curl ftp libcurl 功能使用

最新推荐文章于 2024-10-28 11:14:02 发布

转载最新推荐文章于 2024-10-28 11:14:02 发布 · 727 阅读

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#curl #ftp

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本文介绍了一个使用CURL库从FTP服务器下载文件到本地的C++代码示例。通过定义一个自定义的fwrite回调函数，该程序能够将远程FTP服务器上的文件流写入到本地磁盘上指定的文件中。程序首先初始化CURL，设置URL为FTP服务器上的目标文件，然后定义了my_fwrite函数用于接收和写入数据，最后执行curl_easy_perform进行文件下载。

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struct FtpFile {
  const char *filename;
  FILE *stream;
};

static size_t my_fwrite(void *buffer, size_t size, size_t nmemb, void *stream)
{
  struct FtpFile *out = (struct FtpFile *)stream;
  if(out && !out->stream) {
    /* open file for writing */
    out->stream = fopen(out->filename, "wb");
    if(!out->stream)
      return -1; /* failure, can't open file to write */
  }
  return fwrite(buffer, size, nmemb, out->stream);
}

void fileLoadFtp()
{
  CURL *curl;
  CURLcode res;

  QString locale = ui->lineEdit_path->text();
  char *file = locale.toLatin1().data();
  QFileInfo fileInfo(locale);
  QString fileName = fileInfo.fileName();
  QString remote = "ftp://user:password@ftp.example.com/" + fileName;
  char *remote_url = remote.toLatin1().data(); //服务器路径

  struct FtpFile ftpfile = {
    file, /* name to store the file as if successful */
    NULL
  };

  curl_global_init(CURL_GLOBAL_DEFAULT);

  curl = curl_easy_init();
  if(curl) {
    /*
     * You better replace the URL with one that works!
     */
    curl_easy_setopt(curl, CURLOPT_URL, remote_url);
    /* Define our callback to get called when there's data to be written */
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite);
    /* Set a pointer to our struct to pass to the callback */
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile);

    curl_easy_setopt(curl, CURLOPT_SSH_AUTH_TYPES, CURLSSH_AUTH_PASSWORD);

    /* Switch on full protocol/debug output */
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);

    res = curl_easy_perform(curl);

    /* always cleanup */
    curl_easy_cleanup(curl);

    if(CURLE_OK != res) {
      /* we failed */
      fprintf(stderr, "curl told us %d\n", res);
    }
  }

  if(ftpfile.stream)
    fclose(ftpfile.stream); /* close the local file */

  curl_global_cleanup();
}