將字符串添加到文件緩沖區，以便cURL smtp的消息正文發送電子郵件

Question

我正在嘗試修改工作的cURL電子郵件發送示例以添加消息正文 。 我不確定為什么我發現的所有帶有附件的curl電子郵件示例都沒有消息正文。

我需要發送帶有PDF文件附件的短文本電子郵件。

到目前為止，這是我嘗試過的方法，未注釋行，但可以編譯並運行，但無法發送。 我知道消息正文應與主題之間用一個“ \\ r \\ n”（空行）分隔，但這不是正確的方法。

//Create structure of email to be sent
    fileBuf = new char[ADD_SIZE + no_of_rows][CHARS];  //ADD_SIZE for TO,FROM,SUBJECT,CONTENT-TYPE,CONTENT-TRANSFER-
                                                       //ENCODING,CONETNT-DISPOSITION and \r\n
    strcpy(fileBuf[len++],"To: " TO "\r\n");
    buffer_size += strlen(fileBuf[len-1]);
    strcpy(fileBuf[len++],"From: " FROM "\r\n");
    buffer_size += strlen(fileBuf[len-1]);
    strcpy(fileBuf[len++],"Subject: SMTP TLS example message\r\n");
    buffer_size += strlen(fileBuf[len-1]);

    //strcpy(fileBuf[len++],"\r\n");
    //buffer_size += strlen(fileBuf[len-1]);
    //strcpy(fileBuf[len++],"Message goes here, hopefully...\r\n");
    //buffer_size += strlen(fileBuf[len-1]);

    strcpy(fileBuf[len++],"Content-Type: application/x-msdownload; name=\"" FILENAME "\"\r\n");
    buffer_size += strlen(fileBuf[len-1]);
    strcpy(fileBuf[len++],"Content-Transfer-Encoding: base64\r\n");
    buffer_size += strlen(fileBuf[len-1]);
    strcpy(fileBuf[len++],"Content-Disposition: attachment; filename=\"" FILENAME "\"\r\n");
    buffer_size += strlen(fileBuf[len-1]);
    strcpy(fileBuf[len++],"\r\n");
    buffer_size += strlen(fileBuf[len-1]);

完整的項目代碼在這里，請參閱解決方案7。

任何有關如何完成此操作的建議將不勝感激。

[edit]使用非常簡單的cURL進行測試，產生了0字節的附件：

#define FILENAME  "Rpt05162017.pdf"
static const char *payload_text[] = {
  "To: " TO "\r\n",
  "From: " FROM "(Example User)\r\n",
  //"Cc: " CC "(Another example User)\r\n",
  "Subject: SMTPS Example\r\n",
  "Date: 17-May-2017\r\n",
  "User-Agent: My eMail Client\r\n",
  "MIME-Version: 1.0\r\n",
  "Content-Type: multipart/mixed;\r\n",
   " boundary=\"------------030203080101020302070708\"\r\n",
  "\r\nThis is a multi-part message in MIME format.\r\n",
  "--------------030203080101020302070708\r\n",
  "Content-Type: text/plain; charset=utf-8; format=flowed\r\n",
  "Content-Transfer-Encoding: 7bit\r\n",
  "\r\n", // empty line to divide headers from body, see RFC5322
  "The body of the message starts here.\r\n",
  "\r\n",
  "It could be a lot of lines, could be MIME encoded, whatever.\r\n",
  "Check RFC5322.\r\n\r\n",
  "--------------030203080101020302070708\r\n",
  "Content-Type: application/x-msdownload; name=\"" FILENAME "\"\r\n",
  "Content-Transfer-Encoding: base64\r\n",
  "Content-Disposition: attachment; filename=\"" FILENAME "\"\r\n",
  "\r\n--------------030203080101020302070708--",
  NULL
};

Answer 1

不清楚如何發送所有這些東西。 您創建了2D字符串數組，並將其插入每個標頭。 它們都有填充字節，它們會破壞您的消息。

嘗試簡化它？

std:string header =
"To: " TO "\r\n"
"From: " FROM "\r\n"
"Subject: SMTP TLS example message\r\n"
"Content-Type: application/x-msdownload; name=\"" FILENAME "\"\r\n"
"Content-Transfer-Encoding: base64\r\n"
"Content-Disposition: attachment; filename=\"" FILENAME "\"\r\n"
"\r\n";

然后簡單地發送郵件header隨后body您的留言。

---

使用更新的payload_text ，發送零文件的附件並不奇怪，因為您發送的是空文件。 發送payload_text您必須發送文件正文，然后在正文之后附加多部分結束后綴：

"\r\n--------------030203080101020302070708--"