Reading Email using Pop3 in C#

Question

I am looking for a method of reading emails using Pop3 in C# 2.0. Currently, I am using code found in CodeProject. However, this solution is less than ideal. The biggest problem is that it doesn't support emails written in unicode.

Solution 1

I've successfully used OpenPop.NET to access emails via POP3.

Solution 2

downloading the email via the POP3 protocol is the easy part of the task. The protocol is quite simple and the only hard part could be advanced authentication methods if you don't want to send a clear text password over the network (and cannot use the SSL encrypted communication channel). See RFC 1939: Post Office Protocol - Version 3 and RFC 1734: POP3 AUTHentication command for details.

The hard part comes when you have to parse the received email, which means parsing MIME format in most cases. You can write quick&dirty MIME parser in a few hours or days and it will handle 95+% of all incoming messages. Improving the parser so it can parse almost any email means:

• getting email samples sent from the most popular mail clients and improve the parser in order to fix errors and RFC misinterpretations generated by them.
• Making sure that messages violating RFC for message headers and content will not crash your parser and that you will be able to read every readable or guessable value from the mangled email
• correct handling of internationalization issues (e.g. languages written from righ to left, correct encoding for specific language etc)
• UNICODE
• Attachments and hierarchical message item tree as seen in "Mime torture email sample"
• S/MIME (signed and encrypted emails).
• and so on

Debugging a robust MIME parser takes months of work. I know, because I was watching my friend writing one such parser for the component mentioned below and was writing a few unit tests for it too ;-)

Back to the original question.

Following code taken from our POP3 Tutorial page and links would help you:

// 
// create client, connect and log in 
Pop3 client = new Pop3();
client.Connect("pop3.example.org");
client.Login("username", "password");

// get message list 
Pop3MessageCollection list = client.GetMessageList();

if (list.Count == 0)
{
    Console.WriteLine("There are no messages in the mailbox.");
}
else 
{
    // download the first message 
    MailMessage message = client.GetMailMessage(list[0].SequenceNumber);
    ...
}

client.Disconnect();

• HOWTO: Download emails from a GMail account in C# (blogpost)
• Rebex Mail for .NET (POP3/IMAP client component for .NET)
• Rebex Secure Mail for .NET (POP3/IMAP client component for .NET - SSL enabled)

Solution 3

My open source application BugTracker.NET includes a POP3 client that can parse MIME. Both the POP3 code and the MIME code are from other authors, but you can see how it all fits together in my app.

For the MIME parsing, I use http://anmar.eu.org/projects/sharpmimetools/.

See the file POP3Main.cs, POP3Client.cs, and insert_bug.aspx

Solution 4

You can also try Mail.dll mail component, it has SSL support, unicode, and multi-national email support:

using(Pop3 pop3 = new Pop3())
{
    pop3.Connect("mail.host.com");           // Connect to server and login
    pop3.Login("user", "password");

    foreach(string uid in pop3.GetAll())
    {
        IMail email = new MailBuilder()
            .CreateFromEml(pop3.GetMessageByUID(uid));
          Console.WriteLine( email.Subject );
    }
    pop3.Close(false);      
}

You can download it here at https://www.limilabs.com/mail

Please note that this is a commercial product I've created.

Solution 5

I wouldn't recommend OpenPOP. I just spent a few hours debugging an issue - OpenPOP's POPClient.GetMessage() was mysteriously returning null. I debugged this and found it was a string index bug - see the patch I submitted here: http://sourceforge.net/tracker/?func=detail&aid=2833334&group_id=92166&atid=599778. It was difficult to find the cause since there are empty catch{} blocks that swallow exceptions.

Also, the project is mostly dormant... the last release was in 2004.

For now we're still using OpenPOP, but I'll take a look at some of the other projects people have recommended here.

View more solutions

Comments

[MarkJ]

Basically you're saying "buy my component", right? Nothing wrong with that, it sounds like a good component.

[Martin Vobr]

You can try any third party component (free or commercial). My post was trying to pointing out that writing of such component is both hard and time consuming because the need of extensive testing - something you hardly can do without numberous bug report with data from big number of real users. It would be nice if you choose the Rebex component, but if you choose another one I have no problem with it. Writing own MIME parser or using some proof-of-concept code found on web is IMHO in this case not the best way to go. But I may be biassed ;-), draw your own conclussion and test the code first.

[Kiquenet]

Can I use Rebex componet for get messages from Exchange 2003 inbox ??

[Martin Vobr]

@alhambraeidos: yes, you can - as long as the Exchange 2003 has either IMAP or POP3 access turned on. Check rebex.net/mail.net/faq.aspx#exchange2003 for details.

[Kiquenet]

what does recommend you ?? thx

[Kiquenet]

Can I use it for access inbox Exchange 2003 ?

[foens]

Hi. I overtook the OpenPop.NET project and brought it into a more functional state. These try catches have been removed and the library is now much more stable. I do not think this post entry is valid anymore.

[John Melville]

Author's discussion of how difficult it is to parse MIME is tainted by his comercial interest in nobody attempting it.

[Björn Franke]

Yes you can. You just need to enable IMAP or POP3 protocols.

[AbuQauod]

i've tried tyour code but there is no email body - all details come normally except body ??? any idea ?????

[ThunderGr]

Pointing out the difficulties of the MIME decoding is appreciated. However all decoders are tricky to program and debug. If everyone followed your suggestion, noone would ever try to program decoders. Stackoverflow is a community of programmers. If we should avoid doing it, who should do it???

[Martin Vobr]

@ThunderGr: good point about decoders. I guess that it depends on what is more effective. If it's easier to write your own decoder go for it. If your primary task is to get another thing done and decoding something is only part of if I would try using ready made solution. At the end of the day it's usually about balancing whether it's easier to tame a third party lib with lot of best practices build in (and deal with problems in someone's else code ) or to write it from the scratch (and deal with the fact that you probably don't know the full extent of the problem).

[razon]

link to nuget: nuget.org/packages/OpenPop.NET