This is one of my few attempts at writing a .NET core app and it is using .NET core 2.1.
I'm writing a program to read emails from a POP3 server that will ultimately populate get the message id, date received, who sent the email, and the message (plain text). This is what I have so far:
The issue that I'm running into is that as soon as I create the lines variable in my For/Next loop, the line hangs and won't go to the next line. In other words, I setup a break point, try to step over, and the next line never breaks. This happens even if I try to read the stream line by line like this:
What could be causing this?
I'm writing a program to read emails from a POP3 server that will ultimately populate get the message id, date received, who sent the email, and the message (plain text). This is what I have so far:
Code:
' create a TCP client
Using client = New TcpClient()
' connect to the POP3 server
client.Connect(Server, Port)
' get the network stream to send/receive data
Using pop3Stream = client.GetStream()
' create and connect to a SSL stream to send the commands
Using sslStream = new SslStream(pop3Stream)
sslStream.AuthenticateAsClient(Server)
' get the stream reader to read the results
Using reader = new StreamReader(sslStream)
reader.ReadLine()
' send the username part of the authentication
Dim command = $"USER {Username}{Environment.NewLine}"
Dim buffer = Encoding.ASCII.GetBytes(command.ToCharArray())
sslStream.Write(buffer, 0, buffer.Length)
reader.ReadLine()
' send the password part of the authentication
command = $"PASS {Password}{Environment.NewLine}"
buffer = Encoding.ASCII.GetBytes(command.ToCharArray())
sslStream.Write(buffer, 0, buffer.Length)
reader.ReadLine()
' the STAT command displays the number of messages currently in the mailbox and the size (in bytes)
command = $"STAT{Environment.NewLine}"
buffer = Encoding.ASCII.GetBytes(command.ToCharArray())
sslStream.Write(buffer, 0, buffer.Length)
Dim line = reader.ReadLine()
' get just the number of messages, an example of what the line variable would be like is: +OK 1 1322
' we need just the middle part
Dim total = line.Split(" "c, StringSplitOptions.RemoveEmptyEntries)(1)
' loop from 1 to the total, if there are 0 messages then the loop will be skipped
For index = 1 To Convert.ToInt32(total)
' the RETR command will actually get the content of the message
' the last line of the message with be a full stop on a single line followed by a CRLF to indicate the end of the message
command = $"RETR {index} {Environment.NewLine}"
buffer = Encoding.ASCII.GetBytes(command.ToCharArray())
sslStream.Write(buffer, 0, buffer.Length)
Dim lines = reader.ReadToEnd().Split(Environment.NewLine).ToList()
If (lines.Any(Function(l) l.StartsWith("New Entry:"))) Then
Dim messageId = lines.FirstOrDefault(Function(l) l.StartsWith("Message-ID:")).Replace("Message-ID:", String.Empty)
Dim dateReceived = lines.FirstOrDefault(Function(l) l.StartsWith("Date:")).Replace("Date:", String.Empty)
Dim from = lines.FirstOrDefault(Function(l) l.StartsWith("From:")).Replace("From:", String.Empty)
Dim row = New ExcelRow With {
.DateReceived = dateReceived,
.From = from,
.MessageId = messageId
}
Dim messageStartingIndex = lines.IndexOf("Content-Disposition: inline") + 1
Dim messageEndingIndex = lines.IndexOf("Content-Type: text/html; charset=""utf-8""") - 2
row.Message = String.Join(Environment.NewLine, lines.Skip(messageStartingIndex).Take(messageEndingIndex - messageStartingIndex))
Console.WriteLine(row.Message)
Console.WriteLine("{0}********************************{0}", Environment.NewLine)
End If
Next
End Using
End Using
End Using
End UsingCode:
Dim lines = New List(Of String)
Dim line = reader.ReadLine()
Do While line <> environment.NewLine
lines.Add(line)
line = reader.ReadLine()
Loop
