C#中使用Socket获取网页源代码的代码

使用Socket获取网页源代码的代码，一般需要以下几个步骤：

1. 解析主机名和IP地址：

使用Dns类解析主机名（如www.baidu.com）对应的IP地址。代码如下：

IPHostEntry hostEntry = Dns.GetHostEntry("www.baidu.com");
IPAddress ipAddress = hostEntry.AddressList[0];

1. 建立Socket连接：

使用IPAddress和端口号建立Socket连接。代码如下：

IPEndPoint remoteEP = new IPEndPoint(ipAddress, 80);
Socket socket = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
socket.Connect(remoteEP);

1. 发送HTTP请求：

发送HTTP请求，包括请求首部和消息体（如果有），并接收服务器的响应消息。代码如下：

string request = "GET / HTTP/1.1\r\nHost: www.baidu.com\r\n\r\n";
byte[] requestBytes = Encoding.ASCII.GetBytes(request);
socket.Send(requestBytes);

1. 接收响应消息：

接收服务器的响应消息（包括响应首部和消息体），并将其转换成字符串格式。代码如下：

byte[] recvBytes = new byte[1024];
int bytes;
string response = "";
do {
    bytes = socket.Receive(recvBytes, recvBytes.Length, 0);
    response += Encoding.ASCII.GetString(recvBytes, 0, bytes);
} while (bytes > 0);

示例1：

获取百度首页的源代码：

IPAddress ipAddress = Dns.GetHostEntry("www.baidu.com").AddressList[0];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, 80);
Socket socket = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
socket.Connect(remoteEP);

string request = "GET / HTTP/1.1\r\nHost: www.baidu.com\r\n\r\n";
byte[] requestBytes = Encoding.ASCII.GetBytes(request);
socket.Send(requestBytes);

byte[] recvBytes = new byte[1024];
int bytes;
string response = "";
do {
    bytes = socket.Receive(recvBytes, recvBytes.Length, 0);
    response += Encoding.ASCII.GetString(recvBytes, 0, bytes);
} while (bytes > 0);

Console.WriteLine(response);
socket.Shutdown(SocketShutdown.Both);
socket.Close();

示例2：

获取GitHub首页的源代码：

IPAddress ipAddress = Dns.GetHostEntry("github.com").AddressList[0];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, 80);
Socket socket = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
socket.Connect(remoteEP);

string request = "GET / HTTP/1.1\r\nHost: github.com\r\n\r\n";
byte[] requestBytes = Encoding.ASCII.GetBytes(request);
socket.Send(requestBytes);

byte[] recvBytes = new byte[1024];
int bytes;
string response = "";
do {
    bytes = socket.Receive(recvBytes, recvBytes.Length, 0);
    response += Encoding.ASCII.GetString(recvBytes, 0, bytes);
} while (bytes > 0);

Console.WriteLine(response);
socket.Shutdown(SocketShutdown.Both);
socket.Close();