cURL 终端命令成功执行，而 libcurl 程序没有答案

【问题标题】：cURL terminal command executes successfully while libcurl program doesn'tcURL 终端命令成功执行，而 libcurl 程序没有
【发布时间】：2017-04-17 10:23:44
【问题描述】：

#include <curl/curl.h>

int main(int argc, char *argv[])
{
  CURLcode ret;
  CURL *hnd;
  struct curl_slist *slist1;

  slist1 = NULL;
  slist1 = curl_slist_append(slist1, "reciever@gmail.com");

  hnd = curl_easy_init();
  curl_easy_setopt(hnd, CURLOPT_INFILESIZE_LARGE, (curl_off_t)179);
  curl_easy_setopt(hnd, CURLOPT_URL, "smtps://smtp.gmail.com:465/mail.txt");
  curl_easy_setopt(hnd, CURLOPT_UPLOAD, 1L);
  curl_easy_setopt(hnd, CURLOPT_USERPWD, "sender@gmail.com:senderPass");
  curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curl/7.47.0");
  curl_easy_setopt(hnd, CURLOPT_MAXREDIRS, 50L);
  curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYPEER, 0L);
  curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYHOST, 0L);
  curl_easy_setopt(hnd, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
  curl_easy_setopt(hnd, CURLOPT_TCP_KEEPALIVE, 1L);
  curl_easy_setopt(hnd, CURLOPT_MAIL_FROM, "sender@gmail.com");
  curl_easy_setopt(hnd, CURLOPT_MAIL_RCPT, slist1);
  curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);

  ret = curl_easy_perform(hnd);

  curl_easy_cleanup(hnd);
  hnd = NULL;
  curl_slist_free_all(slist1);
  slist1 = NULL;

  return (int)ret;
}

上面的 libcurl 代码是通过命令行使用以下命令生成的：

curl --url 'smtps://smtp.gmail.com:465' --ssl-reqd --mail-from 'sender@gmail.com' --mail-rcpt 'receiver@gmail.com' --upload-file mail.txt --user 'sender@gmail.com:senderPass' --insecure --libcurl -myCode.c

命令时

curl --url 'smtps://smtp.gmail.com:465' --ssl-reqd --mail-from 'sender@gmail.com' --mail-rcpt 'receiver@gmail.com' --upload-file mail.txt --user 'sender@gmail.com:senderPass' --insecure

成功发送邮件，为什么myCode.c发送邮件失败？详细选项的输出在之后停止响应

< 354 Go ahead [somecharacters].43 -gsmtp

mail.txt 文件是：

From: "I am Sender" <sender@gmail.com>
To: "I am Receiver" <receiver@gmail.com>
Subject: This is a test

Hi,
I’m sending this mail with curl through my gmail account.
Bye!

【问题讨论】：

标签： c curl gmail libcurl smtps

【解决方案1】：

您必须使用CURLOPT_READDATA 指定要读取的文件的文件描述符：

curl_easy_setopt(hnd, CURLOPT_READDATA, fd);

整个代码如下所示：

#include <curl/curl.h>

int main(int argc, char *argv[])
{
    CURLcode ret;
    CURL *hnd;
    struct curl_slist *slist1;

    slist1 = NULL;
    slist1 = curl_slist_append(slist1, "reciever@gmail.com");

    FILE *fd;

    fd = fopen("mail.txt", "rb");

    if(!fd)
        return 1; 

    hnd = curl_easy_init();
    curl_easy_setopt(hnd, CURLOPT_INFILESIZE_LARGE, (curl_off_t)179);
    curl_easy_setopt(hnd, CURLOPT_URL, "smtps://smtp.gmail.com:465/mail.txt");
    curl_easy_setopt(hnd, CURLOPT_UPLOAD, 1L);

    curl_easy_setopt(hnd, CURLOPT_READDATA, fd); 

    curl_easy_setopt(hnd, CURLOPT_USERPWD, "sender@gmail.com:senderPass");
    curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curl/7.47.0");
    curl_easy_setopt(hnd, CURLOPT_MAXREDIRS, 50L);
    curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYPEER, 0L);
    curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYHOST, 0L);
    curl_easy_setopt(hnd, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
    curl_easy_setopt(hnd, CURLOPT_TCP_KEEPALIVE, 1L);
    curl_easy_setopt(hnd, CURLOPT_MAIL_FROM, "sender@gmail.com");
    curl_easy_setopt(hnd, CURLOPT_MAIL_RCPT, slist1);
    curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);

    ret = curl_easy_perform(hnd);

    curl_easy_cleanup(hnd);
    hnd = NULL;
    curl_slist_free_all(slist1);
    slist1 = NULL;

    return (int)ret;
}

【讨论】：