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1 使用的知识点

2 http请求

get 和 post的区别

http协议请求报文格式:
1 请求行 GET /test.txt HTTP/1.1
2 请求行 健值对
3 空行 \r\n
4 数据

http协议响应消息格式:
1 状态行 200 表示成功, 404 表示请求的资源不存在
2 消息报头 健值对
3 空行 \r\n
4 响应正文

3 整体功能介绍

4 基于epoll的web服务器开发流程

1. 创建socket，得到监听文件描述符lfd——socket

2. 设置端口复用——setsockopt()

3. 绑定——bind（）

4. 设置监听——listen（）

5. 创建epoll树，得到树根描述符epfd——epoll_create()

6. 将监听文件描述符lfd上树——epoll_ctr(epfd,epoll_CTL_ADD…)\

7. while(1)
   {
   // 等待事件发生
   nread = epoll_wait();
   if(nread < 0)
   {
   if(errno == EINTR)
   {
   continue;
   }
   break;
   }

   // 下面是有事件发生，循环处理没一个文件描述符
   for(i = 0; i<nready;i++)
   {
   sockfd = event[i].data.fd;
   // 有客户端连接请求到来
   if(sockfd = lfd)
   {
   cfd = accept();
   // 将新的cfd 上树
   epoll_ctl(epfd, EPOLL_CTL_ADD…);

    }// 有数据发来的情况else{// 接受数据并进行处理http_request();}
   

   }
   }
   

int http_request(inf cfd)
{
// 读取请求行
Readline();
// 分析请求行，得到要请求的资源文件夹file
如 GET/hanzi.c /HTTP1.1
// 循环读完剩余的内核缓冲区的数据
while((n = Readline())>0);
// 判断文件是否存在
stat();
1. 文件不存在
返回错误页
组织应答消息： http响应格式消息 + 错误页正文内容
2. 文件存在
判断文件类型
2.1 普通文件
组织应答信息: http响应格式信息+消息正文
2.2 目录文件
组织应答消息： http响应格式消息 + html格式文件内容

}

5 服务器代码

//web服务端程序--使用epoll模型
#include <unistd.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <string.h>
#include <signal.h>
#include <dirent.h>#include "pub.h"
#include "wrap.h"int http_request(int cfd, int epfd);int main()
{//若web服务器给浏览器发送数据的时候, 浏览器已经关闭连接, //则web服务器就会收到SIGPIPE信号struct sigaction act;act.sa_handler = SIG_IGN;sigemptyset(&act.sa_mask);act.sa_flags = 0;sigaction(SIGPIPE, &act, NULL);//改变当前进程的工作目录char path[255] = {0};sprintf(path, "%s/%s", getenv("HOME"), "webpath");chdir(path);//创建socket--设置端口复用---bindint lfd = tcp4bind(9999, NULL);//设置监听Listen(lfd, 128);//创建epoll树int epfd = epoll_create(1024);if(epfd<0){perror("epoll_create error");close(lfd);return -1;}//将监听文件描述符lfd上树struct epoll_event ev;ev.data.fd = lfd;ev.events = EPOLLIN;epoll_ctl(epfd, EPOLL_CTL_ADD, lfd, &ev);int i;int cfd;int nready;int sockfd;struct epoll_event events[1024];while(1){//等待事件发生nready = epoll_wait(epfd, events, 1024, -1);if(nready<0){if(errno==EINTR){continue;}break;}for(i=0; i<nready; i++){sockfd = events[i].data.fd;//有客户端连接请求if(sockfd==lfd){//接受新的客户端连接cfd = Accept(lfd, NULL, NULL);//设置cfd为非阻塞int flag = fcntl(cfd, F_GETFL);flag |= O_NONBLOCK;fcntl(cfd, F_SETFL, flag);//将新的cfd上树ev.data.fd = cfd;ev.events = EPOLLIN;epoll_ctl(epfd, EPOLL_CTL_ADD, cfd, &ev);}else {//有客户端数据发来http_request(sockfd, epfd);}			}		}
}int send_header(int cfd, char *code, char *msg, char *fileType, int len)
{char buf[1024] = {0};sprintf(buf, "HTTP/1.1 %s %s\r\n", code, msg);sprintf(buf+strlen(buf), "Content-Type:%s\r\n", fileType);if(len>0){sprintf(buf+strlen(buf), "Content-Length:%d\r\n", len);}strcat(buf, "\r\n");Write(cfd, buf, strlen(buf));return 0;
}int send_file(int cfd, char *fileName)
{//打开文件int fd = open(fileName, O_RDONLY);if(fd<0){perror("open error");return -1;}//循环读文件, 然后发送int n;char buf[1024];while(1){memset(buf, 0x00, sizeof(buf));n = read(fd, buf, sizeof(buf));if(n<=0){break;}else {Write(cfd, buf, n);}}
}int http_request(int cfd, int epfd)
{int n;char buf[1024];//读取请求行数据, 分析出要请求的资源文件名memset(buf, 0x00, sizeof(buf));n = Readline(cfd, buf, sizeof(buf));if(n<=0){//printf("read error or client closed, n==[%d]\n", n);//关闭连接close(cfd);//将文件描述符从epoll树上删除epoll_ctl(epfd, EPOLL_CTL_DEL, cfd, NULL);return -1;	}printf("buf==[%s]\n", buf);//GET /hanzi.c HTTP/1.1char reqType[16] = {0};char fileName[255] = {0};char protocal[16] = {0};sscanf(buf, "%[^ ] %[^ ] %[^ \r\n]", reqType, fileName, protocal);//printf("[%s]\n", reqType);printf("--[%s]--\n", fileName);//printf("[%s]\n", protocal);char *pFile = fileName;if(strlen(fileName)<=1){strcpy(pFile, "./");}else {pFile = fileName+1;}//转换汉字编码strdecode(pFile, pFile);printf("[%s]\n", pFile);//循环读取完剩余的数据,避免产生粘包while((n=Readline(cfd, buf, sizeof(buf)))>0);//判断文件是否存在struct stat st;if(stat(pFile, &st)<0){printf("file not exist\n");//发送头部信息send_header(cfd, "404", "NOT FOUND", get_mime_type(".html"), 0);//发送文件内容send_file(cfd, "error.html");	}else //若文件存在{//判断文件类型//普通文件if(S_ISREG(st.st_mode)){printf("file exist\n");//发送头部信息send_header(cfd, "200", "OK", get_mime_type(pFile), st.st_size);//发送文件内容send_file(cfd, pFile);}//目录文件else if(S_ISDIR(st.st_mode)){printf("目录文件\n");char buffer[1024];//发送头部信息send_header(cfd, "200", "OK", get_mime_type(".html"), 0);	//发送html文件头部send_file(cfd, "html/dir_header.html");	//文件列表信息struct dirent **namelist;int num;num = scandir(pFile, &namelist, NULL, alphasort);if (num < 0){perror("scandir");close(cfd);epoll_ctl(epfd, EPOLL_CTL_DEL, cfd, NULL);return -1;}else {while (num--) {printf("%s\n", namelist[num]->d_name);memset(buffer, 0x00, sizeof(buffer));if(namelist[num]->d_type==DT_DIR){sprintf(buffer, "<li><a href=%s/>%s</a></li>", namelist[num]->d_name, namelist[num]->d_name);}else{sprintf(buffer, "<li><a href=%s>%s</a></li>", namelist[num]->d_name, namelist[num]->d_name);}free(namelist[num]);Write(cfd, buffer, strlen(buffer));}free(namelist);}//发送html尾部sleep(10);send_file(cfd, "html/dir_tail.html");		}}return 0;
}

6 libevent版本的本地web服务器

//通过libevent编写的web服务器
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include "pub.h"
#include <event.h>
#include <event2/listener.h>
#include <dirent.h>#define _WORK_DIR_ "%s/webpath"
#define _DIR_PREFIX_FILE_ "html/dir_header.html"
#define _DIR_TAIL_FILE_ "html/dir_tail.html"int copy_header(struct bufferevent *bev,int op,char *msg,char *filetype,long filesize)
{char buf[4096]={0};sprintf(buf,"HTTP/1.1 %d %s\r\n",op,msg);sprintf(buf,"%sContent-Type: %s\r\n",buf,filetype);if(filesize >= 0){sprintf(buf,"%sContent-Length:%ld\r\n",buf,filesize);}strcat(buf,"\r\n");bufferevent_write(bev,buf,strlen(buf));return 0;
}
int copy_file(struct bufferevent *bev,const char *strFile)
{int fd = open(strFile,O_RDONLY);char buf[1024]={0};int ret;while( (ret = read(fd,buf,sizeof(buf))) > 0 ){bufferevent_write(bev,buf,ret);}close(fd);return 0;
}
//发送目录，实际上组织一个html页面发给客户端，目录的内容作为列表显示
int send_dir(struct bufferevent *bev,const char *strPath)
{//需要拼出来一个html页面发送给客户端copy_file(bev,_DIR_PREFIX_FILE_);//send dir info DIR *dir = opendir(strPath);if(dir == NULL){perror("opendir err");return -1;}char bufline[1024]={0};struct dirent *dent = NULL;while( (dent= readdir(dir) ) ){struct stat sb;stat(dent->d_name,&sb);if(dent->d_type == DT_DIR){//目录文件 特殊处理//格式 <a href="dirname/">dirname</a><p>size</p><p>time</p></br>memset(bufline,0x00,sizeof(bufline));sprintf(bufline,"<li><a href='%s/'>%32s</a>   %8ld</li>",dent->d_name,dent->d_name,sb.st_size);bufferevent_write(bev,bufline,strlen(bufline));}else if(dent->d_type == DT_REG){//普通文件 直接显示列表即可memset(bufline,0x00,sizeof(bufline));sprintf(bufline,"<li><a href='%s'>%32s</a>     %8ld</li>",dent->d_name,dent->d_name,sb.st_size);bufferevent_write(bev,bufline,strlen(bufline));}}closedir(dir);copy_file(bev,_DIR_TAIL_FILE_);//bufferevent_free(bev);return 0;
}
int http_request(struct bufferevent *bev,char *path)
{strdecode(path, path);//将中文问题转码成utf-8格式的字符串char *strPath = path;if(strcmp(strPath,"/") == 0 || strcmp(strPath,"/.") == 0){strPath = "./";}else{strPath = path+1;}struct stat sb;if(stat(strPath,&sb) < 0){//不存在 ，给404页面copy_header(bev,404,"NOT FOUND",get_mime_type("error.html"),-1);copy_file(bev,"error.html");return -1;}if(S_ISDIR(sb.st_mode)){//处理目录copy_header(bev,200,"OK",get_mime_type("ww.html"),sb.st_size);send_dir(bev,strPath);}if(S_ISREG(sb.st_mode)){//处理文件//写头copy_header(bev,200,"OK",get_mime_type(strPath),sb.st_size);//写文件内容copy_file(bev,strPath);}return 0;
}void read_cb(struct bufferevent *bev, void *ctx)
{char buf[256]={0};char method[10],path[256],protocol[10];int ret = bufferevent_read(bev, buf, sizeof(buf));if(ret > 0){sscanf(buf,"%[^ ] %[^ ] %[^ \r\n]",method,path,protocol);if(strcasecmp(method,"get") == 0){//处理客户端的请求char bufline[256];write(STDOUT_FILENO,buf,ret);//确保数据读完while( (ret = bufferevent_read(bev, bufline, sizeof(bufline)) ) > 0){write(STDOUT_FILENO,bufline,ret);}http_request(bev,path);//处理请求}}
}
void bevent_cb(struct bufferevent *bev, short what, void *ctx)
{if(what & BEV_EVENT_EOF){//客户端关闭printf("client closed\n");bufferevent_free(bev);}else if(what & BEV_EVENT_ERROR){printf("err to client closed\n");bufferevent_free(bev);}else if(what & BEV_EVENT_CONNECTED){//连接成功printf("client connect ok\n");}
}
void listen_cb(struct evconnlistener *listener, evutil_socket_t fd, struct sockaddr *addr, int socklen, void *arg)
{//定义与客户端通信的buffereventstruct event_base *base = (struct event_base *)arg;struct bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);bufferevent_setcb(bev,read_cb,NULL,bevent_cb,base);//设置回调bufferevent_enable(bev,EV_READ|EV_WRITE);//启用读和写
}int main(int argc,char *argv[])
{char workdir[256] = {0};sprintf(workdir,_WORK_DIR_,getenv("HOME"));//HOME=/home/itheima chdir(workdir);struct event_base *base = event_base_new();//创建根节点struct sockaddr_in serv;serv.sin_family = AF_INET;serv.sin_port = htons(9999);serv.sin_addr.s_addr = htonl(INADDR_ANY);struct evconnlistener * listener =evconnlistener_new_bind(base,listen_cb, base, LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1,(struct sockaddr *)&serv, sizeof(serv));//连接监听器event_base_dispatch(base);//循环event_base_free(base); //释放根节点evconnlistener_free(listener);//释放链接监听器return 0;
}