c# - LibCurlNet 支持 SMTP 协议吗？

Question

我正在开发一个发送电子邮件的应用程序。我开始使用 libcurlnet 库，这是我目前得到的代码：

Curl.GlobalInit((int)CURLinitFlag.CURL_GLOBAL_ALL);
Easy easyHandle=new Easy();
easyHandle.SetOpt(CURLoption.CURLOPT_URL, "smtp.gmail.com");

根据这个例子（smtp-mail），我可以使用 CURLOPT_MAIL_FROM 和 CURLOPT_MAIL_RCPT。像这样：

easyHandle.SetOpt(CURLoption.CURLOPT_MAIL_FROM, "abcd@gmail.com");

但它不起作用。它不包含 CURLOPT_MAIL_FROM 的定义。有人使用 C# 和 LibCurlNet 库吗？请帮帮我。

Answer 1

我想你会发现使用MailKit比使用 LibCurlNet 简单得多。nuget.org 上也有 NuGet 包：http ://www.nuget.org/packages/MailKit/

Answer 2

您可以使用CurlSharp。CurlSharp 是 LibCurlNet 的继任者。它被积极维护并支持最新的 libcurl 版本。

CurlSharp中的 SMTP 客户端：

using System;
using System.Runtime.InteropServices;
using CurlSharp;

namespace SmtpMail
{
    [StructLayout(LayoutKind.Sequential)]
    internal struct UploadContext
    {
        public int LinesRead;
    }

    internal class SmtpMail
    {
        private static void Main(string[] args)
        {
            try
            {
                Curl.GlobalInit(CurlInitFlag.All);

                using (var curl = new CurlEasy())
                {
                    curl.Url = "smtp://localhost:25";
                    curl.Upload = true;

                    curl.ReadFunction = PayloadSource;
                    curl.ReadData = new UploadContext();
                    curl.SetOpt(CurlOption.MailFrom, "<from@example.com>");
                    using (var recipients = new CurlSlist())
                    {
                        recipients.Append("<to@example.net>");
                        recipients.Append("<cc@example.org>");
                        var s = recipients.Strings;
                        curl.SetOpt(CurlOption.MailRcpt, recipients.Handle);

                        curl.Perform();
                    }
                }

                Curl.GlobalCleanup();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }
        }

        private static byte[] GetBytes(string str)
        {
            var bytes = new byte[str.Length*sizeof (char)];
            Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
            return bytes;
        }

        private static int PayloadSource(byte[] buf, int size, int nmemb, object extradata)
        {
            var payloadText = new[]
                              {
                                  "Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n",
                                  "To: <to@example.net>\r\n",
                                  "From: <from@example.org> (Example User)\r\n",
                                  "Cc: <cc@example.org> (Another example User)\r\n",
                                  "Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@rfcpedant.example.org>\r\n",
                                  "Subject: SMTP example message\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"
                              };

            var ctxUpload = (UploadContext) extradata;

            if ((ctxUpload.LinesRead >= 0) &&
                (ctxUpload.LinesRead < payloadText.Length) &&
                (size != 0) && (nmemb != 0) &&
                ((size*nmemb) > 0))
            {
                var line = payloadText[ctxUpload.LinesRead++];
                var lineBuf = GetBytes(line);
                Buffer.BlockCopy(lineBuf, 0, buf, 0, lineBuf.Length);
                return lineBuf.Length;
            }
            return 0;
        }
    }
}