.Net POP3 客户端

Question

<分区>

Answer 1

The F#.NET Journal文章 An e-mail client in F# (2010 年 3 月 31 日)描述了如何仅用几行 F# 代码编写您自己的代码，以以下序列表达式为中心:

> let receive =
    seq { use client = new Sockets.TcpClient(Server.pop3.addr, Server.pop3.port)
          use stream = client.GetStream()
          use reader = new System.IO.StreamReader(stream)
          let rec readToDot() =
            let line = reader.ReadLine()
            if line <> "." then line + "\n" + readToDot() else ""
          reader.ReadLine() |> ignore
          use writer = new System.IO.StreamWriter(stream)
          let write (line: string) =
            writer.Write(line + "\n")
            writer.Flush()
          write "USER myname"
          reader.ReadLine() |> ignore // +OK Password required.
          write "PASS mypassword"
          reader.ReadLine() |> ignore // +OK logged in.
          write "STAT"
          let stat = reader.ReadLine() // +OK <message count> <total size>
          for i in 1 .. int (stat.Split[|' '|]).[1] do
            write(sprintf "RETR %d" i)
            reader.ReadLine() |> ignore // +OK <message size> octets follow.
            match readToDot() |> parse with
            | Some msg -> yield msg
            | None -> ()
          write "QUIT"
          reader.ReadLine() |> ignore };;
val receive : seq<msg>