c++ - 为什么我收到 curl 错误 55：尝试发送电子邮件时向对等方发送数据失败？

Question

我使用此处提供的此模板使用 curl 向自己发送电子邮件：https ://www.phidgets.com/?view=articles&article=LIBCURLHowTo

在 Linux 中一切正常；但是，我试图让它在 Windows 中工作，我收到了这个控制台消息：

curl_easy_perform() failed: Failed sending data to the peer

Process returned 55 (0x37)   execution time : 0.165 s
Press any key to continue.

我的完整代码如下：

/*
 * SMTP example showing how to send e-mails
 *
 */
#include <stdio.h>
#include <string.h>
#include <curl\curl.h>
#include <fstream>
#include <Windows.h>

/* This is a simple example showing how to send mail using libcurl's SMTP
 * capabilities. For an example of using the multi interface please see
 * smtp-multi.c.
 *
 * Note that this example requires libcurl 7.20.0 or above.
 */

#define FROM    "[e-mail]"
#define TO      "[e-mail]"

static const char *payload_text[] = {
  "Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n",
  "To: " TO "(Steve)\r\n",
  "From: " FROM "(Me)\r\n",
  "Subject: hacked_system.txt has been deleted!\r\n",
  "\r\n", /* empty line to divide headers from body, see RFC5322 */
  "hacked_system.txt has been deleted from SteveOS!\r\n",
  NULL
};

struct upload_status {
  int lines_read;
};

static size_t payload_source(void *ptr, size_t size, size_t nmemb, void *userp)
{
  struct upload_status *upload_ctx = (struct upload_status *)userp;
  const char *data;

  if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
    return 0;
  }

  data = payload_text[upload_ctx->lines_read];

  if(data) {
    size_t len = strlen(data);
    memcpy(ptr, data, len);
    upload_ctx->lines_read++;

    return len;
  }

  return 0;
}

int main(void)

{

   {mkdir("C:\\SteveOS");
   std::ofstream outfile ("C:\\SteveOS\\hacked_system.txt");
   DeleteFile  ("C:\\SteveOS\\hacked_system.txt");}

  CURL *curl;
  CURLcode res = CURLE_OK;
  struct curl_slist *recipients = NULL;
  struct upload_status upload_ctx;

  upload_ctx.lines_read = 0;

  curl = curl_easy_init();
  if(curl) {
    /* This is the URL for your mailserver */
    curl_easy_setopt(curl, CURLOPT_URL, "smtp://smtp.gmail.com:587");

    /* Note that this option isn't strictly required, omitting it will result
     * in libcurl sending the MAIL FROM command with empty sender data. All
     * autoresponses should have an empty reverse-path, and should be directed
     * to the address in the reverse-path which triggered them. Otherwise,
     * they could cause an endless loop. See RFC 5321 Section 4.5.5 for more
     * details.
     */
    curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM);

    /* Add two recipients, in this particular case they correspond to the
     * To: and Cc: addressees in the header, but they could be any kind of
     * recipient. */
    recipients = curl_slist_append(recipients, TO);
    curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);

    /* We're using a callback function to specify the payload (the headers and
     * body of the message). You could just use the CURLOPT_READDATA option to
     * specify a FILE pointer to read from. */
    curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
    curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

    curl_easy_setopt(curl, CURLOPT_USERNAME, "[e-mail]");
    curl_easy_setopt(curl, CURLOPT_PASSWORD, "xxxxxxxxxxxxxxxxxx");

    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);

    /* Send the message */
    res = curl_easy_perform(curl);

    /* Check for errors */
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));

    /* Free the list of recipients */
    curl_slist_free_all(recipients);

    /* curl won't send the QUIT command until you call cleanup, so you should
     * be able to re-use this connection for additional messages (setting
     * CURLOPT_MAIL_FROM and CURLOPT_MAIL_RCPT as required, and calling
     * curl_easy_perform() again. It may not be a good idea to keep the
     * connection open for a very long time though (more than a few minutes
     * may result in the server timing out the connection), and you do want to
     * clean up in the end.
     */
    curl_easy_cleanup(curl);
  }

  return (int)res;
}

电子邮件以这种方式阅读的原因是因为这是一项课堂作业。此外，我的任务是创建 hacked_system.txt 文件并将其删除。但是，该文件没有被删除，所以现在我的问题是双重的。我将如何删除文件？

在 Linux 上运行的代码有两个电子邮件地址，一个 to: 和一个 cc:。我已经删除了 cc:，但我还没有在 Linux 上测试过。为了发送电子邮件，我使用了我的真实电子邮件地址，发件人：和收件人：。此外，密码是我已用 x 替换的 Google 帐户应用程序密码。

代替 DeleteFile，我在 Linux 上使用了 Boost 库，但事实证明为 Windows 构建库并不值得。

我将不胜感激任何帮助。谢谢你。

编辑：可能是因为我没有将 SSL 集成到 libcurl 中吗？

标签： c++emailcurl