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qt5集成libcurl实现tftp和ftp的方法之二:实现tftp文件上传和下载

时间:2016-07-19 13:50:21      阅读:310      评论:0      收藏:0      [点我收藏+]

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QT5本身对ftp和tftp的支持不太好,找了很多地方也没找到好用的方法,无奈之下只好使用开源的curl来实现。但是该怎么使用tftp一直没找到说明。在curl的doc下有一堆的examples,但是就是没有tftp的,但是文档里明明说实现了tftp啊?答案是人家感觉tftp太简单了,都懒得单独写个demo了,╮(╯▽╰)╭深深的被鄙视了。下面我就说一下该怎么使用tftp功能。

1.建立tftp测试环境

写代码过程中随时会出问题,一旦环境出了问题,一切都是白搭,所以首先建立tftp的测试环境,方法非常简单。为了减少意外,最好使用两台电脑(或者电脑+虚拟机,总之尽量隔离开),每个电脑安装一个tftpd程序,window自带该功能的,但是太麻烦,下载一个tftpd32.exe就行了。
打开其中一台电脑的tftp32.exe程序,选择“tftp server”端,当做服务器。然后在另一个电脑打开tftp32.exe之后选择“client(客户端)”选项,如下图所示:
技术分享
注意这里的设置:
1.“current directory”是tftp的工作目录,该目录下的文件可以直接tftp传输,下载的文件也自动放在这里。
2.“server interface”是本机IP地址,这个要注意网卡和网段,选错的话会导致传输连接无法建立。
3.Host:服务器的IP地址,Port:端口,tftp默认都是69
4.LocalFile:本地文件,例如“ds.txt”。Remote File:服务器端文件名,例如“2.2”。注意这里的设置,如果是下载的话(Get模式),就是将服务器端的”2.2“文件保存到本地,名称为ds.txt。如果是上传的话(Put模式),就是将本地文件”ds.txt“上传到服务器,名称为”2.2“。如果重复操作,文件会被覆盖,因此这里要注意。
传输完成,会出现下面的界面:
技术分享

2.curl实现文件下载

好了,上面测试成功的话,就可以用curl写代码了。过程就不细说了,直接上代码:
/*upload*/
#define LOCAL_FILE      "D:/tmp/curl.c"

#define REMOTE_URL      "tftp://192.168.1.110:69/uploading.txt"


static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
  curl_off_t nread;
  /* in real-world cases, this would probably get this data differently
     as this fread() stuff is exactly what the library already would do
     by default internally */
  size_t retcode = fread(ptr, size, nmemb, (FILE*)stream);

  nread = (curl_off_t)retcode;

  fprintf(stderr, "*** We read %" CURL_FORMAT_CURL_OFF_T
          " bytes from file\n", nread);
  return retcode;
}
int tftpfileUpload()
{
       CURL *curl;
      CURLcode res;
      FILE *hd_src;
      struct stat file_info;
      curl_off_t fsize;

      struct curl_slist *headerlist=NULL;


      /* get the file size of the local file */
      if(stat(LOCAL_FILE, &file_info)) {
        printf("Couldnt open '%s': %s\n", LOCAL_FILE, strerror(errno));
        return 1;
      }
      fsize = (curl_off_t)file_info.st_size;

      printf("Local file size: %" CURL_FORMAT_CURL_OFF_T " bytes.\n", fsize);

      /* get a FILE * of the same file */
      hd_src = fopen(LOCAL_FILE, "rb");

      /* In windows, this will init the winsock stuff */
      curl_global_init(CURL_GLOBAL_ALL);

      /* get a curl handle */
      curl = curl_easy_init();
      if(curl) {

        /* we want to use our own read function */
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);

        /* enable uploading */
        curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

        /* specify target */
        curl_easy_setopt(curl,CURLOPT_URL, REMOTE_URL);

        /* pass in that last of FTP commands to run after the transfer */
        curl_easy_setopt(curl, CURLOPT_POSTQUOTE, headerlist);

        /* now specify which file to upload */
        curl_easy_setopt(curl, CURLOPT_READDATA, hd_src);


        curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE,
                         (curl_off_t)fsize);

        /* Now run off and do what you've been told! */
        res = curl_easy_perform(curl);
        /* Check for errors */
        if(res != CURLE_OK)
          fprintf(stderr, "curl_easy_perform() failed: %s\n",
                  curl_easy_strerror(res));

        /* clean up the FTP commands list */
        curl_slist_free_all (headerlist);

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

      curl_global_cleanup();
      return 0;
    }
外部调用方法:
 downloadFileFromServer();
执行的时候就可以发现程序将服务器端下的“tftps.cpp”保存到本地了。

3.实现文件上传

还是直接上代码;
/*upload*/
#define LOCAL_FILE      "D:/tmp/curl.c"
#define UPLOAD_FILE_AS  "uploading.txt"
#define REMOTE_URL      "tftp://192.168.1.110:69/uploading.txt"
#define RENAME_FILE_TO  "renamed.txt"

static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
  curl_off_t nread;
  /* in real-world cases, this would probably get this data differently
     as this fread() stuff is exactly what the library already would do
     by default internally */
  size_t retcode = fread(ptr, size, nmemb, (FILE*)stream);

  nread = (curl_off_t)retcode;

  fprintf(stderr, "*** We read %" CURL_FORMAT_CURL_OFF_T
          " bytes from file\n", nread);
  return retcode;
}
int tftpfileUpload()
{
       CURL *curl;
      CURLcode res;
      FILE *hd_src;
      struct stat file_info;
      curl_off_t fsize;

      struct curl_slist *headerlist=NULL;
      static const char buf_1 [] =  UPLOAD_FILE_AS;
      static const char buf_2 [] =  RENAME_FILE_TO;

      /* get the file size of the local file */
      if(stat(LOCAL_FILE, &file_info)) {
        printf("Couldnt open '%s': %s\n", LOCAL_FILE, strerror(errno));
        return 1;
      }
      fsize = (curl_off_t)file_info.st_size;

      printf("Local file size: %" CURL_FORMAT_CURL_OFF_T " bytes.\n", fsize);

      /* get a FILE * of the same file */
      hd_src = fopen(LOCAL_FILE, "rb");

      /* In windows, this will init the winsock stuff */
      curl_global_init(CURL_GLOBAL_ALL);

      /* get a curl handle */
      curl = curl_easy_init();
      if(curl) {
 

        /* we want to use our own read function */
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);

        /* enable uploading */
        curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

        /* specify target */
        curl_easy_setopt(curl,CURLOPT_URL, REMOTE_URL);

        /* pass in that last of FTP commands to run after the transfer */
        curl_easy_setopt(curl, CURLOPT_POSTQUOTE, headerlist);

        /* now specify which file to upload */
        curl_easy_setopt(curl, CURLOPT_READDATA, hd_src);

        /* Set the size of the file to upload (optional).  If you give a *_LARGE
           option you MUST make sure that the type of the passed-in argument is a
           curl_off_t. If you use CURLOPT_INFILESIZE (without _LARGE) you must
           make sure that to pass in a type 'long' argument. */
        curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE,
                         (curl_off_t)fsize);

        /* Now run off and do what you've been told! */
        res = curl_easy_perform(curl);
        /* Check for errors */
        if(res != CURLE_OK)
          fprintf(stderr, "curl_easy_perform() failed: %s\n",
                  curl_easy_strerror(res));

        /* clean up the FTP commands list */
        curl_slist_free_all (headerlist);

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

      curl_global_cleanup();
      return 0;
    }
调用方法为
tftpfileUpload();
OK !就这么简单。


qt5集成libcurl实现tftp和ftp的方法之二:实现tftp文件上传和下载

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原文地址:http://blog.csdn.net/xueyushenzhou/article/details/51952961

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