如何使用OpenPop保存电子邮件附件

Question

我创建了一个Web邮件应用程序，如何查看和保存附件？

我正在使用第三方dll OpenPop，可以发送带附件的邮件和读取没有附件的邮件。

这个可以正常工作：

Pop3Client pop3Client = (Pop3Client)Session["Pop3Client"]; // Creating newPopClient 
int messageNumber = int.Parse(Request.QueryString["MessageNumber"]);
Message message = pop3Client.GetMessage(messageNumber);
MessagePart messagePart = message.MessagePart.MessageParts[1];
lblFrom.Text = message.Headers.From.Address; // Writeing message. 
lblSubject.Text = message.Headers.Subject;
lblBody.Text=messagePart.BodyEncoding.GetString(messagePart.Body);

这段代码的第二部分显示了附件的内容，但仅在其为文本文件时有用。我需要能够保存附件。此外，我在这里拥有的底部代码部分会覆盖我的消息正文，因此如果我收到附件，则无法查看我的消息正文。

if (messagePart.IsAttachment == true) { 
    foreach (MessagePart attachment in message.FindAllAttachments()) { 
        if (attachment.FileName.Equals("blabla.pdf")) { // Save the raw bytes to a file
            File.WriteAllBytes(attachment.FileName, attachment.Body); //overwrites MessagePart.Body with attachment 
        } 
    } 
}

- Pomster

Answer 1

如果还有人在寻找答案，这对我很有效。

var client = new Pop3Client();
try
{            
    client.Connect("MailServerName", Port_Number, UseSSL); //UseSSL true or false
    client.Authenticate("UserID", "password");   

    var messageCount = client.GetMessageCount();
    var Messages = new List<Message>(messageCount);

    for (int i = 0;i < messageCount; i++)
    {
        Message getMessage = client.GetMessage(i + 1);
        Messages.Add(getMessage);
    }

    foreach (Message msg in Messages)
    {
        foreach (var attachment in msg.FindAllAttachments())
        {
            string filePath = Path.Combine(@"C:\Attachment", attachment.FileName);
            if(attachment.FileName.Equals("blabla.pdf"))
            {
                FileStream Stream = new FileStream(filePath, FileMode.Create);
                BinaryWriter BinaryStream = new BinaryWriter(Stream);
                BinaryStream.Write(attachment.Body);
                BinaryStream.Close();
            }
        }
    }
}
catch (Exception ex)
{
    Console.WriteLine("", ex.Message);
}
finally
{
    if (client.Connected)
        client.Dispose();
}

- ElectricRouge

---

这段代码将UTF-8附件中的重音字符替换为两个问号。如何解决？我在http://stackoverflow.com/questions/27949470/how-to-read-utf-8-mail-attachmets-from-pop3上发布了这个单独的问题。 - Andrus

谢谢 - Mange tak - Gracie - Perfecto :-) - JanBorup

Answer 2

对于未来的读者，使用更新版本的Pop3更容易。

using( OpenPop.Pop3.Pop3Client client = new Pop3Client())
        {
            client.Connect("in.mail.Your.Mailserver.com", 110, false);
            client.Authenticate("usernamePop3", "passwordPop3", AuthenticationMethod.UsernameAndPassword);
            if (client.Connected)
            {
                int messageCount = client.GetMessageCount();
                List<Message> allMessages = new List<Message>(messageCount);
                for (int i = messageCount; i > 0; i--)
                {
                    allMessages.Add(client.GetMessage(i));
                }
                foreach (Message msg in allMessages)
                {
                    var att = msg.FindAllAttachments();
                    foreach (var ado in att)
                    {
                        ado.Save(new System.IO.FileInfo(System.IO.Path.Combine("c:\\xlsx", ado.FileName)));
                    }
                }
            }
           }

- adopilot

Answer 3

OpenPop.Mime.Message 类有一个 ToMailMessage() 方法，可以将 OpenPop 的 Message 转换为 System.Net.Mail.MailMessage，该类具有一个 Attachments 属性。尝试从中提取附件。

- Stanislav Berkov

---

我已经尝试过这个方法，但它并没有起作用。OpenPop将整个消息都视为附件，但我猜这种做法也算是正确的，所以你可以得到我的赏金。既然你是唯一的回答者，而且最终也会得到赏金，那我就把它给你了。 - Pomster

Answer 4

我写了这篇文章很长时间了，但是请看一下我用于保存位于POP服务器上的电子邮件消息中的XML附件的代码块：

OpenPOP.POP3.POPClient client = new POPClient("pop.yourserver.co.uk", 110, "[e-mail]", "password_goes_here", AuthenticationMethod.USERPASS); 
if (client.Connected) {
int msgCount = client.GetMessageCount();

/* Cycle through messages */
for (int x = 0; x < msgCount; x++)
    {
        OpenPOP.MIMEParser.Message msg = client.GetMessage(x, false);
        if (msg != null) {
            for (int y = 0; y < msg.AttachmentCount; y++)
            {
                Attachment attachment = (Attachment)msg.Attachments[y];

                if (string.Compare(attachment.ContentType, "text/xml") == 0)
                {
                    System.Xml.XmlDocument doc = new System.Xml.XmlDocument();

                    string xml = attachment.DecodeAsText();
                    doc.LoadXml(xml);
                    doc.Save(@"C:\POP3Temp\test.xml");
                }
            }
        }
    }
}

- Karl

---

另外，请参考www.codeproject.com/Answers/181619/How-i-can-extract-attachment-file-from-MessageRaw#answer1和http://codingrage.blogspot.com/2008/04/fetching-and-processing-pop3-email-in.html。 - as9876

是的 @AYS，那是我的博客。 :) - Karl

Answer 5

    private KeyValuePair<byte[], FileInfo> parse(MessagePart part)
    {
        var _steam = new MemoryStream();
        part.Save(_steam);
        //...
        var _info = new FileInfo(part.FileName);
        return new KeyValuePair<byte[], FileInfo>(_steam.ToArray(), _info);
    }

    //... How to use
    var _attachments = message 
        .FindAllAttachments()
        .Select(a => parse(a))
    ;

- Bruno Jares

Answer 6

 List<Message> lstMessages = FetchAllMessages("pop.mail-server.com", 995, true,"Your Email ID", "Your Password");

以上代码行使用相应的pop邮件服务器获取您电子邮件中所有消息的列表。

例如，要获取列表中最新（或第一个）电子邮件的附件，可以编写以下代码。

 List<MessagePart> lstAttachments = lstMessages[0].FindAllAttachments();  //Gets all the attachments associated with latest (or first) email from the list.
 for (int attachment = 0; attachment < lstAttachments.Count; attachment++)
 {
         FileInfo file = new FileInfo("Some File Name");
         lstAttachments[attachment].Save(file);
 } 

- VAMSHI PAIDIMARRI

Answer 7

如果有人需要VB.NET的代码：

For Each emailAttachment In client.GetMessage(count).FindAllAttachments
    AttachmentName = emailAttachment.FileName
    '----// Write the file to the folder in the following format: <UniqueID> followed by two underscores followed by the <AttachmentName>
    Dim strmFile As New FileStream(Path.Combine("C:\Test\Attachments", EmailUniqueID & "__" & AttachmentName), FileMode.Create)
    Dim BinaryStream = New BinaryWriter(strmFile)
    BinaryStream.Write(emailAttachment.Body)
    BinaryStream.Close()
Next

- Dieter Stalmann