在POP3的基本作業(Basic Operation)提到了幾個基本的操作；而事實上這幾個操作都包含在POP3 == RFC 1939一文中所提到的POP3Client類別(Class)裡。這個類別原來是用C#(C Sharp)寫的，最近亞伯特把它整理了一下，同時也改寫成VB以及VC++以供參考。 連接POP3伺服器函數(Function) Connect() 這個函數使用型別為TcpClient的物件(tcClient)來連接POP3伺服器；在連接的同時，這個函數會建立一個型別為NetwrokStream的物件(nsStream)，這個物件用夾提供網路存取資料的功能；呼叫它時，必須提供伺服器稱(例如HiNet的郵件伺服器，ms1.hinet.net)以及埠號(按照POP3，通常是110)。函數在結束時呼叫函數GetResponse()，這個函數負責透過nsStream讀取伺服器回應的訊息，並且判斷連結是否成功： [VB 的程式碼] Public Function Connect(ByVal Server As String, ByVal Port As Integer) As Boolean '--- 連接伺服器/Connect to POP3 server ------------------------------ Try tcClient = New TcpClient(Server, Port) nsStream = tcClient.GetStream() nsStream.ReadTimeout = 15000 Catch Throw End Try Return GetResponse() End Function [VC#的程式碼] public bool Connect(string Server, int Port) { //--- 連接伺服器/Connect to POP3 server ------------------------------ try { tcPOP3Client = new TcpClient(Server, Port); nsStream = tcPOP3Client.GetStream(); nsStream.ReadTimeout = 15000; } catch (SocketException) { throw; } return GetResponse(); } [VC++的程式碼] bool CPOP3Client::Connect(String^ Server, int Port) { //--- 連接伺服器/Connect to POP3 server ------------------------------ try { tcPOP3Client = gcnew TcpClient(Server, Port); nsStream = tcPOP3Client->GetStream(); nsStream->ReadTimeout = 15000; } catch (...) { throw; } return GetResponse(); } 登錄POP3伺服器函數Logon() 它藉著呼叫函數Request()執行登錄的動作 ；Request函數是透過nsStream把要求傳給伺服器，然後呼叫GetResponse()函數取得回應的訊息，並且藉由該訊息判斷是否登錄成功： [VB 的程式碼] Public Function Logon(ByVal Username As String, ByVal Password As String) As Boolean '--- 登錄郵件伺服器/Logon POP3 server -------------------------------- ' Return Request("USER", Username) And Request("PASS", Password) End Function [VC#的程式碼] public bool Logon(string UserName, string Password) { //--- 登錄郵件伺服器/Logon POP3 server -------------------------------- return Request("USER", UserName) && Request("PASS", Password); } [VC++的程式碼] bool CPOP3Client::Logon(String^ UserName, String^ Password) { //--- 登錄郵件伺服器/Logon POP3 server -------------------------------- return Request("USER", UserName) && Request("PASS", Password); } [VB 的程式碼] Private Function Request(ByVal Command As String) '--- 傳送指令給伺服器/Request POP3Server ----------------------------- Dim bytCommand() As Byte = Encoding.ASCII.GetBytes(Command & vbCrLf) nsStream.Write(bytCommand, 0, bytCommand.Length) Return GetResponse() End Function [VC#的程式碼] private bool Request(string Command) { //--- 傳送指令給伺服器/Request POP3Server ----------------------------- Byte[] bytCommand; bytCommand = Encoding.ASCII.GetBytes(Command + "\r\n"); nsStream.Write(bytCommand, 0, bytCommand.Length); return GetResponse(); } [VC++的程式碼] bool CPOP3Client::Request(String^ Command) { //--- 傳送指令給伺服器/Request POP3Server ----------------------------- array<Byte>^ bytCommand; bytCommand =Encoding::ASCII->GetBytes(Command + "\r\n"); nsStream->Write(bytCommand, 0, bytCommand->Length); return GetResponse(); } 讀取伺服器回應訊息的函數GetResponse() 如前所述，GetResponse()是透過nsStream讀取伺服器的回應訊息；所以GetResponse()不但要正確的取得伺服器的回應，而且要判斷該訊息是成功(+OK)的訊息或者是失敗(-ERR)的訊息。 [VB 的程式碼] Public Function GetResponse() As Boolean '--- 讀取伺服器回應的資料/Get response from POP3 server --------------- Dim iBytes As Integer Dim bOk As Boolean Try '--- 讀取資料/Getting Data -------------------------------------- iBytes = nsStream.Read(bytData, 0, bytData.Length) strResponse = Encoding.ASCII.GetString(bytData, 0, iBytes) bOk = strResponse.StartsWith("+OK") '--- 多行的處理/For multi-line ----------------------------------- If (strResponse.IndexOf(vbCrLf) < (iBytes - 2)) Then Do While Not (strResponse.EndsWith("." & vbCrLf)) iBytes = nsStream.Read(bytData, 0, bytData.Length) strResponse &= Encoding.ASCII.GetString(bytData, 0, iBytes) Loop strResponse = strResponse.Substring(0, strResponse.Length - 3) strResponse = Unfolding(strResponse) End If If bOk Then strResponse = strResponse.Substring(3) _ Else strResponse.Substring(4) strResponse = strResponse.TrimStart() Catch bOk = False End Try Return bOk End Function [VC#的程式碼] private bool GetResponse() { //--- 讀取伺服器回應的資料/Get response from POP3 server --------------- int iBytes; bool bOK = false; try { //--- 讀取資料/Getting Data -------------------------------------- iBytes = nsStream.Read(bytData, 0, bytData.Length); strResponse = Encoding.ASCII.GetString(bytData, 0, iBytes); bOK = strResponse.StartsWith("+OK"); //--- 多行的處理/For multi-line ----------------------------------- if ((strResponse.IndexOf("\r\n") < (iBytes - 2))) { while (!strResponse.EndsWith(".\r\n")) { iBytes = nsStream.Read(bytData, 0, bytData.Length); strResponse += Encoding.ASCII.GetString(bytData, 0, iBytes); } strResponse = strResponse.Substring(0, strResponse.Length - 3); strResponse = Unfolding(strResponse); } if (bOK) strResponse = strResponse.Substring(3); else strResponse.Substring(4); strResponse = strResponse.TrimStart(); } catch (IOException) { bOK = false; } return bOK; } [VC++的程式碼] bool CPOP3Client::GetResponse() { //--- 讀取伺服器回應的資料/Get response from POP3 server --------------- int iBytes; bool bOK = false; try { //--- 讀取資料/Getting Data -------------------------------------- iBytes = nsStream->Read(bytData, 0, bytData->Length); strResponse = Encoding::ASCII->GetString(bytData, 0, iBytes); bOK = strResponse->StartsWith("+OK"); //--- 多行的處理/For multi-line ----------------------------------- if ((strResponse->IndexOf("\r\n") < (iBytes - 2))) { while (!strResponse->EndsWith(".\r\n")) { iBytes = nsStream->Read(bytData, 0, bytData->Length); strResponse += Encoding::ASCII->GetString(bytData, 0, iBytes); } strResponse = strResponse->Substring(0, strResponse->Length - 3); strResponse = Unfolding(strResponse); } strResponse=bOK?strResponse->Substring(3):strResponse->Substring(4); strResponse=strResponse->TrimStart(); } catch (...) { bOK = false; } return bOK; }
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