C++ 实现 fastdfs 上传下载

为了实现C++的FastDFS上传和下载，需要使用FastDFS C客户端API。以下是实现FastDFS上传和下载的步骤：

1.安装FastDFS C客户端API

可以从FastDFS官方网站下载FastDFS C客户端API。下载后，将其解压缩并安装。

2.上传文件

使用FastDFS C客户端API上传文件的步骤如下：

#include "fastdfs_client.h"
#include "fastdfs_client_ex.h"

int main(int argc, char *argv[])
{
    char *conf_filename = "/etc/fdfs/client.conf";
    char *local_filename = "/path/to/local/file";
    char group_name[FDFS_GROUP_NAME_MAX_LEN + 1];
    char remote_filename[4096];
    ConnectionInfo *pTrackerServer;
    int result;
    int64_t file_size;
    FDFSFileInfo file_info;

    // 初始化FastDFS客户端
    if ((result = fdfs_client_init(conf_filename)) != 0) {
        return result;
    }

    // 获取Tracker服务器
    pTrackerServer = tracker_get_connection();
    if (pTrackerServer == NULL) {
        fdfs_client_destroy();
        return errno != 0 ? errno : ECONNREFUSED;
    }

    // 上传文件
    result = fdfs_upload_by_filename(pTrackerServer, NULL, local_filename, NULL, 0, remote_filename, sizeof(remote_filename));
    if (result != 0) {
        printf("upload file fail, error no: %d, error info: %s\n", result, STRERROR(result));
        tracker_disconnect_server_ex(pTrackerServer, true);
        fdfs_client_destroy();
        return result;
    }

    // 获取上传文件的信息
    result = fdfs_get_file_info_ex(pTrackerServer, NULL, remote_filename, strlen(remote_filename), &file_info);
    if (result != 0) {
        printf("get file info fail, error no: %d, error info: %s\n", result, STRERROR(result));
        tracker_disconnect_server_ex(pTrackerServer, true);
        fdfs_client_destroy();
        return result;
    }

    // 打印上传文件的信息
    printf("group name: %s\n", file_info.group_name);
    printf("remote filename: %s\n", file_info.filename);
    printf("file size: %ld\n", file_info.file_size);
    printf("create time: %s\n", formatDatetime(file_info.create_timestamp, "%Y-%m-%d %H:%M:%S", NULL, 0));
    printf("source ip address: %s\n", file_info.source_ip_addr);

    // 断开Tracker服务器连接
    tracker_disconnect_server_ex(pTrackerServer, true);

    // 销毁FastDFS客户端
    fdfs_client_destroy();

    return 0;
}

3.下载文件

使用FastDFS C客户端API下载文件的步骤如下：

#include "fastdfs_client.h"
#include "fastdfs_client_ex.h"

int main(int argc, char *argv[])
{
    char *conf_filename = "/etc/fdfs/client.conf";
    char *local_filename = "/path/to/local/file";
    char group_name[FDFS_GROUP_NAME_MAX_LEN + 1];
    char remote_filename[4096];
    ConnectionInfo *pTrackerServer;
    int result;
    int64_t file_size;
    FDFSFileInfo file_info;

    // 初始化FastDFS客户端
    if ((result = fdfs_client_init(conf_filename)) != 0) {
        return result;
    }

    // 获取Tracker服务器
    pTrackerServer = tracker_get_connection();
    if (pTrackerServer == NULL) {
        fdfs_client_destroy();
        return errno != 0 ? errno : ECONNREFUSED;
    }

    // 下载文件
    result = fdfs_download_file_ex(pTrackerServer, NULL, remote_filename, strlen(remote_filename), 0, &file_size, local_filename);
    if (result != 0) {
        printf("download file fail, error no: %d, error info: %s\n", result, STRERROR(result));
        tracker_disconnect_server_ex(pTrackerServer, true);
        fdfs_client_destroy();
        return result;
    }

    // 断开Tracker服务器连接
    tracker_disconnect_server_ex(pTrackerServer, true);

    // 销毁FastDFS客户端
    fdfs_client_destroy();

    return 0;
}