linux c++ 实现http请求

#include HttpReq.h
#include <string.h>
int main(void)
{
HttpRequest* Http;
char http_return[4096] = {0};
char http_msg[4096] = {0};
strcpy(http_msg, "http://目标主机的IP和要发送的请求信息");

if(Http->HttpGet(http_msg, http_return)){
std::cout << http_return << std::endl;
}
return 0;
}

//
// Created by thinker on 7/6/16.
//

#ifndef PROJECT_HTTPREQ_H
#define PROJECT_HTTPREQ_H

#endif //PROJECT_HTTPREQ_H

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>

#define BUFSIZE 41000
#define URLSIZE 1024
#define INVALID_SOCKET -1
#define __DEBUG__

class HttpRequest
{
public:
HttpRequest();
~HttpRequest();
void DebugOut(const char *fmt, ...);

int HttpGet(const char* strUrl, char* strResponse);
int HttpPost(const char* strUrl, const char* strData, char* strResponse);

private:
int   HttpRequestExec(const char* strMethod, const char* strUrl, const char* strData, char* strResponse);
char* HttpHeadCreate(const char* strMethod, const char* strUrl, const char* strData);
char* HttpDataTransmit(char *strHttpHead, const int iSockFd);

int   GetPortFromUrl(const char* strUrl);
char* GetIPFromUrl(const char* strUrl);
char* GetParamFromUrl(const char* strUrl);
char* GetHostAddrFromUrl(const char* strUrl);

int   SocketFdCheck(const int iSockFd);

static int m_iSocketFd;
};

int HttpRequest::HttpGet(const char* strUrl, char* strResponse)
{
return HttpRequestExec("GET", strUrl, NULL, strResponse);
}

/**
*   功能描述：HttpPost请求
*   参数说明：
*               strUrl：     Http请求URL
*               strData：    POST请求发送的数据
*               strResponse：Http请求响应
*   返 回 值：
*               1表示成功
*               0表示失败
**/
int HttpRequest::HttpPost(const char* strUrl, const char* strData, char* strResponse)
{
return HttpRequestExec("POST", strUrl, strData, strResponse);
}

//执行HTTP请求，GET或POST
int HttpRequest::HttpRequestExec(const char* strMethod, const char* strUrl, const char* strData, char* strResponse)
{
//判断URL是否有效
if((strUrl == NULL) || (0 == strcmp(strUrl, ""))) {
DebugOut("%s %s %d\tURL为空\n", __FILE__, __FUNCTION__, __LINE__);
return 0;
}

//限制URL长度
if(URLSIZE < strlen(strUrl)) {
DebugOut("%s %s %d\tURL的长度不能超过%d\n", __FILE__, __FUNCTION__, __LINE__, URLSIZE);
return 0;
}

//创建HTTP协议头
char* strHttpHead = HttpHeadCreate(strMethod, strUrl, strData);

//判断套接字m_iSocketFd是否有效，有效就直接发送数据
if(m_iSocketFd != INVALID_SOCKET) {
//检查SocketFd是否为可写不可读状态
if(SocketFdCheck(m_iSocketFd) > 0) {
char* strResult = HttpDataTransmit(strHttpHead, m_iSocketFd);
if(NULL != strResult) {
strcpy(strResponse, strResult);
return 1;
}
}
}

//Create socket
m_iSocketFd = INVALID_SOCKET;
m_iSocketFd = socket(AF_INET, SOCK_STREAM, 0);
if (m_iSocketFd < 0 ) {
DebugOut("%s %s %d\tsocket error! Error code: %d，Error message: %s\n", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
return 0;
}

//Bind address and port
int iPort = GetPortFromUrl(strUrl);
if(iPort < 0) {
DebugOut("%s %s %d\t从URL获取端口失败\n", __FILE__, __FUNCTION__, __LINE__);
return 0;
}
char* strIP = GetIPFromUrl(strUrl);
if(strIP == NULL) {
DebugOut("%s %s %d\t从URL获取IP地址失败\n", __FILE__, __FUNCTION__, __LINE__);
return 0;
}
struct sockaddr_in servaddr;
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(iPort);
if (inet_pton(AF_INET, strIP, &servaddr.sin_addr) <= 0 ) {
DebugOut("%s %s %d\tinet_pton error! Error code: %d，Error message: %s\n", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
close(m_iSocketFd);
m_iSocketFd = INVALID_SOCKET;
return 0;
}

//Set non-blocking
int flags = fcntl(m_iSocketFd, F_GETFL, 0);
if(fcntl(m_iSocketFd, F_SETFL, flags|O_NONBLOCK) == -1) {
close(m_iSocketFd);
m_iSocketFd = INVALID_SOCKET;
DebugOut("%s %s %d\tfcntl error! Error code: %d，Error message: %s\n", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
return 0;
}

//非阻塞方式连接
int iRet = connect(m_iSocketFd, (struct sockaddr *)&servaddr, sizeof(servaddr));
if(iRet == 0) {
char* strResult = HttpDataTransmit(strHttpHead, m_iSocketFd);
if(NULL != strResult) {
strcpy(strResponse, strResult);
free(strResult);
return 1;
} else {
close(m_iSocketFd);
m_iSocketFd = INVALID_SOCKET;
free(strResult);
return 0;
}
}
else if(iRet < 0) {
if(errno != EINPROGRESS) {
return 0;
}
}

iRet = SocketFdCheck(m_iSocketFd);
if(iRet > 0) {
char* strResult = HttpDataTransmit(strHttpHead, m_iSocketFd);
if(NULL == strResult) {
close(m_iSocketFd);
m_iSocketFd = INVALID_SOCKET;
return 0;
}
else {
strcpy(strResponse, strResult);
free(strResult);
return 1;
}
}
else {
close(m_iSocketFd);
m_iSocketFd = INVALID_SOCKET;
return 0;
}

return 1;
}

//构建HTTP消息头
char* HttpRequest::HttpHeadCreate(const char* strMethod, const char* strUrl, const char* strData)
{
char* strHost = GetHostAddrFromUrl(strUrl);
char* strParam = GetParamFromUrl(strUrl);

char* strHttpHead = (char*)malloc(BUFSIZE);
memset(strHttpHead, 0, BUFSIZE);

strcat(strHttpHead, strMethod);
strcat(strHttpHead, " /");
strcat(strHttpHead, strParam);
free(strParam);
strcat(strHttpHead, " HTTP/1.1\r\n");
strcat(strHttpHead, "Accept: */*\r\n");
strcat(strHttpHead, "Accept-Language: cn\r\n");
strcat(strHttpHead, "User-Agent: Mozilla/4.0\r\n");
strcat(strHttpHead, "Host: ");
strcat(strHttpHead, strHost);
strcat(strHttpHead, "\r\n");
strcat(strHttpHead, "Cache-Control: no-cache\r\n");
strcat(strHttpHead, "Connection: Keep-Alive\r\n");
if(0 == strcmp(strMethod, "POST"))
{
char len[8] = {0};
unsigned uLen = strlen(strData);
sprintf(len, "%d", uLen);

strcat(strHttpHead, "Content-Type: application/x-www-form-urlencoded\r\n");
strcat(strHttpHead, "Content-Length: ");
strcat(strHttpHead, len);
strcat(strHttpHead, "\r\n\r\n");
strcat(strHttpHead, strData);
}
strcat(strHttpHead, "\r\n\r\n");

free(strHost);

return strHttpHead;
}

//发送HTTP请求并接受响应
char* HttpRequest::HttpDataTransmit(char *strHttpHead, const int iSockFd)
{
char* buf = (char*)malloc(BUFSIZE);
char* result=(char*)malloc(BUFSIZE);
memset(buf, 0, BUFSIZE);
int ret = send(iSockFd,(void *)strHttpHead,strlen(strHttpHead)+1,0);
free(strHttpHead);
if (ret < 0) {
DebugOut("%s %s %d\tsend error! Error code: %d，Error message: %s\n", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
close(iSockFd);
return NULL;
}

while(1)
{
ret = recv(iSockFd, (void *)buf, BUFSIZE,0);
if (ret == 0) //连接关闭
{
close(iSockFd);
return result;
}
else if(ret > 0) {
sprintf(result,"%s%s",result,buf);
continue;

}
else if(ret < 0) //出错
{
if(errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN) {
continue;
}
else {
close(iSockFd);
return NULL;
}
}
}
}

//从HTTP请求URL中获取主机地址，网址或者点分十进制IP地址
char* HttpRequest::GetHostAddrFromUrl(const char* strUrl)
{
char url[URLSIZE] = {0};
strcpy(url, strUrl);

char* strAddr = strstr(url, "http://");//判断有没有http://
if(strAddr == NULL) {
strAddr = strstr(url, "https://");//判断有没有https://
if(strAddr != NULL) {
strAddr += 8;
}
} else {
strAddr += 7;
}

if(strAddr == NULL) {
strAddr = url;
}
int iLen = strlen(strAddr);
char* strHostAddr = (char*)malloc(iLen+1);
memset(strHostAddr, 0, iLen+1);
for(int i=0; i<iLen+1; i++) {
if(strAddr[i] == '/') {
break;
} else {
strHostAddr[i] = strAddr[i];
}
}

return strHostAddr;
}

//从HTTP请求URL中获取HTTP请参数
char* HttpRequest::GetParamFromUrl(const char* strUrl)
{
char url[URLSIZE] = {0};
strcpy(url, strUrl);

char* strAddr = strstr(url, "http://");//判断有没有http://
if(strAddr == NULL) {
strAddr = strstr(url, "https://");//判断有没有https://
if(strAddr != NULL) {
strAddr += 8;
}
} else {
strAddr += 7;
}

if(strAddr == NULL) {
strAddr = url;
}
int iLen = strlen(strAddr);
char* strParam = (char*)malloc(iLen+1);
memset(strParam, 0, iLen+1);
int iPos = -1;
for(int i=0; i<iLen+1; i++) {
if(strAddr[i] == '/') {
iPos = i;
break;
}
}
if(iPos == -1) {
strcpy(strParam, "");;
} else {
strcpy(strParam, strAddr+iPos+1);
}
return strParam;
}

//从HTTP请求URL中获取端口号
int HttpRequest::GetPortFromUrl(const char* strUrl)
{
int iPort = -1;
char* strHostAddr = GetHostAddrFromUrl(strUrl);
if(strHostAddr == NULL) {
return -1;
}

char strAddr[URLSIZE] = {0};
strcpy(strAddr, strHostAddr);
free(strHostAddr);

char* strPort = strchr(strAddr, ':');
if(strPort == NULL) {
iPort = 80;
} else {
iPort = atoi(++strPort);
}
return iPort;
}

//从HTTP请求URL中获取IP地址
char* HttpRequest::GetIPFromUrl(const char* strUrl)
{
char* strHostAddr = GetHostAddrFromUrl(strUrl);
int iLen = strlen(strHostAddr);
char* strAddr = (char*)malloc(iLen+1);
memset(strAddr, 0, iLen+1);
int iCount = 0;
int iFlag = 0;
for(int i=0; i<iLen+1; i++) {
if(strHostAddr[i] == ':') {
break;
}

strAddr[i] = strHostAddr[i];
if(strHostAddr[i] == '.') {
iCount++;
continue;
}
if(iFlag == 1) {
continue;
}

if((strHostAddr[i] >= '0') || (strHostAddr[i] <= '9')) {
iFlag = 0;
} else {
iFlag = 1;
}
}
free(strHostAddr);

if(strlen(strAddr) <= 1) {
return NULL;
}

//判断是否为点分十进制IP地址，否则通过域名地址获取IP地址
if((iCount == 3) && (iFlag == 0)) {
return strAddr;
} else {
struct hostent *he = gethostbyname(strAddr);
free(strAddr);
if (he == NULL) {
return NULL;
} else {
struct in_addr** addr_list = (struct in_addr **)he->h_addr_list;
for(int i = 0; addr_list[i] != NULL; i++) {
return inet_ntoa(*addr_list[i]);
}
return NULL;
}
}
}

//检查SocketFd是否为可写不可读状态
int HttpRequest::SocketFdCheck(const int iSockFd)
{
struct timeval timeout ;
fd_set rset,wset;
FD_ZERO(&rset);
FD_ZERO(&wset);
FD_SET(iSockFd, &rset);
FD_SET(iSockFd, &wset);
timeout.tv_sec = 3;
timeout.tv_usec = 500;
int iRet = select(iSockFd+1, &rset, &wset, NULL, &timeout);
if(iRet > 0)
{
//判断SocketFd是否为可写不可读状态
int iW = FD_ISSET(iSockFd,&wset);
int iR = FD_ISSET(iSockFd,&rset);
if(iW && !iR)
{
char error[4] = "";
socklen_t len = sizeof(error);
int ret = getsockopt(iSockFd,SOL_SOCKET,SO_ERROR,error,&len);
if(ret == 0)
{
if(!strcmp(error, ""))
{
return iRet;//表示已经准备好的描述符数
}
else
{
DebugOut("%s %s %d\tgetsockopt error code:%d,error message:%s", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
}
}
else
{
DebugOut("%s %s %d\tgetsockopt failed. error code:%d,error message:%s", __FILE__, __FUNCTION__, __LINE__, errno, strerror(errno));
}
}
else
{
DebugOut("%s %s %d\tsockFd是否在可写字符集中：%d，是否在可读字符集中：%d\t(0表示不在)\n", __FILE__, __FUNCTION__, __LINE__, iW, iR);
}
}
else if(iRet == 0)
{
return 0;//表示超时
}
else
{
return -1;//select出错，所有描述符集清0
}
return -2;//其他错误
}

//打印输出
void HttpRequest::DebugOut(const char *fmt, ...)
{
#ifdef __DEBUG__
va_list ap;
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
#endif
}

int HttpRequest::m_iSocketFd = INVALID_SOCKET;