深入Lumisoft.NET组件与.NET API实现邮件发送功能的对比分析

我在另一篇文章《深入lumisoft.net实现邮件发送功能的方法详解》有大致对这个lumisoft.net组件的使用进行了介绍，当然lumisoft.net组件除了提供邮件发送功能外，还提供了邮件接收等功能的处理（包括基于pop3协议和imap协议），而.net则除了提供smtp协议功能外，则没有提供pop3协议处理的相关类库，因此收取邮件这需要自己进行封装（需要也可以参考codeproject.com上的相关文章）。

1、.net的邮件发送功能实现
.net本身封装了一个smtpclient类以及相关的邮件对象类，这样利用这些类库，也可以方便实现邮件的发送功能的了。

如添加发送人地址，抄送地址，以及暗送地址（多个地址用逗号分开）代码如下。

string toemails = mailinfo.toemail;

            string bcc = "";
            mailinfo.recipientbcc.foreach(obj => bcc += string.format("{0},", obj));
            bcc = bcc.trim(',');

            string cc = "";
            mailinfo.recipientcc.foreach(obj => cc += string.format("{0},", obj));
            cc = cc.trim(',');

            mailmessage mail = new mailmessage(settinginfo.mailfrom, toemails);
            if (!string.isnullorempty(bcc))
            {
                mail.bcc.add(bcc);
            }
            if (!string.isnullorempty(cc))
            {
                mail.cc.add(cc);
            }

.net的附件和嵌入式资源由对象attachment和linkedresource进行管理，他们的利用代码如下所示：

//附件
            foreach (string filename in mailinfo.attachments)
            {
                mail.attachments.add(new attachment(filename));
            }

            //嵌入资源
            alternateview view = alternateview.createalternateviewfromstring(mailinfo.body, encoding.utf8, mediatypenames.text.html);
            foreach (linkedattachementinfo link in mailinfo.embedobjects)
            {
                linkedresource resource = new linkedresource(link.stream, link.mimetype);
                resource.contentid = link.contentid;
                view.linkedresources.add(resource);
            }
            mail.alternateviews.add(view);

发送邮件的其他部分代码如下所示

mail.isbodyhtml = mailinfo.isbodyhtml;
            mail.bodyencoding = encoding.utf8;
            mail.subject = mailinfo.subject;
            mail.subjectencoding = encoding.utf8;

            //发送账户设置信息
            smtpclient client = new smtpclient();
            client.host = settinginfo.smtpserver;
            client.port = settinginfo.smptport;
            client.usedefaultcredentials = false;
            client.deliverymethod = smtpdeliverymethod.network;
            client.credentials = new networkcredential(settinginfo.smtpuser, settinginfo.smtppass);

            bool success = false;
            try
            {
                client.send(mail);
                success = true;
            }
            catch (exception ex)
            {
                logtexthelper.error(ex);
                //throw;
            }

上面利用.net的smtpclient发送邮件操作的完整代码如下:

/// <summary>
        /// 发送外部邮件（系统配置，系统邮件）
        /// </summary>
        /// <param name="mailinfo">发送邮件信息</param>
        /// <returns></returns>
        public commonresult send(mailinfo mailinfo)
        {
            commonresult result = new commonresult();
            try
            {
                appconfig config = new appconfig();
                string maildomain = config.appconfigget("maildomain");
                string mailusername = config.appconfigget("mailusername");
                string mailpassword = config.appconfigget("mailpassword");
                string mailport = config.appconfigget("mailport");
                string mailfrom = config.appconfigget("mailfrom");
                int port = 25;
                int.tryparse(mailport, out port);

                smtpsettinginfo settinginfo = new smtpsettinginfo(maildomain, port,
                    mailusername, mailpassword, mailfrom);

                result.success = privatesendemail(mailinfo, settinginfo);
            }
            catch (exception ex)
            {
                result.errormessage = ex.message;
                throw;
            }

            return result;
        }

        /// <summary>
        /// 通用发送邮件操作
        /// </summary>
        private static bool privatesendemail(mailinfo mailinfo, smtpsettinginfo settinginfo)
        {         
            string toemails = mailinfo.toemail;

            string bcc = "";
            mailinfo.recipientbcc.foreach(obj => bcc += string.format("{0},", obj));
            bcc = bcc.trim(',');

            string cc = "";
            mailinfo.recipientcc.foreach(obj => cc += string.format("{0},", obj));
            cc = cc.trim(',');

            mailmessage mail = new mailmessage(settinginfo.mailfrom, toemails);
            if (!string.isnullorempty(bcc))
            {
                mail.bcc.add(bcc);
            }
            if (!string.isnullorempty(cc))
            {
                mail.cc.add(cc);
            }

            //附件
            foreach (string filename in mailinfo.attachments)
            {
                mail.attachments.add(new attachment(filename));
            }

            //嵌入资源
            alternateview view = alternateview.createalternateviewfromstring(mailinfo.body, encoding.utf8, mediatypenames.text.html);
            foreach (linkedattachementinfo link in mailinfo.embedobjects)
            {
                linkedresource resource = new linkedresource(link.stream, link.mimetype);
                resource.contentid = link.contentid;
                view.linkedresources.add(resource);
            }
            mail.alternateviews.add(view);
            mail.isbodyhtml = mailinfo.isbodyhtml;
            mail.bodyencoding = encoding.utf8;
            mail.subject = mailinfo.subject;
            mail.subjectencoding = encoding.utf8;

            //发送账户设置信息
            smtpclient client = new smtpclient();
            client.host = settinginfo.smtpserver;
            client.port = settinginfo.smptport;
            client.usedefaultcredentials = false;
            client.deliverymethod = smtpdeliverymethod.network;
            client.credentials = new networkcredential(settinginfo.smtpuser, settinginfo.smtppass);

            bool success = false;
            try
            {
                client.send(mail);
                success = true;
            }
            catch (exception ex)
            {
                logtexthelper.error(ex);
                //throw;
            }

            string message = string.format("发送给【{0}】的邮件“{1}”，{2}，时间：{3}",
                mailinfo.toemail[0], mailinfo.subject, success ? "发送成功" : "发送失败", datetime.now);
            logtexthelper.info(message);

            return success;
        }

2、基于lumisoft.net组件的邮件发送功能实现

基于lumisoft.net组件的邮件发送，也是一种很常用的，因为这个开源组件非常强大，经常可以在一些程序中被使用。

这个发送邮件的功能主要是利用smtp_client类来实现的，如下代码所示。注意其中的authenticate函数已经被舍弃，可以使用auth方法进行验证。但是函数参数有所不同，根据验证对象，使用不同的验证方式，一般选择auth_sasl_client_plain对象即可。

public bool send()
        {
            bool sended = false;
            using (smtp_client client = new smtp_client())
            {
                client.connect(smtpserver, smtpport, smtpusessl);
                client.ehlohelo(smtpserver);
                var authhh = new auth_sasl_client_plain(username, password);
                client.auth(authhh);
                //client.authenticate(username, password);
                //string text = client.greetingtext;
                client.mailfrom(from, -1);
                foreach (string address in tolist.keys)
                {
                    client.rcptto(address);
                }

                //采用mail_message类型的stream
                mail_message m = create_plaintext_html_attachment_image(tolist, cclist, from, fromdisplay, subject, body, attachments);
                using (memorystream stream = new memorystream())
                {
                    m.tostream(stream, new mime_encoding_encodedword(mime_encodedwordencoding.q, encoding.utf8), encoding.utf8);
                    stream.position = 0;
                    client.sendmessage(stream);

                    sended = true;
                }
                if (m != null)
                {
                    m.dispose();
                }

                client.disconnect();
            }
            return sended;
        }

构造用于smtp发送的数据，可以使用mail_message 对象，也可以使用mime对象，虽然读都可以实现发送功能，不过mime对象是舍弃的对象了。

构造mail_message对象后，创建用于发送的格式要转换为stream对象。转换为发送的stream操作如下所示。

using (memorystream stream = new memorystream())
{
        m.tostream(stream, new mime_encoding_encodedword(mime_encodedwordencoding.q, encoding.utf8), encoding.utf8);
        stream.position = 0;
        client.sendmessage(stream);

        sended = true;
 }

构造mail_message格式的邮件操作如下所示。

private mail_message create_plaintext_html_attachment_image(dictionary<string,string> tomails, dictionary<string, string> ccmails, string mailfrom, string mailfromdisplay,
            string subject, string body, dictionary<string, string> attachments, string notifyemail = "", string plainttexttips = "")
        {
            mail_message msg = new mail_message();
            msg.mimeversion = "1.0";
            msg.messageid = mime_utils.createmessageid();
            msg.date = datetime.now;
            msg.subject = subject;
            msg.from = new mail_t_mailboxlist();
            msg.from.add(new mail_t_mailbox(mailfromdisplay, mailfrom));
            msg.to = new mail_t_addresslist();
            foreach (string address in tomails.keys)
            {
                string displayname = tomails[address];
                msg.to.add(new mail_t_mailbox(displayname, address));
            }
            msg.cc = new mail_t_addresslist();
            foreach (string address in ccmails.keys)
            {
                string displayname = ccmails[address];
                msg.cc.add(new mail_t_mailbox(displayname, address));
            }           

            //设置回执通知
            if (!string.isnullorempty(notifyemail) && validateutil.isemail(notifyemail))
            {
                msg.dispositionnotificationto.add(new mail_t_mailbox(notifyemail, notifyemail));
            }

            #region myregion

            //--- multipart/mixed -----------------------------------
            mime_h_contenttype contenttype_multipartmixed = new mime_h_contenttype(mime_mediatypes.multipart.mixed);
            contenttype_multipartmixed.param_boundary = guid.newguid().tostring().replace('-', '.');
            mime_b_multipartmixed multipartmixed = new mime_b_multipartmixed(contenttype_multipartmixed);
            msg.body = multipartmixed;

            //--- multipart/alternative -----------------------------
            mime_entity entity_multipartalternative = new mime_entity();
            mime_h_contenttype contenttype_multipartalternative = new mime_h_contenttype(mime_mediatypes.multipart.alternative);
            contenttype_multipartalternative.param_boundary = guid.newguid().tostring().replace('-', '.');
            mime_b_multipartalternative multipartalternative = new mime_b_multipartalternative(contenttype_multipartalternative);
            entity_multipartalternative.body = multipartalternative;
            multipartmixed.bodyparts.add(entity_multipartalternative);

            //--- text/plain ----------------------------------------
            mime_entity entity_text_plain = new mime_entity();
            mime_b_text text_plain = new mime_b_text(mime_mediatypes.text.plain);
            entity_text_plain.body = text_plain;

            //普通文本邮件内容，如果对方的收件客户端不支持html，这是必需的
            string plaintextbody = "如果你邮件客户端不支持html格式，或者你切换到“普通文本”视图，将看到此内容";
            if (!string.isnullorempty(plainttexttips))
            {
                plaintextbody = plainttexttips;
            }

            text_plain.settext(mime_transferencodings.quotedprintable, encoding.utf8, plaintextbody);
            multipartalternative.bodyparts.add(entity_text_plain);

            //--- text/html -----------------------------------------
            string htmltext = body;//"<html>这是一份测试邮件，<img src=\"cid:test.jpg\">来自<font color=red><b>lumisoft.net</b></font></html>";
            mime_entity entity_text_html = new mime_entity();
            mime_b_text text_html = new mime_b_text(mime_mediatypes.text.html);
            entity_text_html.body = text_html;
            text_html.settext(mime_transferencodings.quotedprintable, encoding.utf8, htmltext);
            multipartalternative.bodyparts.add(entity_text_html);

            //--- application/octet-stream -------------------------
            webclient client = new webclient();
            foreach (string attach in attachments.keys)
            {
                try
                {
                    byte[] bytes = client.downloaddata(attach);
                    using (memorystream stream = new memorystream(bytes))
                    {
                        multipartmixed.bodyparts.add(mail_message.createattachment(stream, attachments[attach]));
                    }
                }
                catch (exception ex)
                {
                    logtexthelper.error(ex);
                }
            }

            #endregion

            return msg;
        }

而构造mime格式的操作如下所示。

private mime create_html_attachment_image(string mailto, string mailfrom, string mailfromdisplay,
            string subject, string body, list<string> attachments, dictionary<string, string> embedimages, string notifyemail = "", string plainttexttips = "",
            string replyemail = "")
        {
            mime m = new mime();
            mimeentity mainentity = m.mainentity;

            mainentity.from = new addresslist();
            mainentity.from.add(new mailboxaddress(mailfromdisplay, mailfrom));
            mainentity.to = new addresslist();
            mainentity.to.add(new mailboxaddress(mailto, mailto));
            mainentity.subject = subject;
            mainentity.contenttype = mediatype_enum.multipart_mixed;

            //设置回执通知
            if (!string.isnullorempty(notifyemail) && validateutil.isemail(notifyemail))
            {
                mainentity.dsn = notifyemail;
            }

            //设置统一回复地址
            if (!string.isnullorempty(replyemail) && validateutil.isemail(replyemail))
            {
                mainentity.replyto = new addresslist();
                mainentity.replyto.add(new mailboxaddress(replyemail, replyemail));
            }

            mimeentity textentity = mainentity.childentities.add();
            textentity.contenttype = mediatype_enum.text_html;
            textentity.contenttransferencoding = contenttransferencoding_enum.quotedprintable;
            textentity.datatext = body;

            //附件
            foreach (string attach in attachments)
            {
                mimeentity attachmententity = mainentity.childentities.add();
                attachmententity.contenttype = mediatype_enum.application_octet_stream;
                attachmententity.contentdisposition = contentdisposition_enum.attachment;
                attachmententity.contenttransferencoding = contenttransferencoding_enum.base64;
                fileinfo file = new fileinfo(attach);
                attachmententity.contentdisposition_filename = file.name;
                attachmententity.datafromfile(attach);
            }

            //嵌入图片
            foreach (string key in embedimages.keys)
            {
                mimeentity attachmententity = mainentity.childentities.add();
                attachmententity.contenttype = mediatype_enum.application_octet_stream;
                attachmententity.contentdisposition = contentdisposition_enum.inline;
                attachmententity.contenttransferencoding = contenttransferencoding_enum.base64;
                string imagefile = embedimages[key];
                fileinfo file = new fileinfo(imagefile);
                attachmententity.contentdisposition_filename = file.name;

                //string displayname = path.getfilenamewithoutextension(filename);
                attachmententity.contentid = key;//bytestools.bytestohex(encoding.default.getbytes(filename));

                attachmententity.datafromfile(imagefile);
            }

            return m;
        }

综合以上两者的发送功能，都可以实现邮件的发送操作，如下界面是发送邮件界面。

3、lumisoft.net存储eml邮件文件以及发送eml文件操作

除了上面的发送普通邮件，lumisoft还支持吧邮件序列号存储到文件(.eml邮件文件)里面，然后也可以通过把文件读取到流里面，进行发送，对于某种场合，可以把邮件存储到eml文件是一个很好的操作。

存储eml文件的相关操作如下所示。

private void btncreatefile_click(object sender, eventargs e)
        {
            string attachfile = path.combine(application.startuppath, "attachment/hotel2.png");
            list<string> attachments = new list<string>();
            attachments.add(attachfile);
            string subject = "测试邮件";
            string body = "<html>这是一份测试邮件，来自<font color=red><b>lumisoft.net</b></font></html>";
            string bodyembedy = "<html>这是一份测试邮件<img src=\"cid:test.jpg\">，来自<font color=red><b>lumisoft.net</b></font></html>";
            dictionary<string, string> embedlist = new dictionary<string, string>();
            embedlist.add("test.jpg", "c:\\test.jpg");

            //存储为eml文件
            string path = path.combine(application.startuppath, "eml");
            directoryutil.assertdirexist(path);
            string emlfile = string.format("{0}/{1}.eml", path, datetime.now.tofiletime());

            mime m = create_html_attachment_image(to, from, from, subject, bodyembedy, attachments, embedlist);
            m.tofile(emlfile);

            messageutil.showtips("ok");
        }

发送eml文件操作如下所示。

private void btnsendfile_click(object sender, eventargs e)
        {
            using (smtp_client client = new smtp_client())
            {
                int smtpport = smtpusessl ? wellknownports.smtp_ssl : wellknownports.smtp;

                client.connect(smtpserver, smtpport, smtpusessl);
                client.ehlohelo(smtpserver);
                //var authhh = new auth_sasl_client_plain(username, password);
                //client.auth(authhh);
                client.authenticate(username, password);
                //string text = client.greetingtext;
                client.mailfrom(from, -1);
                client.rcptto(to);

                string path = path.combine(application.startuppath, "eml");
                string emlfile = directory.getfiles(path)[0];
                var msg = mail_message.parsefromfile(emlfile);

                memorystream stream = new memorystream();
                msg.tostream(stream, new mime_encoding_encodedword(mime_encodedwordencoding.q, encoding.utf8), encoding.utf8);
                stream.position = 0;
                client.sendmessage(stream);
                client.disconnect();
            }
            messageutil.showtips("ok");
        }