C#實現Web服務器

學習C#時，經常會遇到Web服務器功能的程序設計問題，這里將介紹C#實現Web服務器功能的程序設計問題的解決方法。

C#實現Web服務器功能的程序設計

根據HTTP協議的作用原理，實現GET請求的Web服務器程序的方法如下：

創建TcpListener類對象，監聽某端口（任意輸入閑置端口 如：8080 ）。等待、接受客戶機連接到該端口，得到與客戶機連接的socket;從與socket關聯的輸入流中讀取一行客戶機提交的請求信息，請求信息的格式 為：GET 路徑/文件名 HTTP/1.0。從請求信息中獲取請求類型。如果請求類型是GET，則從請求信息中獲取所訪問的HTML文件名。沒有HTML文件名時，則以 index.html作為文件名；

如果HTML文件存在，則打開HTML文件，把HTTP頭信息和HTML文件內容通過socket傳回給Web瀏覽器，然后關閉文件。否則發送錯誤信息給Web瀏覽器；關閉與相應Web瀏覽器連接的socket字。

C#實現Web服務器功能的代碼如下：

    using System;  
    using System.IO;  
    using System.Net;  
    using System.Net.Sockets;  
    using System.Text;  
    using System.Threading ;  

    class MyWebServer  
    {  

    private TcpListener myListener ;  
    private int port = 8080 ; // 選者任何閑置端口  

    //開始兼聽端口  
    //同時啟動一個兼聽進程  
    public MyWebServer()  
    {  
    try  
    {  
    //開始兼聽端口  
    myListener = new TcpListener(port) ;  
    myListener.Start();  
    Console.WriteLine("Web Server Running... Press ^C to Stop...");  
    //同時啟動一個兼聽進程 ''StartListen''  
    Thread th = new Thread(new ThreadStart(StartListen));  
    th.Start() ;  

    }  
    catch(Exception e)  
    {  
    Console.WriteLine("兼聽端口時發生錯誤 :" +e.ToString());  
    }  
    }  
    public void SendHeader(string sHttpVersion, string sMIMEHeader, 
    int iTotBytes, string sStatusCode, ref Socket mySocket)  
    {  

    String sBuffer = "";  

    if (sMIMEHeader.Length == 0 )  
    {  
    sMIMEHeader = "text/html"; // 默認 text/html  
    }  

    sBuffersBuffer = sBuffer + sHttpVersion + sStatusCode + "\r\n";  
    sBuffersBuffer = sBuffer + "Server: cx1193719-b\r\n";  
    sBuffersBuffer = sBuffer + "Content-Type: " + sMIMEHeader + "\r\n";  
    sBuffersBuffer = sBuffer + "Accept-Ranges: bytes\r\n";  
    sBuffersBuffer = sBuffer + "Content-Length: " + iTotBytes + "\r\n\r\n";  

    Byte[] bSendData = Encoding.ASCII.GetBytes(sBuffer);  

    SendToBrowser( bSendData, ref mySocket);  

    Console.WriteLine("Total Bytes : " + iTotBytes.ToString());  

    }  

    public void SendToBrowser(String sData, ref Socket mySocket)  
    {  
    SendToBrowser (Encoding.ASCII.GetBytes(sData), ref mySocket);  
    }  

    public void SendToBrowser(Byte[] bSendData, ref Socket mySocket)  
    {  
    int numBytes = 0;  

    try  
    {  
    if (mySocket.Connected)  
    {  
    if (( numBytes = mySocket.Send(bSendData, bSendData.Length,0)) == -1)  
    Console.WriteLine("Socket Error cannot Send Packet");  
    else  
    {  
    Console.WriteLine("No. of bytes send {0}" , numBytes);  
    }  
    }  
    else  
    Console.WriteLine("連接失敗....");  
    }  
    catch (Exception e)  
    {  
    Console.WriteLine("發生錯誤 : {0} ", e );  

    }  
    }  
    public static void Main()  
    {  
    MyWebServer MWS = new MyWebServer();  
    }  
    public void StartListen()  
    {  

    int iStartPos = 0;  
    String sRequest;  
    String sDirName;  
    String sRequestedFile;  
    String sErrorMessage;  
    String sLocalDir;  

    String sMyWebServerRoot = "E:\\MyWebServerRoot\\"; //設置你的虛擬目錄  

    String sPhysicalFilePath = "";  
    String sFormattedMessage = "";  
    String sResponse = "";  

    while(true)  
    {  
    //接受新連接  
    Socket mySocket = myListener.AcceptSocket() ;  

    Console.WriteLine ("Socket Type " +mySocket.SocketType );  
    if(mySocket.Connected)  
    {  
    Console.WriteLine("\nClient Connected!!\n=\nCLient IP {0}\n",mySocket.RemoteEndPoint) ;  

    Byte[] bReceive = new Byte[1024] ;  
    int i = mySocket.Receive(bReceive,bReceive.Length,0) ;  

    //轉換成字符串類型  
    string sBuffer = Encoding.ASCII.GetString(bReceive);  


    //只處理"get"請求類型  
    if (sBuffer.Substring(0,3) != "GET" )  
    {  
    Console.WriteLine("只處理get請求類型..");  
    mySocket.Close();  
    return;  
    }  

    // 查找 "HTTP" 的位置  
    iStartPos = sBuffer.IndexOf("HTTP",1);  

    string sHttpVersion = sBuffer.Substring(iStartPos,8);  

    // 得到請求類型和文件目錄文件名  
    sRequest = sBuffer.Substring(0,iStartPos - 1);  

    sRequest.Replace("\\","/");  

    //如果結尾不是文件名也不是以"/"結尾則加"/"  
    if ((sRequest.IndexOf(".") <1) && (!sRequest.EndsWith("/")))  
    {  
    sRequestsRequest = sRequest + "/";  
    }  

    //得帶請求文件名  
    iStartPos = sRequest.LastIndexOf("/") + 1;  
    sRequestsRequestedFile = sRequest.Substring(iStartPos);  

    //得到請求文件目錄  
    sDirName = sRequest.Substring(sRequest.IndexOf("/"), sRequest.LastIndexOf("/")-3);  

    //獲取虛擬目錄物理路徑  
    sLocalDir = sMyWebServerRoot;  

    Console.WriteLine("請求文件目錄 : " + sLocalDir);  

    if (sLocalDir.Length == 0 )  
    {  
    sErrorMessage = "<H2>Error!! Requested Directory does not exists</H2><Br>";  
    SendHeader(sHttpVersion, "", sErrorMessage.Length, " 404 Not Found", ref mySocket);  
    SendToBrowser(sErrorMessage, ref mySocket);  
    mySocket.Close();  
    continue;  
    }  

    if (sRequestedFile.Length == 0 )  
    {  
    // 取得請求文件名  
    sRequestedFile = "index.html";  
    }  


    String sMimeType = "text/html";  

    sPhysicalFilePath = sLocalDir + sRequestedFile;  
    Console.WriteLine("請求文件: " + sPhysicalFilePath);  

    if (File.Exists(sPhysicalFilePath) == false)  
    {  

    sErrorMessage = "<H2>404 Error! File Does Not Exists...</H2>";  
    SendHeader(sHttpVersion, "", sErrorMessage.Length, " 404 Not Found", ref mySocket);  
    SendToBrowser( sErrorMessage, ref mySocket);  

    Console.WriteLine(sFormattedMessage);  
    }  

    else  
    {  
    int iTotBytes=0;  

    sResponse ="";  

    FileStream fs = new FileStream(sPhysicalFilePath, 
    FileMode.Open, FileAccess.Read, FileShare.Read);  

    BinaryReader reader = new BinaryReader(fs);  
    byte[] bytes = new byte[fs.Length];  
    int read;  
    while((read = reader.Read(bytes, 0, bytes.Length)) != 0)  
    {  
    sResponsesResponse = sResponse + Encoding.ASCII.GetString(bytes,0,read);  

    iTotBytesiTotBytes = iTotBytes + read;  

    }  
    reader.Close();  
    fs.Close();  

    SendHeader(sHttpVersion, sMimeType, iTotBytes, " 200 OK", ref mySocket);  
    SendToBrowser(bytes, ref mySocket);  
    //mySocket.Send(bytes, bytes.Length,0);  
    }  
    mySocket.Close();  
    }  
    }  
    }  
    }  
    }