Retrieving email from POP3 server using C#
This article will demonstrate how using the Email Factory for .NET Pop component you can retrieve emails from a POP3 server using C#. To see what else Email Factory for .NET has to offer Download a FREE 30 day Email Factory for .NET Evaluation.
The Email Factory for .NET Pop component provides methods for communicating with an POP3 server. Using the Email Factory for .NET components retrieving email from a POP3 or IMAP server is a very simple task. For the purposes of this article we will focus on using the POP3 protocol. Details of using the IMAP protocol to retrieve email are very much the same, the main difference being that the Pop class is used instead of the Imap class.
The process for establishing an interactive session with an POP3 server using the Email Factory for .NET component is as follows:
- Creating a new Pop instance
- Subscribing to Pop Events
- Establishing a connection
- Retrieving one or more Email messages
- Saving attachments to disk
- Reading message attributes
- Releasing a connection
Each of these processes is described in the sections below.
Before creating a new Pop instance, ensure that the Jscape.Email scope is defined in your using statements, and that the Jscape.Email.dll is referenced in your project. Refer to Getting Started in the Email Factory for .NET Help for more information about adding the Jscape.Email.dll reference to your projects.
Create a new Pop instance providing the POP3 server hostname, username, and password as arguments.
Pop myPop = new Pop("hostname", "username", "password");
The Pop instance MUST subscribe to the Pop events prior to invoking the Connect() method to ensure that all data sent by the POP3 server is captured.
The Pop component may publish one or more events during the lifetime of an Pop session. Any object that subscribes to events published by the Pop component can receive and process the following events.
- The
ConnectedEvent is fired by the Pop instance once a connection to the POP server has been established.
- The
DisconnectedEvent is fired by the Pop instance once the connection to the POP server has been released.
- The
CommandSentEvent is fired by the Pop instance for each command sent to the POP server.
- The
DataReceivedEvent is fired by the Pop instance for each response received from the POP server.
- The
MessageRetrievedEvent is fired by the Pop instance for each message retrieved from the POP server.
The following example illustrates subscribing to the Pop component events.
// Subscribe to events
myPop.ConnectedEvent += new Pop.ConnectedEventHandler(OnConnected);
myPop.DisconnectedEvent += new Pop.DisconnectedEventHandler(OnDisconnected);
myPop.DataReceivedEvent += new Pop.DataReceivedEventHandler(OnDataReceived);
myPop.CommandSentEvent += new Pop.CommandSentEventHandler(OnCommandSent);
myPop.MessageRetrievedEvent += new Pop.MessageRetrievedEventHandler(OnMessageRetrieved);
Now you can create the event handler methods you previously defined when subscribing to the Pop events.
public void OnConnected(object sender, PopConnectedEventArgs e) {
Console.WriteLine("Connected to {0}", e.Host);
}
public void OnDisconnected(object sender, PopDisconnectedEventArgs e) {
if (myPop.IsConnected()) {
myPop.Disconnect();
}
Console.WriteLine("Disconnected.");
}
public void OnDataReceived(object sender, PopDataReceivedEventArgs e) {
Console.WriteLine("Response: "+e.Response);
}
public void OnCommandSent(object sender, PopCommandSentEventArgs e) {
Console.WriteLine("Command: "+e.Command);
}
public void OnMessageRetrieved(object sender, PopMessageRetrievedEventArgs e) {
Console.WriteLine("Message:\r\n"+e.Message.GetSubject());
}
Once a Pop instance has been created and subscribed to the Pop events you may establish a connection to the POP server by invoking the Connect() method.
myPop.Connect();
Upon establishing a connection to a POP server you can retrieve all messages in the Pop account mailbox by invoking the GetMessages method. Any messages found are returned as an Enumeration.
IEnumerator e = myPop.GetMessages();
while(e.MoveNext()) {
EmailMessage em = (EmailMessage)e.Current;
}
Additionally, you can retrieve a message in the account mailbox by invoking the GetMessage method and passing the one-based message ID as an argument.
// get the first message
EmailMessage message = myPop.GetMessage(1);
Once you have retrieved an email message you can then retrieve any attachments and save them to disk.
int mc = 0;
int ac = 0;
IEnumerator e = myPop.GetMessages();
while(e.MoveNext()) {
++mc;
EmailMessage message = (EmailMessage)e.Current;
// get attachments for each email
IEnumerator ea = message.GetAttachments();
while(ea.MoveNext()) {
++ac;
Attachment a = (Attachment)ea.Current;
// get name of attached file, if any
String filename = a.GetFilename();
if (filename.Length == 0) {
// build temporary filename
filename = "att" + mc + "_" + ac + ".txt";
}
// get data for attached file
byte[] data = a.GetFileData();
// process the attachment
FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Write);
BinaryWriter w = new BinaryWriter(fs);
w.Write(data, 0, data.Length);
fs.Close();
}
}
The Email Factory for .NET Pop component contains methods and properties for reading message attributes, such as the Subject, Body, Content-Type, From address, etc.
IEnumerator e = myPop.GetMessages();
while(e.MoveNext()) {
EmailMessage em = (EmailMessage)e.Current;
// display message subject
Console.Write(em.Subject + "\t");
// display From address
Console.Writeline(em.From);
// display message content type
Console.Writeline(em.GetContentType());
}
To release an established connection simply invoke the Disconnect() method as follows:
myPop.Disconnect();
The source code for this article is available for download and for viewing.
View example source code
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