我正在尝试下载存储在远程计算机上的少量文件。这些文件可以是文本文件,图像文件(jpeg,jpg格式),视频或音频文件。文本文件下载成功没有问题,我也可以在我下载它们的本地机器上打开它。但是下载后图片文件和其他视频,音频文件无法打开。当我检查时,它们与原始文件的大小不同。就像说原始文件是30kb,但下载的文件只有5kb。这就是我下载后可能无法在本地打开这些文件的原因?我正在使用scp
的libssh
功能。以下是我的尝试:
#include <iostream>
#include <string>
#include <libssh.h>
#include <stdlib.h>
#include <fstream>
#include <stdio.h>
#include <Windows.h>
#include <fcntl.h>
#include <sstream>
#include <io.h>
using namespace std;
static int fetch_files(ssh_session session){
int size;
//char buffer[16384];
int mode;
int rc;
//creating scp session to read from remote host for this file
ssh_scp scp = ssh_scp_new(session, SSH_SCP_READ | SSH_SCP_RECURSIVE, "/home/snaps.jpg");
//executing the init
rc = ssh_scp_init(scp);
//pulling from request object
rc = ssh_scp_pull_request(scp);
if (rc != SSH_SCP_REQUEST_NEWFILE)
{
std::cout << "Error receiving information about file: rc != SSH_SCP_REQUEST_NEWFILE";
return -3;
}
else {
//trying to download the file from the created scp object
int t_filesize = ssh_scp_request_get_size(scp);
cout << "filesize is = " << t_filesize;
string t_filename = strdup(ssh_scp_request_get_filename(scp));
cout << "File name read is = " << t_filename;
int t_filemode = ssh_scp_request_get_permissions(scp);
cout << "File mode is = " << t_filemode;
//fprintf(stderr, "Receiving file %s, size %d, permisssions 0%o\n", t_filename, t_filesize, t_filemode);
FILE *fptr = fopen("file.jpg", "w");
if (NULL == fptr)
{
fprintf(stderr, "Error opening local file: %s, error %s\n", t_filename, strerror(errno));
ssh_scp_deny_request(scp, "Unable to open local file");
}
ssh_scp_accept_request(scp);
while (rc >= 0)
{ //reading and storing into buffer to write on local file system
rc = ssh_scp_read(scp, buffer, sizeof(buffer));
cout << "Buffer = " << buffer;
//cout << "RC = " << rc << " and SSH_ERROR is = " << SSH_ERROR;
if (rc == SSH_ERROR)
{
fprintf(stderr, "Error receiving file data: %s\n", ssh_get_error(session));
fclose(fptr);
ssh_scp_close(scp);
ssh_scp_free(scp);
return rc;
}
//fprintf(stderr, "Bytes received = %d\n", rc);
if (fwrite(buffer, rc, 1, fptr) != t_filesize)
{
fprintf(stderr, "Error writing file data: %s\n", strerror(errno));
fclose(fptr);
ssh_scp_close(scp);
ssh_scp_free(scp);
return rc;
}
}
cout << "Buffer is = " << buffer;
fclose(fptr);
}
请让我知道如何解决它。另外,如果您需要任何其他详细信息,请告知我们。
if (fwrite(buffer, rc, 1, fptr) != t_filesize)
本来应该
if (fwrite(buffer, 1, rc, fptr) != rc)
要么
if (fwrite(buffer, rc, 1, fptr) != 1)
rc
和1
被交换。你打算写rc
字节,第二个参数是每个单位的大小,第三个是单位数。既没有与t_filesize
有任何关系。
while (rc >= 0)
不足,您还需要一个计数器来接收已接收的总字节数。在rc
的循环增量中,如果total >= t_filesize
中断。
rc = ssh_scp_read(scp, buffer, sizeof(buffer));
延展到
rc = ssh_scp_read(scp, buffer, min(sizeof(buffer), t_filesize - total));
因此,您不要求读取不可用的字节。
至于为什么你的文件太小,这是因为你遇到了首先提到的错误的错误处理。您只获得第一个缓冲区已满(因为缓冲区未完全使用,分别不是这样),并且您已经从传输中返回。