c++ - 使用 Libcurl 从 FTP 服务器文件下载多个文件

Question

我使用以下代码从 FTP 服务器下载所有文件

接下来的步骤是: 1.创建文件的FTP列表

    getFTPList(string sHost, string sUser, string sPass, string sUri)
{
  CURL *curl;
  CURLcode res;
  FILE *ftplister;
  string host = "ftp://";
  host += sHost;
  host += "/sample/";
  string furl = host + sUri;  
  string usrpwd = sUser;
  usrpwd += ":";
  usrpwd += sPass;
  /* local file name to store the file as */ 
  ftplister = fopen("ftp-list", "wb"); /* b is binary, needed on win32 */   
  curl = curl_easy_init();
  if(curl) {
    /* Get a file listing from sunet */ 
    curl_easy_setopt(curl, CURLOPT_URL, furl.c_str() );
    curl_easy_setopt(curl, CURLOPT_USERPWD, usrpwd.c_str());
    curl_easy_setopt(curl, CURLOPT_FTPLISTONLY, TRUE);
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &write_list);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, ftplister);
    res = curl_easy_perform(curl);
    /* Check for errors */ 
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));

    /* always cleanup */ 
    curl_easy_cleanup(curl);
  } 
  fclose(ftplister); /* close the local file */   
}

1. 使用这个列表下载文件，递归调用下载函数

   int main(){
   FILE *ftpfile; 
   string line;
   ftpfile = fopen("ftp-list", "r"); 
   ifstream infile("ftp-list");
    while ( getline(infile, line) )
    {
       string url, ofname, surl = "ftp://myhost/uploader/", sfname = "C:\\CNAP\\";        
       url = surl + line;
       ofname = sfname +line;
       cout<<url<<"   "<<ofname<<endl;
       char* theVal ;
       char* theStr ;
       theVal = new char [url.size()+1];
       theStr = new char [ofname.size()+1];
       strcpy(theVal, url.c_str());
       strcpy(theStr, ofname.c_str());       
       downloadFile(theVal, theStr);
    }
   return 0;
   }
   

现在下载功能:

size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
    size_t written;
    written = fwrite(ptr, size, nmemb, stream);
    return written;
   }

   void downloadFile(const char* url, const char* ofname)
   {
    CURL *curl;
        FILE *fp;
        CURLcode res;        
        curl = curl_easy_init();
        if (curl){
            fp = fopen(ofname,"wb");
            curl_easy_setopt(curl, CURLOPT_URL, url);
            curl_easy_setopt(curl, CURLOPT_USERPWD, "user:pass");
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
            res = curl_easy_perform(curl);
            curl_easy_cleanup(curl);
            fclose(fp);
        }
     }

它在实现时效果很好，但只能下载文本文件或一些带有文本的文件，如果我下载图像或 docx 或 zip 或 rar 或任何非文本文件，它会失败，无法打开下载后(说文件无效)。

我不确定我错过了什么，我们将不胜感激。

我知道这是一种低效的编码方式，但我只需要正确下载(任何文件)。提高效率是我的下一个议程。

PS: 这里使用了这个方法 Downloading multiple files with libcurl in C++

谢谢

Answer 1

下载时的文件需要以二进制文件打开

fp = fopen(ofname,"wb");

谢谢罗伯的帮助