C++實作socket網絡通信

陳獻章：

窗外竹青青，窗間人獨坐。

究竟竹與人，原來無兩個。

狄狄：

門外日辣辣，門内清涼涼。

究竟内與外，原來差别大。

戈戈：

橋下楊柳青，橋上人獨立。

究竟柳與人，原來無分别。

詩雲：“但願人長久，千裡共婵娟”。

許多年以後，戈戈獨坐在終南山一處僻靜的茅草屋的門檻上，仰望着滿天繁星⭐，回想着那一句“山中方一日，世上已千年”。回想起從前那一個個漆黑靜谧的夜🦇，那些模糊的兒時回憶，那些一去不複返的時光，那些熟悉而又陌生的人名。一輪明月又悄悄地挂在天上🌛，時隐時現。銀紗般淡淡的光芒灑向廣袤的大地，也輕輕地灑在戈戈那總是皺着眉頭的臉頰上……

詩雲：“危樓高百尺，手可摘星辰”。

曾幾何時，戈戈常常在樓頂放一張躺椅，一躺一晚。像往常一樣靜靜地凝視着星海，那整齊排列的北鬥星，那十五皎潔的滿月🌜，以及遠方星星點點的燈光。為什麼，有些燈光總是一會開，一會滅呢……

詩雲：“竹深樹密蟲鳴處，時有微涼不是風”。

夏夜的風是令人期待的，徐徐吹來，格外清新。池塘泛起陣陣漣漪，柳枝🌿也輕輕地拂動着，心曠神怡。戈戈的思緒仿佛大雁一般長了翅膀🦆飄向那遙遠的月宮……

詩雲：“明月别枝驚鵲，清風半夜鳴蟬”。

“有人又歎氣了。”狄狄吓了一跳，“媽呀！？”，眼睛離開天上的玉盤朝四周看去，尋找剛才聲音的來處。“哦吼！沒人？”，附近哪有什麼人影👻，隻有遠處草叢若隐若現的螢火蟲飛舞🐛，以及不知哪處水坑傳來的陣陣蛙聲。狄狄試探地顫顫地輕聲問道：“你是誰？”，等了許久也沒有回應……

詩雲：“風起白蘋初日晚，霜雕紅葉欲秋分”。

秋分快到了，夜長了，天冷了，心也倦了，狄狄散完步準備回家。“珍重，網絡世界熬夜的朋友們☘️。”，又一聲，聽到這，狄狄愣了一下，看了一眼頭頂的圓月，接着朝天上揮了揮手，靜靜地朝前走去……

C++實作socket通信（windows）

1、簡介
2、TCP方式

2.1 服務端
2.2 用戶端

3、UDP方式

3.1 接收端
3.2 發送端

4、HTTP方式
後續

春有百花秋有月，夏有涼風冬有雪，若無閑事挂心頭，便是人間好時節。

1、簡介

socket顧名思義就是套接字的意思，用于描述位址和端口，是一個通信鍊的句柄。應用程式通過socket向網絡送出請求或者回應。

socket程式設計有三種，流式套接字（SOCK_STREAM）,資料報套接字(SOCK_DGRAM),原始套接字(SOCK_RAW),前兩者較常用。基于TCP的socket程式設計是流式套接字。

2、TCP方式

Server

Initialize Winsock.
Create a socket.
Bind the socket.
Listen on the socket for a client.
Accept a connection from a client.
Receive and send data.
Disconnect.

Client

Initialize Winsock.
Create a socket.
Connect to the server.
Send and receive data.
Disconnect.

2.1 服務端

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#pragma comment(lib,"Ws2_32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

int __cdecl main(void) 
{
    WSADATA wsaData;
    SOCKET ListenSocket = INVALID_SOCKET,
           ClientSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL,
                    hints;
    char recvbuf[DEFAULT_BUFLEN];
    int iResult, iSendResult;
    int recvbuflen = DEFAULT_BUFLEN;
    

    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        printf("WSAStartup failed: %d\n", iResult);
        return 1;
    }

    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;

    // Resolve the server address and port
    iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
    if ( iResult != 0 ) {
        printf("getaddrinfo failed: %d\n", iResult);
        WSACleanup();
        return 1;
    }

    // Create a SOCKET for connecting to server
    ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (ListenSocket == INVALID_SOCKET) {
        printf("socket failed: %ld\n", WSAGetLastError());
        freeaddrinfo(result);
        WSACleanup();
        return 1;
    }

    // Setup the TCP listening socket
    iResult = bind( ListenSocket, result->ai_addr, (int)result->ai_addrlen);
    if (iResult == SOCKET_ERROR) {
        printf("bind failed: %d\n", WSAGetLastError());
        freeaddrinfo(result);
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    freeaddrinfo(result);

    iResult = listen(ListenSocket, SOMAXCONN);
    if (iResult == SOCKET_ERROR) {
        printf("listen failed: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    // Accept a client socket
    ClientSocket = accept(ListenSocket, NULL, NULL);
    if (ClientSocket == INVALID_SOCKET) {
        printf("accept failed: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    // No longer need server socket
    closesocket(ListenSocket);

    // Receive until the peer shuts down the connection
    do {

        iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
        if (iResult > 0) {
            printf("Bytes received: %d\n", iResult);

        // Echo the buffer back to the sender
            iSendResult = send( ClientSocket, recvbuf, iResult, 0 );
            if (iSendResult == SOCKET_ERROR) {
                printf("send failed: %d\n", WSAGetLastError());
                closesocket(ClientSocket);
                WSACleanup();
                return 1;
            }
            printf("Bytes sent: %d\n", iSendResult);
        }
        else if (iResult == 0)
            printf("Connection closing...\n");
        else  {
            printf("recv failed: %d\n", WSAGetLastError());
            closesocket(ClientSocket);
            WSACleanup();
            return 1;
        }

    } while (iResult > 0);

    // shutdown the connection since we're done
    iResult = shutdown(ClientSocket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        printf("shutdown failed: %d\n", WSAGetLastError());
        closesocket(ClientSocket);
        WSACleanup();
        return 1;
    }

    // cleanup
    closesocket(ClientSocket);
    WSACleanup();

    return 0;
}

2.2 用戶端

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#pragma comment(lib,"Ws2_32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

int __cdecl main(int argc, char **argv) 
{
    WSADATA wsaData;
    SOCKET ConnectSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL,
                    *ptr = NULL,
                    hints;
    char *sendbuf = "this is a test";
    char recvbuf[DEFAULT_BUFLEN];
    int iResult;
    int recvbuflen = DEFAULT_BUFLEN;
    
    // Validate the parameters
    if (argc != 2) {
        printf("usage: %s server-name\n", argv[0]);
        return 1;
    }

    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        printf("WSAStartup failed: %d\n", iResult);
        return 1;
    }

    ZeroMemory( &hints, sizeof(hints) );
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    // Resolve the server address and port
    iResult = getaddrinfo(argv[1], DEFAULT_PORT, &hints, &result);
    if ( iResult != 0 ) {
        printf("getaddrinfo failed: %d\n", iResult);
        WSACleanup();
        return 1;
    }

    // Attempt to connect to an address until one succeeds
    for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {

        // Create a SOCKET for connecting to server
        ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, 
            ptr->ai_protocol);
        if (ConnectSocket == INVALID_SOCKET) {
            printf("Error at socket(): %ld\n", WSAGetLastError());
            freeaddrinfo(result);
            WSACleanup();
            return 1;
        }

        // Connect to server.
        iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
            continue;
        }
        break;
    }

    freeaddrinfo(result);

    if (ConnectSocket == INVALID_SOCKET) {
        printf("Unable to connect to server!\n");
        WSACleanup();
        return 1;
    }

    // Send an initial buffer
    iResult = send( ConnectSocket, sendbuf, (int)strlen(sendbuf), 0 );
    if (iResult == SOCKET_ERROR) {
        printf("send failed: %d\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }

    printf("Bytes Sent: %ld\n", iResult);

    // shutdown the connection since no more data will be sent
    iResult = shutdown(ConnectSocket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        printf("shutdown failed: %d\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }

    // Receive until the peer closes the connection
    do {

        iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
        if ( iResult > 0 )
            printf("Bytes received: %d\n", iResult);
        else if ( iResult == 0 )
            printf("Connection closed\n");
        else
            printf("recv failed: %d\n", WSAGetLastError());

    } while( iResult > 0 );

    // cleanup
    closesocket(ConnectSocket);
    WSACleanup();

    return 0;
}

3、UDP方式

3.1 接收端

#include <stdio.h>
#include "winsock2.h"
#pragma comment(lib,"Ws2_32.lib")

void main() {

  WSADATA wsaData;
  SOCKET RecvSocket;
  sockaddr_in RecvAddr;
  int Port = 27015;
  char RecvBuf[1024];
  int  BufLen = 1024;
  sockaddr_in SenderAddr;
  int SenderAddrSize = sizeof(SenderAddr);

  //-----------------------------------------------
  // Initialize Winsock
  WSAStartup(MAKEWORD(2,2), &wsaData);

  //-----------------------------------------------
  // Create a receiver socket to receive datagrams
  RecvSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

  //-----------------------------------------------
  // Bind the socket to any address and the specified port.
  RecvAddr.sin_family = AF_INET;
  RecvAddr.sin_port = htons(Port);
  RecvAddr.sin_addr.s_addr = htonl(INADDR_ANY);

  bind(RecvSocket, (SOCKADDR *) &RecvAddr, sizeof(RecvAddr));

  //-----------------------------------------------
  // Call the recvfrom function to receive datagrams
  // on the bound socket.
  printf("Receiving datagrams...\n");
  recvfrom(RecvSocket, 
    RecvBuf, 
    BufLen, 
    0, 
    (SOCKADDR *)&SenderAddr, 
    &SenderAddrSize);

  //-----------------------------------------------
  // Close the socket when finished receiving datagrams
  printf("Finished receiving. Closing socket.\n");
  closesocket(RecvSocket);

  //-----------------------------------------------
  // Clean up and exit.
  printf("Exiting.\n");
  WSACleanup();
  return;
}

3.2 發送端

#include <stdio.h>
#include "winsock2.h"
#pragma comment(lib,"Ws2_32.lib")

void main() {
  
  WSADATA wsaData;
  SOCKET SendSocket;
  sockaddr_in RecvAddr;
  int Port = 27015;
  char SendBuf[1024];
  int BufLen = 1024;

  //---------------------------------------------
  // Initialize Winsock
  WSAStartup(MAKEWORD(2,2), &wsaData);

  //---------------------------------------------
  // Create a socket for sending data
  SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

  //---------------------------------------------
  // Set up the RecvAddr structure with the IP address of
  // the receiver (in this example case "123.456.789.1")
  // and the specified port number.
  RecvAddr.sin_family = AF_INET;
  RecvAddr.sin_port = htons(Port);
  RecvAddr.sin_addr.s_addr = inet_addr("123.456.789.1");

  //---------------------------------------------
  // Send a datagram to the receiver
  printf("Sending a datagram to the receiver...\n");
  sendto(SendSocket, 
    SendBuf, 
    BufLen, 
    0, 
    (SOCKADDR *) &RecvAddr, 
    sizeof(RecvAddr));

  //---------------------------------------------
  // When the application is finished sending, close the socket.
  printf("Finished sending. Closing socket.\n");
  closesocket(SendSocket);

  //---------------------------------------------
  // Clean up and quit.
  printf("Exiting.\n");
  WSACleanup();
  return;
}

4、HTTP方式

無論是Http還是Https都是基于TCP進行傳輸的，是以使用SOCKET模拟HTTP通路web站點的方式，就是将頭部資料拼接成資料包，發送給服務端，然後接收傳回再解析就可以了。

這裡通過socket通路如下網易新聞api接口網址擷取對應資料：

http://data.live.126.net/livechannel/classifylist.json

#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#pragma comment(lib,"Ws2_32.lib")

#define DEFAULT_BUFLEN 4086
#define DEFAULT_PORT 80
#define DEFAULT_URL "/livechannel/classifylist.json"
#define DEFAULT_DOMAIN "data.live.126.net"

void get_ip_addr(const char *domain, char *ip_addr)
{
  /*通過域名得到相應的ip位址*/
  struct hostent *host = gethostbyname(domain);
  if (!host)
  {
    ip_addr = NULL;
    return;
  }

  for (int i = 0; host->h_addr_list[i]; i++)
  {
    strcpy(ip_addr, inet_ntoa(*(struct in_addr*) host->h_addr_list[i]));
    break;
  }
}

int __cdecl main(int argc, char **argv)
{
  WSADATA wsaData;
  SOCKET ConnectSocket = INVALID_SOCKET;
  const char *sendbuf = "this is a test";
  char recvbuf[DEFAULT_BUFLEN];
  int iResult;
  int recvbuflen = DEFAULT_BUFLEN;

  // Initialize Winsock
  iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
  if (iResult != 0) {
    printf("WSAStartup failed: %d\n", iResult);
    return 1;
  }

  char szRemoteIPAddr[128];
  get_ip_addr(DEFAULT_DOMAIN, szRemoteIPAddr);

  // Create a SOCKET for connecting to server
  ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (ConnectSocket == INVALID_SOCKET) {
    printf("Error at socket(): %ld\n", WSAGetLastError());
    WSACleanup();
    return 1;
  }

  struct sockaddr_in serverAddr;
  serverAddr.sin_family = AF_INET;
  serverAddr.sin_port = htons(DEFAULT_PORT);
  serverAddr.sin_addr.s_addr = inet_addr(szRemoteIPAddr);

  // Connect to server.
  iResult = connect(ConnectSocket, (struct sockaddr *)&serverAddr, sizeof(serverAddr));
  if (iResult == SOCKET_ERROR) {
    closesocket(ConnectSocket);
    ConnectSocket = INVALID_SOCKET;
    return 1;
  }

  // Send an initial buffer
  std::string head = "GET " DEFAULT_URL " HTTP/1.1\r\n";
  head.append("Host: " DEFAULT_DOMAIN "\r\n");//請求的域名
  head.append("Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\n");
  head.append("User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.120 Safari/537.36\r\n");
  head.append("Accept-Language: zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3\r\n");
  head.append("Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7");
  head.append("Accept-Encoding: gzip,deflate\r\n");
  head.append("\r\n");//表明請求頭結束了

  iResult = send(ConnectSocket, head.c_str(), (int)head.size(), 0);
  if (iResult == SOCKET_ERROR) {
    printf("send failed: %d\n", WSAGetLastError());
    closesocket(ConnectSocket);
    WSACleanup();
    return 1;
  }

  printf("Bytes Sent: %ld\n", iResult);

  // Receive until the peer closes the connection
  do {
    memset(recvbuf, 0, sizeof(recvbuf));
    iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
    if (iResult > 0) {
      printf("Bytes received: %d\n", iResult);
      printf(recvbuf);
    }
    else if (iResult == 0)
      printf("Connection closed\n");
    else
      printf("recv failed: %d\n", WSAGetLastError());

  } while (iResult > 0);

  // cleanup
  closesocket(ConnectSocket);
  WSACleanup();

  return 0;
}

C++實作socket網絡通信

C++實作socket通信（windows）

1、簡介

2、TCP方式

2.1 服務端

2.2 用戶端

3、UDP方式

3.1 接收端

3.2 發送端

4、HTTP方式

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