Пример работы с сокетами для Windows

Писал, когда сам разбирался с этим делом. На базе этого простого примера написано (точнее не совсем на его базе, а скорее при его участии) пара серьезных программок.

Все просто, как в танке. По исходникам разберетесь.

makefile

all: socket.cpp config.h socket.h
 $(CC) socket.cpp

socket.cpp

#include "stdio.h";
#include "socket.h";
#include "config.h";

static char Rec[2048000];

bool SendString(SOCKET s,char* str) {
int cnt=send(s,str,strlen(str),0);
if (cnt==SOCKET_ERROR) return(false); else return(true);
}

char* GetString(SOCKET s) {
char *str;
char InBuff[2048];
int cnt;

strcpy("",Rec);
while (cnt!=0) {
memset(&InBuff,0,2048);
 cnt=recv (s, (char*)&InBuff, sizeof(InBuff),0);
strcat(Rec,InBuff);
}
return((char*)&Rec);
}


int OpenURL(char *url) {
char *none="";
char query[2048];
struct sockaddr_in ssin;
struct hostent* hp;
unsigned char strHlp[2048], *pch;
int PortNum;
char *https_host;
char *https_path;

if (memcmp(url,"HTTP://",7)!=0 && memcmp(url,"https://",7)!=0) return(7);
url+=7;
if (WSAStartup(MAKEWORD(1,1),&lpWSAData)!=0) return(1);
// используем Default'овый номер порта - 80, если не задан другой
strcpy(strHlp,url);
pch = strchr((char*)strHlp,':');
if (pch==NULL) {
PortNum = 80;
pch = strchr((char*)strHlp,'/');
if (pch!=NULL) {
pch[0] = '\0';
https_path=pch+1;
}
else {
https_path=none;
}
}
else {
pch[0] = '\0';
pch++;
char *pch1 = strchr((char*)pch,'/');
if (pch1!=NULL) {
pch1[0] = '\0';
https_path=pch1+1;
}
else {
https_path=none;
}
PortNum = atoi(pch);
if(PortNum==0) PortNum = 80;
}

// Поучаем IP по имени
if ((hp=gethostbyname(strHlp))==NULL) return(1);
https_host=strHlp;

memset ((char *)&ssin, 0, sizeof(ssin));
ssin.sin_family = AF_INET;
ssin.sin_addr.s_addr = htonl(INADDR_ANY);
ssin.sin_port = 0;
bind (s, (struct sockaddr *)&ssin, sizeof(ssin));

s=socket(AF_INET, SOCK_STREAM, 0);
if (s==INVALID_SOCKET) return(4);

ssin.sin_family = AF_INET;
ssin.sin_addr.S_un.S_un_b.s_b1 = hp->h_addr[0];
ssin.sin_addr.S_un.S_un_b.s_b2 = hp->h_addr[1];
ssin.sin_addr.S_un.S_un_b.s_b3 = hp->h_addr[2];
ssin.sin_addr.S_un.S_un_b.s_b4 = hp->h_addr[3];
ssin.sin_port = htons(PortNum);

printf("Conecting to %d.%d.%d.%d...",
(unsigned char)hp->h_addr[0],
(unsigned char)hp->h_addr[1],
(unsigned char)hp->h_addr[2],
(unsigned char)hp->h_addr[3]);
if (connect(s, (sockaddr *)&ssin, sizeof(ssin))==-1) return(3);
printf("Ok\n");

strcpy(query,"GET /");
strcat(query,https_path);
strcat(query," HTTP/1.0\nHost: ");
strcat(query,https_host);
strcat(query,"\nUser-agent: ");
strcat(query,https_user_agent);
strcat(query,"\nAccept: */*\n\n");

printf("%s",query);

if (!SendString(s,query)) return(5);
char* str=GetString(s);
printf("%s",str);
return(0);
}

void CloseURL(void) {
WSACleanup();
}
 
void main(void) { 
int err=OpenURL("https://www.codenet.ru/");
if (err!=0) {
printf("Error #%d: WSABASEERR+%d\n",err,
WSAGetLastError()-WSABASEERR);
}
}

config.h

Этот модуль содержит настройки...точнее одну настройку - то что сервер получит в качестве HTTP_USER_AGENT.

char *https_user_agent="Search Engine";

socket.h

#include <windows.h>

int s;
WSADATA lpWSAData;

#include "stdio.h"
#include "socket.h"
#include "config.h"

static char Rec[2048000];
//
// routine for send request in 'str' to socket in 's'
//
bool SendString(SOCKET s,char* str) 
{
int cnt = send(s,str,strlen(str),0);
if (cnt == SOCKET_ERROR) return(false); else return(true);
}

//
// routine for receive entire information from 's'
// socket and store it in 'Rec' buffer
//
char* GetString(SOCKET s) 
{
char *str;
char InBuff[2048];
int cnt;

strcpy("",Rec);
while (cnt!=0) {
 // clear InBuff - fill 2048 bytes to NULL
 memset(&InBuff,0,2048);
 // receive a 2048 bytes from 's' sock
 cnt = recv (s, (char*)&InBuff, sizeof(InBuff),0);
// append it to main buffer 'Rec'
strcat(Rec,InBuff);
}
return((char*)&Rec);
}


//
// routine to
//
int OpenURL(char *url) {
 // empty string
char *none="";
 // string for send request to server
char query[2048];
struct sockaddr_in ssin;
struct hostent* hp;
char strHlp[2048], *pch;
int PortNum;
char *https_host;
char *https_path;

// ensure that url starts with "HTTP://" or "https://"
if (memcmp(url,"HTTP://",7)!=0 && memcmp(url,"https://",7)!=0) 
return(7);
url+=7;// seek "https://"
// initialize structure WSADATA lpWSAData defined in 'socket.h'
if (WSAStartup(MAKEWORD(1,1),&lpWSAData)!=0) 
return(1);
// use default port number - 80 if not specified other
 // strHlp - helper string that contains server name and path on the server
strcpy(strHlp,url);
pch = strchr((char*)strHlp,':');
// port not defined in passed URL
if (pch==NULL) {
PortNum = 80;
}
// port defined in passed URL
else {
pch[0] = '\0'; // truncate port from URL
PortNum = atoi(++pch);
if(PortNum == 0) PortNum = 80;
}

// separate server name from path on server
pch = strchr((char*)strHlp,'/');
if (pch!=NULL) {
pch[0] = '\0';
https_path=pch+1;
}
else {
https_path=none;
}

// Get Host IP by Host name
if ((hp = gethostbyname(strHlp)) == NULL) 
return(1);
https_host = strHlp;

 // clear sockaddr_in ssin structure
memset ((char *)&ssin, 0, sizeof(ssin));
ssin.sin_family = AF_INET;
ssin.sin_addr.s_addr = htonl(INADDR_ANY);
ssin.sin_port = 0;
 // associate ssin with a socket 's'
bind (s, (struct sockaddr *)&ssin, sizeof(ssin));

s = socket(AF_INET, SOCK_STREAM, 0);
if (s==INVALID_SOCKET) return(4);

ssin.sin_family = AF_INET;
ssin.sin_addr.S_un.S_un_b.s_b1 = hp->h_addr[0];
ssin.sin_addr.S_un.S_un_b.s_b2 = hp->h_addr[1];
ssin.sin_addr.S_un.S_un_b.s_b3 = hp->h_addr[2];
ssin.sin_addr.S_un.S_un_b.s_b4 = hp->h_addr[3];
ssin.sin_port = htons(PortNum);

printf("Conecting to %d.%d.%d.%d...",
(unsigned char)hp->h_addr[0],
(unsigned char)hp->h_addr[1],
(unsigned char)hp->h_addr[2],
(unsigned char)hp->h_addr[3]);
// establish a connection with socket 's'
if (connect(s, (sockaddr *)&ssin, sizeof(ssin)) == -1) 
return(3);
printf("Ok\n");

strcpy(query,"GET /");
strcat(query,https_path);
strcat(query," HTTP/1.0\nHost: ");
strcat(query,https_host);
strcat(query,"\nUser-agent: ");
strcat(query,https_user_agent);
strcat(query,"\nAccept: */*\n\n");

printf("%s",query);

// send request
if (!SendString(s,query)) return(5);
// receive response
char* str = GetString(s);
printf("%s",str);
return(0);
}

void CloseURL(void) {
WSACleanup();
}
 
void main(void) 
{ 
int err=OpenURL("https://www.codenet.ru/");
if (err != 0) {
printf("Error #%d: WSABASEERR+%d\n",err,
WSAGetLastError()-WSABASEERR);
}
CloseURL();
}