HTTP协议定义Web客户端如何从Web服务器请求Web页面，以及服务器如何把Web页面传送给客户端。HTTP协议采用了请求/响应模型。客户端向服务器发送一个请求报文，请求报文包含请求的方法、URL、协议版本、请求头部和请求数据。服务器以一个状态行作为响应，响应的内容包括协议的版本、成功或者错误代码、服务器信息、响应头部和响应数据。
一次http请求之后，http协议1.1版本不会直接就断开了，而是等几秒钟，等着用户有后续的操作，如果用户在这几秒钟之内有新的请求，那么还是通过之前的连接通道来收发消息，如果过了这几秒钟用户没有发送新的请求，那么就会断开连接，这样可以提高效率，减少短时间内建立连接的次数，因为建立连接也是耗时的，默认的好像是3秒中现在，但是这个时间是可以通过咱们后端的代码来调整的，自己网站根据自己网站用户的行为来分析统计出一个最优的等待时间。
GET与POST方法区别：
状态代码的第一个数字代表当前响应的类型：
超文本传输协议（HTTP）的统一资源定位符将从因特网获取信息的五个基本元素包括在一个简单的地址中：
例子：
以http://www.luffycity.com:80/news/index.html?id=250&page=1 为例, 其中：
http，是协议；
www.luffycity.com，是服务器
80，是服务器上的默认网络端口号
?id=250&page=1，是查询数据
找了一个基于TCP协议，实现HTTP传输的code，修改一下生成一个测试demo：
my_tcpclient.c
#include "my_tcpclient.h"
int main(){
my_tcpclient client;
int flags = 1;
char *response = NULL;
printf("开始组包\n");
while(flags){
my_tcpclient_create(&client,"10.100.10.24",18080);
if(http_post(&client,"/esim-lpa-server/lpa/polling?","data=89086030202200000019000037012045",&response)){
printf("失败!\n");
exit(2);
}
printf("响应:\n%d:%s\n",strlen(response),response);
flags = 0;
}
free(response);
return 0;
}
my_tcpclient.h
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define __DEBUG
#ifdef __DEBUG
#define DEBUG(...) printf(__VA_ARGS__)
#else
#define DEBUG(...)
#endif
#define BUFFER_SIZE 1024
/*
@socket
@remote_port
@remote_ip
@sockaddr_in
@connected flag
*/
typedef struct _my_tcpclient{
int socket;
int remote_port;
char remote_ip[16];
struct sockaddr_in _addr;
int connected;
} my_tcpclient;
int my_tcpclient_create(my_tcpclient *pclient,const char *host, int port);
int my_tcpclient_conn(my_tcpclient *pclient);
int my_tcpclient_recv(my_tcpclient *pclient,char **lpbuff,int size);
int my_tcpclient_send(my_tcpclient *pclient,char *buff,int size);
int my_tcpclient_close(my_tcpclient *pclient);
int my_http_post(my_tcpclient *pclient,char *page,char *request,char **response);
int my_tcpclient_create(my_tcpclient *pclient,const char *host, int port){
struct hostent *he;
if(pclient == NULL)
return -1;
memset(pclient,0,sizeof(my_tcpclient));
if((he = gethostbyname(host))==NULL){
return -2;
}
pclient->remote_port = port;
strcpy(pclient->remote_ip,inet_ntoa( *((struct in_addr *)he->h_addr) ));
pclient->_addr.sin_family = AF_INET;
pclient->_addr.sin_port = htons(pclient->remote_port);
pclient->_addr.sin_addr = *((struct in_addr *)he->h_addr);
if((pclient->socket = socket(AF_INET,SOCK_STREAM,0))==-1){
return -3;
}
return 0;
}
int my_tcpclient_conn(my_tcpclient *pclient){
if(pclient->connected)
return 1;
if(connect(pclient->socket, (struct sockaddr *)&pclient->_addr,sizeof(struct sockaddr))==-1){
return -1;
}
pclient->connected = 1;
return 0;
}
int my_tcpclient_recv(my_tcpclient *pclient,char **lpbuff,int size){
int recvnum=0,tmpres=0;
char buff[BUFFER_SIZE];
*lpbuff = NULL;
while(recvnum < size || size==0){
tmpres = recv(pclient->socket, buff,BUFFER_SIZE,0);
if(tmpres <= 0)
break;
recvnum += tmpres;
if(*lpbuff == NULL){
*lpbuff = (char*)malloc(recvnum);
if(*lpbuff == NULL)
return -2;
}else{
*lpbuff = (char*)realloc(*lpbuff,recvnum);
if(*lpbuff == NULL)
return -2;
}
memcpy(*lpbuff+recvnum-tmpres,buff,tmpres);
}
return recvnum;
}
int my_tcpclient_send(my_tcpclient *pclient,char *buff,int size){
int sent=0,tmpres=0;
while(sent < size){
tmpres = send(pclient->socket,buff+sent,size-sent,0);
if(tmpres == -1){
return -1;
}
sent += tmpres;
}
return sent;
}
int my_tcpclient_close(my_tcpclient *pclient){
close(pclient->socket);
pclient->connected = 0;
}
void get_http_header(char *header){
char userAgent[] = "User-Agent: QG1 Http 0.1\r\n";
char cacheCtrl[] = "Cache-Control: no-cache\r\n";
char contentType[] = "Content-Type: application/x-www-form-urlencoded\r\n";
char postmanToken[] = "Postman-Token: 8d4d5783-4660-c219-8644-e2e7dad68500\r\n";
char auth[] = "Authorization: Basic cm9hbTJmcmVlOmx5bmttYXhfdGVzdA==\r\n";
char accept[] = "Accept: */*\r\n";
strcpy(header,userAgent);
strcat(header,cacheCtrl);
strcat(header,contentType);
strcat(header,postmanToken);
strcat(header,auth);
strcat(header,accept);
}
int http_post(my_tcpclient *pclient,char *page,char *request,char **response){
char post[300],host[100],content_len[100];
char *lpbuf,*ptmp;
int len=0;
char header2[1024];
memset(header2, sizeof(header2), 0);
get_http_header(header2);
//DEBUG("header2 : %s \n", header2);
lpbuf = NULL;
sprintf(post,"POST %s HTTP/1.0\r\n",page);
sprintf(host,"HOST: %s:%d\r\n",pclient->remote_ip,pclient->remote_port);
sprintf(content_len,"Content-Length: %d\r\n\r\n",strlen(request));
len = strlen(post)+strlen(host)+strlen(header2)+strlen(content_len)+strlen(request)+1;
lpbuf = (char*)malloc(len);
if(lpbuf==NULL){
return -1;
}
strcpy(lpbuf,post);
strcat(lpbuf,host);
strcat(lpbuf,header2);
strcat(lpbuf,content_len);
strcat(lpbuf,request);
//printf("liuyan: http data= \r\n%s liuyan end \n", lpbuf);
if(!pclient->connected){
my_tcpclient_conn(pclient);
}
if(my_tcpclient_send(pclient,lpbuf,len)<0){
return -1;
}
printf("发送请求:\n%s\n",lpbuf);
/*释放内存*/
if(lpbuf != NULL)
free(lpbuf);
lpbuf = NULL;
/*it's time to recv from server*/
if(my_tcpclient_recv(pclient,&lpbuf,0) <= 0){
if(lpbuf)
free(lpbuf);
return -2;
}
printf("接收响应:\n%s\n",lpbuf);
/*响应代码,|HTTP/1.0 200 OK|
*从第10个字符开始,第3位
* */
memset(post,0,sizeof(post));
strncpy(post,lpbuf+9,3);
if(atoi(post)!=200){
if(lpbuf) free(lpbuf);
return atoi(post);
}
ptmp = (char*)strstr(lpbuf,"\r\n\r\n");
if(ptmp == NULL){
free(lpbuf);
return -3;
}
ptmp += 4;/*跳过\r\n*/
len = strlen(ptmp)+1;
*response=(char*)malloc(len);
if(*response == NULL){
if(lpbuf) free(lpbuf);
return -1;
}
memset(*response,0,len);
memcpy(*response,ptmp,len-1);
/*从头域找到内容长度,如果没有找到则不处理*/
ptmp = (char*)strstr(lpbuf,"Content-Length:");
if(ptmp != NULL){
char *ptmp2;
ptmp += 15;
ptmp2 = (char*)strstr(ptmp,"\r\n");
if(ptmp2 != NULL){
memset(post,0,sizeof(post));
strncpy(post,ptmp,ptmp2-ptmp);
if(atoi(post)<len)
(*response)[atoi(post)] = '\0';
}
}
if(lpbuf) free(lpbuf);
return 0;
}
使用TCP传输的打印结果
发送数据/接收数据：