創建基於MailKit和MimeKit的.NET基礎郵件服務
郵件服務是一般的系統都會擁有和需要的功能，但是對於.NET項目來說，郵件服務的創建和使用會較為的麻煩。.NET對於郵件功能提供了System.Net.Mail用於創建郵件服務，該基礎服務提供郵件的基礎操作，並且使用也較為的簡單。對於真正將該功能使用於項目的人，就會慢慢發現其中的優缺點，甚至有些時候不能忍受其中的問題。在這裏介紹一種微軟用於替代System.Net.Mail的郵件服務組件MailKit和MimeKit，官網地址：http://www.mimekit.net/。GitHub地址：https://github.com/jstedfast/MimeKit。下面就具體的介紹一下。
一.MailKit和MimeKit基礎概述：
MailKit組件的支持的客戶端類型比較多，例如SMTP客戶端、POP3客戶端、IMAP4客戶端。該組件是一個跨平臺的Email組件，該組件支持.NET 4.0，.NET 4.5，Xamarin.Android，Xamarin.iOS，Windows Phone 8.1等等平臺。
MimeKit提供了一個MIME解析器，組件具備的解析特性靈活、性能高、很好的處理各種各樣的破碎的MIME格式化。MimeKit的性能實際上與GMime相當。
該組件在安全性的還是比較高的，處理安全的方式較多，SASL認證、支持S / MIME v3.2、支持OpenPGP、支持DKIM簽名等等方式。Mailkit組件可以通過CancellationToken取消對應的操作，CancellationToken傳播應取消操作的通知，一個的CancellationToken使線程，線程池工作項目之間，或取消合作任務的對象。過實例化CancellationTokenSource對象來創建取消令牌，該對象管理從其CancellationTokenSource.Token屬性檢索的取消令牌。然後，將取消令牌傳遞到應該收到取消通知的任意數量的線程，任務或操作。令牌不能用於啟動取消。
MailKit組件支持異步操作，在內部編寫的有關I/O異步操作的類。
二.創建基礎郵件服務：
介紹過MailKit和MimeKit組建的基礎信息，接下來就介紹一下如何使用兩個組件的基本功能，在這裏我將基本操作做了一個簡單的封裝，一般的項目可以直接引用封裝好的類，大家可以根據實際的情況對該組件進行擴展。
1.郵件發送基礎服務API
/// <summary>
/// 郵件服務API
/// </summary>
public static class MailServiceApi
{
/// <summary>
/// 發送郵件
/// </summary>
/// <param name="mailBodyEntity">郵件基礎信息</param>
/// <param name="sendServerConfiguration">發件人基礎信息</param>
public static SendResultEntity SendMail(MailBodyEntity mailBodyEntity,
SendServerConfigurationEntity sendServerConfiguration)
{
if (sendServerConfiguration == null)
{
throw new ArgumentNullException();
}
if (sendServerConfiguration == null)
{
throw new ArgumentNullException();
}
var sendResultEntity = new SendResultEntity();
using (var client = new SmtpClient(new ProtocolLogger(CreateMailLog())))
{
client.ServerCertificateValidationCallback = (s, c, h, e) => true;
Connection(mailBodyEntity, sendServerConfiguration, client, sendResultEntity);
if (sendResultEntity.ResultStatus == false)
{
return sendResultEntity;
}
SmtpClientBaseMessage(client);
Authenticate(mailBodyEntity, sendServerConfiguration, client, sendResultEntity);
if (sendResultEntity.ResultStatus == false)
{
return sendResultEntity;
}
Send(mailBodyEntity, sendServerConfiguration, client, sendResultEntity);
if (sendResultEntity.ResultStatus == false)
{
return sendResultEntity;
}
client.Disconnect(true);
}
return sendResultEntity;
}
/// <summary>
/// 連接服務器
/// </summary>
/// <param name="mailBodyEntity">郵件內容</param>
/// <param name="sendServerConfiguration">發送配置</param>
/// <param name="client">客戶端對象</param>
/// <param name="sendResultEntity">發送結果</param>
public static void Connection(MailBodyEntity mailBodyEntity, SendServerConfigurationEntity sendServerConfiguration,
SmtpClient client, SendResultEntity sendResultEntity)
{
try
{
client.Connect(sendServerConfiguration.SmtpHost, sendServerConfiguration.SmtpPort);
}
catch (SmtpCommandException ex)
{
sendResultEntity.ResultInformation = $"嘗試連接時出錯:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
catch (SmtpProtocolException ex)
{
sendResultEntity.ResultInformation = $"嘗試連接時的協議錯誤:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
catch (Exception ex)
{
sendResultEntity.ResultInformation = $"服務器連接錯誤:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
}
/// <summary>
/// 賬戶認證
/// </summary>
/// <param name="mailBodyEntity">郵件內容</param>
/// <param name="sendServerConfiguration">發送配置</param>
/// <param name="client">客戶端對象</param>
/// <param name="sendResultEntity">發送結果</param>
public static void Authenticate(MailBodyEntity mailBodyEntity, SendServerConfigurationEntity sendServerConfiguration,
SmtpClient client, SendResultEntity sendResultEntity)
{
try
{
client.Authenticate(sendServerConfiguration.SenderAccount, sendServerConfiguration.SenderPassword);
}
catch (AuthenticationException ex)
{
sendResultEntity.ResultInformation = $"無效的用戶名或密碼:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
catch (SmtpCommandException ex)
{
sendResultEntity.ResultInformation = $"嘗試驗證錯誤:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
catch (SmtpProtocolException ex)
{
sendResultEntity.ResultInformation = $"嘗試驗證時的協議錯誤:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
catch (Exception ex)
{
sendResultEntity.ResultInformation = $"賬戶認證錯誤:{0}" + ex.Message;
sendResultEntity.ResultStatus = false;
}
}
/// <summary>
/// 發送郵件
/// </summary>
/// <param name="mailBodyEntity">郵件內容</param>
/// <param name="sendServerConfiguration">發送配置</param>
/// <param name="client">客戶端對象</param>
/// <param name="sendResultEntity">發送結果</param>
public static void Send(MailBodyEntity mailBodyEntity, SendServerConfigurationEntity sendServerConfiguration,
SmtpClient client, SendResultEntity sendResultEntity)
{
try
{
client.Send(MailMessage.AssemblyMailMessage(mailBodyEntity));
}
catch (SmtpCommandException ex)
{
switch (ex.ErrorCode)
{
case SmtpErrorCode.RecipientNotAccepted:
sendResultEntity.ResultInformation = $"收件人未被接受:{ex.Message}";
break;
case SmtpErrorCode.SenderNotAccepted:
sendResultEntity.ResultInformation = $"發件人未被接受:{ex.Message}";
break;
case SmtpErrorCode.MessageNotAccepted:
sendResultEntity.ResultInformation = $"消息未被接受:{ex.Message}";
break;
}
sendResultEntity.ResultStatus = false;
}
catch (SmtpProtocolException ex)
{
sendResultEntity.ResultInformation = $"發送消息時的協議錯誤:{ex.Message}";
sendResultEntity.ResultStatus = false;
}
catch (Exception ex)
{
sendResultEntity.ResultInformation = $"郵件接收失敗:{ex.Message}";
sendResultEntity.ResultStatus = false;
}
}
/// <summary>
/// 獲取SMTP基礎信息
/// </summary>
/// <param name="client">客戶端對象</param>
/// <returns></returns>
public static MailServerInformation SmtpClientBaseMessage(SmtpClient client)
{
var mailServerInformation = new MailServerInformation
{
Authentication = client.Capabilities.HasFlag(SmtpCapabilities.Authentication),
BinaryMime = client.Capabilities.HasFlag(SmtpCapabilities.BinaryMime),
Dsn = client.Capabilities.HasFlag(SmtpCapabilities.Dsn),
EightBitMime = client.Capabilities.HasFlag(SmtpCapabilities.EightBitMime),
Size = client.MaxSize
};
return mailServerInformation;
}
/// <summary>
/// 創建郵件日誌文件
/// </summary>
/// <returns></returns>
public static string CreateMailLog()
{
var logPath = AppDomain.CurrentDomain.BaseDirectory + "/DocumentLog/" +
Guid.NewGuid() + ".txt";
if (File.Exists(logPath)) return logPath;
var fs = File.Create(logPath);
fs.Close();
return logPath;
}
}
2.組裝郵件消息：
/// <summary>
/// 郵件信息
/// </summary>
public static class MailMessage
{
/// <summary>
/// 組裝郵件文本/附件郵件信息
/// </summary>
/// <param name="mailBodyEntity">郵件消息實體</param>
/// <returns></returns>
public static MimeMessage AssemblyMailMessage(MailBodyEntity mailBodyEntity)
{
if (mailBodyEntity == null)
{
throw new ArgumentNullException(nameof(mailBodyEntity));
}
var message = new MimeMessage();
//設置郵件基本信息
SetMailBaseMessage(message, mailBodyEntity);
var multipart = new Multipart("mixed");
//插入文本消息
if (string.IsNullOrEmpty(mailBodyEntity.MailTextBody) == false)
{
var alternative = new MultipartAlternative
{
AssemblyMailTextMessage(mailBodyEntity.MailTextBody, mailBodyEntity.MailBodyType)
};
multipart.Add(alternative);
}
//插入附件
if (mailBodyEntity.MailFilePath != null && File.Exists(mailBodyEntity.MailFilePath) == false)
{
var mimePart = AssemblyMailAttachmentMessage(mailBodyEntity.MailFileType, mailBodyEntity.MailFileSubType,
mailBodyEntity.MailFilePath);
multipart.Add(mimePart);
}
//組合郵件內容
message.Body = multipart;
return message;
}
/// <summary>
/// 設置郵件基礎信息
/// </summary>
/// <param name="minMessag"></param>
/// <param name="mailBodyEntity"></param>
/// <returns></returns>
public static MimeMessage SetMailBaseMessage(MimeMessage minMessag, MailBodyEntity mailBodyEntity)
{
if (minMessag == null)
{
throw new ArgumentNullException();
}
if (mailBodyEntity == null)
{
throw new ArgumentNullException();
}
//插入發件人
minMessag.From.Add(new MailboxAddress(mailBodyEntity.Sender, mailBodyEntity.SenderAddress));
//插入收件人
foreach (var recipients in mailBodyEntity.Recipients)
{
minMessag.To.Add(new MailboxAddress(recipients));
}
//插入抄送人
foreach (var cC in mailBodyEntity.Cc)
{
minMessag.Cc.Add(new MailboxAddress(cC));
}
//插入主題
minMessag.Subject = mailBodyEntity.Subject;
return minMessag;
}
/// <summary>
/// 組裝郵件文本信息
/// </summary>
/// <param name="mailBody">郵件文本內容</param>
/// <param name="textPartType">郵件文本類型(plain,html,rtf,xml)</param>
/// <returns></returns>
public static TextPart AssemblyMailTextMessage(string mailBody, string textPartType)
{
if (string.IsNullOrEmpty(mailBody))
{
throw new ArgumentNullException();
}
if (string.IsNullOrEmpty(textPartType))
{
throw new ArgumentNullException();
}
var textBody = new TextPart(textPartType)
{
Text = mailBody
};
return textBody;
}
/// <summary>
/// 組裝郵件附件信息
/// </summary>
/// <param name="fileAttachmentType">附件類型(image,application)</param>
/// <param name="fileAttachmentSubType">附件子類型 </param>
/// <param name="fileAttachmentPath">附件路徑</param>
/// <returns></returns>
public static MimePart AssemblyMailAttachmentMessage(string fileAttachmentType, string fileAttachmentSubType, string fileAttachmentPath)
{
if (string.IsNullOrEmpty(fileAttachmentSubType))
{
throw new ArgumentNullException();
}
if (string.IsNullOrEmpty(fileAttachmentType))
{
throw new ArgumentNullException();
}
if (string.IsNullOrEmpty(fileAttachmentPath))
{
throw new ArgumentNullException();
}
var attachment = new MimePart(fileAttachmentType, fileAttachmentSubType)
{
Content = new MimeContent(File.OpenRead(fileAttachmentPath)),
ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
ContentTransferEncoding = ContentEncoding.Base64,
FileName = Path.GetFileName(fileAttachmentPath)
};
return attachment;
}
}
3.郵件基礎服務實體：
/// <summary>
/// 郵件內容實體
/// </summary>
public class MailBodyEntity
{
/// <summary>
/// 郵件文本內容
/// </summary>
public string MailTextBody { get; set; }
/// <summary>
/// 郵件內容類型
/// </summary>
public string MailBodyType { get; set; }
/// <summary>
/// 郵件附件文件類型
/// </summary>
public string MailFileType { get; set; }
/// <summary>
/// 郵件附件文件子類型
/// </summary>
public string MailFileSubType { get; set; }
/// <summary>
/// 郵件附件文件路徑
/// </summary>
public string MailFilePath { get; set; }
/// <summary>
/// 收件人
/// </summary>
public List<string> Recipients { get; set; }
/// <summary>
/// 抄送
/// </summary>
public List<string> Cc { get; set; }
/// <summary>
/// 發件人
/// </summary>
public string Sender { get; set; }
/// <summary>
/// 發件人地址
/// </summary>
public string SenderAddress { get; set; }
/// <summary>
/// 郵件主題
/// </summary>
public string Subject { get; set; }
/// <summary>
/// 郵件內容
/// </summary>
public string Body { get; set; }
}
/// <summary>
/// 郵件服務器基礎信息
/// </summary>
public class MailServerInformation
{
/// <summary>
/// SMTP服務器支持SASL機制類型
/// </summary>
public bool Authentication { get; set; }
/// <summary>
/// SMTP服務器對消息的大小
/// </summary>
public uint Size { get; set; }
/// <summary>
/// SMTP服務器支持傳遞狀態通知
/// </summary>
public bool Dsn { get; set; }
/// <summary>
/// SMTP服務器支持Content-Transfer-Encoding
/// </summary>
public bool EightBitMime { get; set; }
/// <summary>
/// SMTP服務器支持Content-Transfer-Encoding
/// </summary>
public bool BinaryMime { get; set; }
/// <summary>
/// SMTP服務器在消息頭中支持UTF-8
/// </summary>
public string UTF8 { get; set; }
}
/// <summary>
/// 郵件發送結果
/// </summary>
public class SendResultEntity
{
/// <summary>
/// 結果信息
/// </summary>
public string ResultInformation { get; set; } = "發送成功！";
/// <summary>
/// 結果狀態
/// </summary>
public bool ResultStatus { get; set; } = true;
}
/// <summary>
/// 郵件發送服務器配置
/// </summary>
public class SendServerConfigurationEntity
{
/// <summary>
/// 郵箱SMTP服務器地址
/// </summary>
public string SmtpHost { get; set; }
/// <summary>
/// 郵箱SMTP服務器端口
/// </summary>
public int SmtpPort { get; set; }
/// <summary>
/// 是否啟用IsSsl
/// </summary>
public bool IsSsl { get; set; }
/// <summary>
/// 郵件編碼
/// </summary>
public string MailEncoding { get; set; }
/// <summary>
/// 發件人賬號
/// </summary>
public string SenderAccount { get; set; }
/// <summary>
/// 發件人密碼
/// </summary>
public string SenderPassword { get; set; }
}
上面提供了借助MailKit組建創建發送郵件服務，分別是創建郵件服務器連接，組裝郵件基礎信息，郵件基礎實體。發送郵件的基礎服務比較的多，下面介紹一下郵件的接收。
/// <summary>
/// 跟投郵件服務API
/// </summary>
public static class ReceiveEmailServiceApi
{
/// <summary>
/// 設置發件人信息
/// </summary>
/// <returns></returns>
public static SendServerConfigurationEntity SetSendMessage()
{
var sendServerConfiguration = new SendServerConfigurationEntity
{
SmtpHost = ConfigurationManager.AppSettings["SmtpServer"],
SmtpPort = int.Parse(ConfigurationManager.AppSettings["SmtpPort"]),
IsSsl = Convert.ToBoolean(ConfigurationManager.AppSettings["IsSsl"]),
MailEncoding = ConfigurationManager.AppSettings["MailEncoding"],
SenderAccount = ConfigurationManager.AppSettings["SenderAccount"],
SenderPassword = ConfigurationManager.AppSettings["SenderPassword"]
};
return sendServerConfiguration;
}
/// <summary>
/// 接收郵件
/// </summary>
public static void ReceiveEmail()
{
var sendServerConfiguration = SetSendMessage();
if (sendServerConfiguration == null)
{
throw new ArgumentNullException();
}
using (var client = new ImapClient(new ProtocolLogger(CreateMailLog())))
{
client.Connect(sendServerConfiguration.SmtpHost, sendServerConfiguration.SmtpPort,
SecureSocketOptions.SslOnConnect);
client.Authenticate(sendServerConfiguration.SenderAccount, sendServerConfiguration.SenderPassword);
client.Inbox.Open(FolderAccess.ReadOnly);
var uids = client.Inbox.Search(SearchQuery.All);
foreach (var uid in uids)
{
var message = client.Inbox.GetMessage(uid);
message.WriteTo($"{uid}.eml");
}
client.Disconnect(true);
}
}
/// <summary>
/// 下載郵件內容
/// </summary>
public static void DownloadBodyParts()
{
var sendServerConfiguration = SetSendMessage();
using (var client = new ImapClient())
{
client.Connect(sendServerConfiguration.SmtpHost, sendServerConfiguration.SmtpPort,
SecureSocketOptions.SslOnConnect);
client.Authenticate(sendServerConfiguration.SenderAccount, sendServerConfiguration.SenderPassword);
client.Inbox.Open(FolderAccess.ReadOnly);
// 搜索Subject標題包含“MimeKit”或“MailKit”的郵件
var query = SearchQuery.SubjectContains("MimeKit").Or(SearchQuery.SubjectContains("MailKit"));
var uids = client.Inbox.Search(query);
// 獲取搜索結果的摘要信息（我們需要UID和BODYSTRUCTURE每條消息，以便我們可以提取文本正文和附件）
var items = client.Inbox.Fetch(uids, MessageSummaryItems.UniqueId | MessageSummaryItems.BodyStructure);
foreach (var item in items)
{
// 確定一個目錄來保存內容
var directory = Path.Combine(AppDomain.CurrentDomain.BaseDirectory + "/MailBody", item.UniqueId.ToString());
Directory.CreateDirectory(directory);
// IMessageSummary.TextBody是一個便利的屬性，可以為我們找到“文本/純文本”的正文部分
var bodyPart = item.TextBody;
// 下載‘text / plain‘正文部分
var body = (TextPart) client.Inbox.GetBodyPart(item.UniqueId, bodyPart);
// TextPart.Text是一個便利的屬性，它解碼內容並將結果轉換為我們的字符串
var text = body.Text;
File.WriteAllText(Path.Combine(directory, "body.txt"), text);
// 現在遍歷所有附件並將其保存到磁盤
foreach (var attachment in item.Attachments)
{
// 像我們對內容所做的那樣下載附件
var entity = client.Inbox.GetBodyPart(item.UniqueId, attachment);
// 附件可以是message / rfc822部件或常規MIME部件
var messagePart = entity as MessagePart;
if (messagePart != null)
{
var rfc822 = messagePart;
var path = Path.Combine(directory, attachment.PartSpecifier + ".eml");
rfc822.Message.WriteTo(path);
}
else
{
var part = (MimePart) entity;
// 註意：這可能是空的，但大多數會指定一個文件名
var fileName = part.FileName;
var path = Path.Combine(directory, fileName);
// decode and save the content to a file
using (var stream = File.Create(path))
part.Content.DecodeTo(stream);
}
}
}
client.Disconnect(true);
}
}
/// <summary>
/// 創建郵件日誌文件
/// </summary>
/// <returns></returns>
public static string CreateMailLog()
{
var logPath = AppDomain.CurrentDomain.BaseDirectory + "/DocumentLog/" +
DateTime.Now.ToUniversalTime().ToString(CultureInfo.InvariantCulture) + ".txt";
if (File.Exists(logPath)) return logPath;
var fs = File.Create(logPath);
fs.Close();
return logPath;
}
}
面只是簡單的介紹了郵件的接收，如果需要更加深入的了解功能，可以進一步對組件源碼進行解析，該組件的文檔為較為的豐富。
三.組件使用感悟：
MailKit和MimeKit組件在項目的使用中較為的便捷，基本包含了所有的基礎郵件服務操作。組件提供的SmtpClient類提供的功能很豐富，例如連接郵件服務器，郵件賬戶認證，組裝郵件消息，獲取郵件服務器配置信息等等方法的提供，可以讓我們在項目中快速的獲取郵件服務的所有信息。
使用過郵件功能的項目 都會有困擾，客戶端與郵件服務器的連接是否成功，以及郵件是否發送成功狀態沒有辦法很快的獲取，只能根據郵件服務器返回的一場狀態進行判斷。但是MailKit提供對應的方法和異常類，對郵件服務器返回的異常信息進行解析，客戶端可以根據這些異常類獲取郵件狀態。
MailKit組件的提供了ProtocolLogger類，該類用於記錄SMTP操作基礎信息，該類作用為記錄郵件服務日誌。在郵件發送完畢後，需要及時的關閉連接，調用Disconnect(true)方法。
原文：https://www.cnblogs.com/pengze0902/p/8519715.html
創建基於MailKit和MimeKit的.NET基礎郵件服務