);
aos_list_init(&buffer);
content = aos_buf_pack(options->pool, object_content, strlen(object_content));
aos_list_add_tail(&content->node, &buffer);
/* Add the callback to the header. */
b64_len = aos_base64_encode((unsigned char*)callback, strlen(callback), b64_buf);
b64_buf[b64_len] = '\0';
headers = aos_table_make(p, 1);
apr_table_set(headers, OSS_CALLBACK, b64_buf);
/* Configure the upload callback. */
s = oss_do_put_object_from_buffer(options, &bucket, &object, &buffer,
headers, NULL, NULL, &resp_headers, &resp_body);
if (aos_status_is_ok(s)) {
printf("put object from buffer succeeded\n");
} else {
printf("put object from buffer failed\n");
}
/* Obtain the buffer length. */
len = aos_buf_list_len(&resp_body);
buf = (char *)aos_pcalloc(p, (apr_size_t)(len + 1));
buf[len] = '\0';
/* Copy the content in the buffer to the memory. */
aos_list_for_each_entry(aos_buf_t, content, &resp_body, node) {
size = aos_buf_size(content);
memcpy(buf + pos, content->pos, (size_t)size);
pos += size;
}
/* Release the memory pool. This operation releases the memory resources allocated for the request. */
aos_pool_destroy(p);
/* Release the allocated global resources. */
aos_http_io_deinitialize();
return 0;
}