[Linux网络编程]10-http协议，分别使用epoll和libevent两种方式实现B/S服务器

一.HTTP协议，Request请求和Response响应

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二.常用状态码

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接下来使用两种方式构建B/S模型,实现浏览器向客户端请求文件的功能。
浏览器向构建好的服务器发送请求，在请求行中请求具体文件，服务器连通客户端(浏览器)后，检查文件是否存在，如果文件存在，向浏览器回发response，并回发文件。

实现流程：
1.服务器监听lfd，读端有数据代表有客户端连接，接受请求，并将新socket加入监听
2.新socket有读事件发生，即客户端(浏览器)发送了数据，即浏览器向服务器发送了请求行，请求头等
3.服务器解析浏览器发送的请求信息，拆分字符串获取GET/POST请求，获取其请求的文件信息等。
4.服务器利用stat检查文件是否存在，不存在返回错误页面，存在则进一步判断是目录还是文件。
5.若是目录，服务器先回发response，Content-Type指定为html(Content-Type指定了浏览器以何种方式解析内容)，再搭建一个html页面，将目录中的目录项封装成超链接，回传浏览器。
若是文件，服务器先利用get_filetype方法获取文件类型，再封装Content-Type，回发respnse和文件。
6.当url有中文时，浏览器以unicode表示，应进行编码和解码操作，浏览器发数据给服务器时进行解码，服务器回发时应该编码。

三.epoll服务器模型实现B/S架构

main.c

int main(int argc, const char* argv[])
{if (argc < 3){printf("eg: ./a.out port path\n");exit(1);}// 采用指定的端口int port = atoi(argv[1]);// 修改进程工作目录, 方便后续操作int ret = chdir(argv[2]);if (ret == -1){perror("chdir error");exit(1);}// 启动epoll模型 epoll_run(port);return 0;
}

epoll_http.c

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <sys/epoll.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/stat.h>
#include <ctype.h>
#include "epoll_server.h"#define MAXSIZE 2000void send_error(int cfd, int status, char *title, char *text)
{char buf[4096] = {0};sprintf(buf, "%s %d %s\r\n", "HTTP/1.1", status, title);sprintf(buf+strlen(buf), "Content-Type:%s\r\n", "text/html");sprintf(buf+strlen(buf), "Content-Length:%d\r\n", -1);sprintf(buf+strlen(buf), "Connection: close\r\n");send(cfd, buf, strlen(buf), 0);send(cfd, "\r\n", 2, 0);memset(buf, 0, sizeof(buf));sprintf(buf, "<html><head><title>%d %s</title></head>\n", status, title);sprintf(buf+strlen(buf), "<body bgcolor=\"#cc99cc\"><h2 align=\"center\">%d %s</h4>\n", status, title);sprintf(buf+strlen(buf), "%s\n", text);sprintf(buf+strlen(buf), "<hr>\n</body>\n</html>\n");send(cfd, buf, strlen(buf), 0);return ;
}void epoll_run(int port)
{int i = 0;// 创建一个epoll树的根节点int epfd = epoll_create(MAXSIZE);if(epfd == -1) {   perror("epoll_create error");exit(1);}// 添加要监听的节点// 先添加监听lfdint lfd = init_listen_fd(port, epfd);// 委托内核检测添加到树上的节点struct epoll_event all[MAXSIZE];while(1) {int ret = epoll_wait(epfd, all, MAXSIZE, 0);if(ret == -1) {perror("epoll_wait error");exit(1);}// 遍历发生变化的节点for(i=0; i<ret; ++i){// 只处理读事件, 其他事件默认不处理struct epoll_event *pev = &all[i];if(!(pev->events & EPOLLIN)) {// 不是读事件continue;}if(pev->data.fd == lfd){// 接受连接请求do_accept(lfd, epfd);} else {// 读数据printf("======================before do read, ret = %d\n", ret);do_read(pev->data.fd, epfd);printf("=========================================after do read\n");}}}
}// 读数据
void do_read(int cfd, int epfd)
{// 将浏览器发过来的数据, 读到buf中 char line[1024] = {0};// 读请求行int len = get_line(cfd, line, sizeof(line));if(len == 0) {   printf("客户端断开了连接...\n");// 关闭套接字, cfd从epoll上deldisconnect(cfd, epfd);         } else { printf("============= 请求头 ============\n");   printf("请求行数据: %s", line);// 还有数据没读完,继续读走while (1) {char buf[1024] = {0};len = get_line(cfd, buf, sizeof(buf));	if (buf[0] == '\n') {break;	} else if (len == -1)break;}printf("============= The End ============\n");}// 判断get请求if(strncasecmp("get", line, 3) == 0) { // 请求行: get /hello.c http/1.1   // 处理http请求http_request(line, cfd);// 关闭套接字, cfd从epoll上deldisconnect(cfd, epfd);         }
}// 断开连接的函数
void disconnect(int cfd, int epfd)
{int ret = epoll_ctl(epfd, EPOLL_CTL_DEL, cfd, NULL);if(ret == -1) {   perror("epoll_ctl del cfd error");exit(1);}close(cfd);
}// http请求处理
void http_request(const char* request, int cfd)
{// 拆分http请求行char method[12], path[1024], protocol[12];sscanf(request, "%[^ ] %[^ ] %[^ ]", method, path, protocol);printf("method = %s, path = %s, protocol = %s\n", method, path, protocol);// 转码 将不能识别的中文乱码 -> 中文// 解码 %23 %34 %5fdecode_str(path, path);char* file = path+1; // 去掉path中的/ 获取访问文件名// 如果没有指定访问的资源, 默认显示资源目录中的内容if(strcmp(path, "/") == 0) {    // file的值, 资源目录的当前位置file = "./";}// 获取文件属性struct stat st;int ret = stat(file, &st);if(ret == -1) { send_error(cfd, 404, "Not Found", "NO such file or direntry");     return;}// 判断是目录还是文件if(S_ISDIR(st.st_mode)) {  		// 目录 // 发送头信息send_respond_head(cfd, 200, "OK", get_file_type(".html"), -1);// 发送目录信息send_dir(cfd, file);} else if(S_ISREG(st.st_mode)) { // 文件        // 发送消息报头send_respond_head(cfd, 200, "OK", get_file_type(file), st.st_size);// 发送文件内容send_file(cfd, file);}
}// 发送目录内容
void send_dir(int cfd, const char* dirname)
{int i, ret;// 拼一个html页面<table></table>char buf[4094] = {0};sprintf(buf, "<html><head><title>目录名: %s</title></head>", dirname);sprintf(buf+strlen(buf), "<body><h1>当前目录: %s</h1><table>", dirname);char enstr[1024] = {0};char path[1024] = {0};// 目录项二级指针struct dirent** ptr;int num = scandir(dirname, &ptr, NULL, alphasort);// 遍历for(i = 0; i < num; ++i) {char* name = ptr[i]->d_name;// 拼接文件的完整路径sprintf(path, "%s/%s", dirname, name);printf("path = %s ===================\n", path);struct stat st;stat(path, &st);// 编码生成 %E5 %A7 之类的东西encode_str(enstr, sizeof(enstr), name);// 如果是文件if(S_ISREG(st.st_mode)) {       sprintf(buf+strlen(buf), "<tr><td><a href=\"%s\">%s</a></td><td>%ld</td></tr>",enstr, name, (long)st.st_size);} else if(S_ISDIR(st.st_mode)) {		// 如果是目录       sprintf(buf+strlen(buf), "<tr><td><a href=\"%s/\">%s/</a></td><td>%ld</td></tr>",enstr, name, (long)st.st_size);}ret = send(cfd, buf, strlen(buf), 0);if (ret == -1) {if (errno == EAGAIN) {perror("send error:");continue;} else if (errno == EINTR) {perror("send error:");continue;} else {perror("send error:");exit(1);}}memset(buf, 0, sizeof(buf));// 字符串拼接}sprintf(buf+strlen(buf), "</table></body></html>");send(cfd, buf, strlen(buf), 0);printf("dir message send OK!!!!\n");
#if 0// 打开目录DIR* dir = opendir(dirname);if(dir == NULL){perror("opendir error");exit(1);}// 读目录struct dirent* ptr = NULL;while( (ptr = readdir(dir)) != NULL ){char* name = ptr->d_name;}closedir(dir);
#endif
}// 发送响应头
void send_respond_head(int cfd, int no, const char* desp, const char* type, long len)
{char buf[1024] = {0};// 状态行sprintf(buf, "http/1.1 %d %s\r\n", no, desp);send(cfd, buf, strlen(buf), 0);// 消息报头sprintf(buf, "Content-Type:%s\r\n", type);sprintf(buf+strlen(buf), "Content-Length:%ld\r\n", len);send(cfd, buf, strlen(buf), 0);// 空行send(cfd, "\r\n", 2, 0);
}// 发送文件
void send_file(int cfd, const char* filename)
{// 打开文件int fd = open(filename, O_RDONLY);if(fd == -1) {   send_error(cfd, 404, "Not Found", "NO such file or direntry");exit(1);}// 循环读文件char buf[4096] = {0};int len = 0, ret = 0;while( (len = read(fd, buf, sizeof(buf))) > 0 ) {   // 发送读出的数据ret = send(cfd, buf, len, 0);if (ret == -1) {if (errno == EAGAIN) {perror("send error:");continue;} else if (errno == EINTR) {perror("send error:");continue;} else {perror("send error:");exit(1);}}}if(len == -1)  {  perror("read file error");exit(1);}close(fd);
}// 解析http请求消息的每一行内容
int get_line(int sock, char *buf, int size)
{int i = 0;char c = '\0';int n;while ((i < size - 1) && (c != '\n')) {    n = recv(sock, &c, 1, 0);if (n > 0) {        if (c == '\r') {            n = recv(sock, &c, 1, MSG_PEEK);if ((n > 0) && (c == '\n')) {               recv(sock, &c, 1, 0);} else {                            c = '\n';}}buf[i] = c;i++;} else {       c = '\n';}}buf[i] = '\0';return i;
}// 接受新连接处理
void do_accept(int lfd, int epfd)
{struct sockaddr_in client;socklen_t len = sizeof(client);int cfd = accept(lfd, (struct sockaddr*)&client, &len);if(cfd == -1) {  perror("accept error");exit(1);}// 打印客户端信息char ip[64] = {0};printf("New Client IP: %s, Port: %d, cfd = %d\n",inet_ntop(AF_INET, &client.sin_addr.s_addr, ip, sizeof(ip)),ntohs(client.sin_port), cfd);// 设置cfd为非阻塞int flag = fcntl(cfd, F_GETFL);flag |= O_NONBLOCK;fcntl(cfd, F_SETFL, flag);// 得到的新节点挂到epoll树上struct epoll_event ev;ev.data.fd = cfd;// 边沿非阻塞模式ev.events = EPOLLIN | EPOLLET;int ret = epoll_ctl(epfd, EPOLL_CTL_ADD, cfd, &ev);if(ret == -1) { perror("epoll_ctl add cfd error");exit(1);}
}int init_listen_fd(int port, int epfd)
{//　创建监听的套接字int lfd = socket(AF_INET, SOCK_STREAM, 0);if(lfd == -1) {  perror("socket error");exit(1);}// lfd绑定本地IP和portstruct sockaddr_in serv;memset(&serv, 0, sizeof(serv));serv.sin_family = AF_INET;serv.sin_port = htons(port);serv.sin_addr.s_addr = htonl(INADDR_ANY);// 端口复用int flag = 1;setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag));int ret = bind(lfd, (struct sockaddr*)&serv, sizeof(serv));if(ret == -1) {    perror("bind error");exit(1);}// 设置监听ret = listen(lfd, 64);if(ret == -1) {    perror("listen error");exit(1);}// lfd添加到epoll树上struct epoll_event ev;ev.events = EPOLLIN;ev.data.fd = lfd;ret = epoll_ctl(epfd, EPOLL_CTL_ADD, lfd, &ev);if(ret == -1) {  perror("epoll_ctl add lfd error");exit(1);}return lfd;
}// 16进制数转化为10进制
int hexit(char c)
{if (c >= '0' && c <= '9')return c - '0';if (c >= 'a' && c <= 'f')return c - 'a' + 10;if (c >= 'A' && c <= 'F')return c - 'A' + 10;return 0;
}/**  这里的内容是处理%20之类的东西！是"解码"过程。*  %20 URL编码中的‘ ’(space)*  %21 '!' %22 '"' %23 '#' %24 '$'*  %25 '%' %26 '&' %27 ''' %28 '('......*  相关知识html中的‘ ’(space)是&nbsp*/
void encode_str(char* to, int tosize, const char* from)
{int tolen;for (tolen = 0; *from != '\0' && tolen + 4 < tosize; ++from) {    if (isalnum(*from) || strchr("/_.-~", *from) != (char*)0) {      *to = *from;++to;++tolen;} else {sprintf(to, "%%%02x", (int) *from & 0xff);to += 3;tolen += 3;}}*to = '\0';
}void decode_str(char *to, char *from)
{for ( ; *from != '\0'; ++to, ++from  ) {     if (from[0] == '%' && isxdigit(from[1]) && isxdigit(from[2])) {       *to = hexit(from[1])*16 + hexit(from[2]);from += 2;                      } else {*to = *from;}}*to = '\0';
}// 通过文件名获取文件的类型
const char *get_file_type(const char *name)
{char* dot;// 自右向左查找‘.’字符, 如不存在返回NULLdot = strrchr(name, '.');   if (dot == NULL)return "text/plain; charset=utf-8";if (strcmp(dot, ".html") == 0 || strcmp(dot, ".htm") == 0)return "text/html; charset=utf-8";if (strcmp(dot, ".jpg") == 0 || strcmp(dot, ".jpeg") == 0)return "image/jpeg";if (strcmp(dot, ".gif") == 0)return "image/gif";if (strcmp(dot, ".png") == 0)return "image/png";if (strcmp(dot, ".css") == 0)return "text/css";if (strcmp(dot, ".au") == 0)return "audio/basic";if (strcmp( dot, ".wav" ) == 0)return "audio/wav";if (strcmp(dot, ".avi") == 0)return "video/x-msvideo";if (strcmp(dot, ".mov") == 0 || strcmp(dot, ".qt") == 0)return "video/quicktime";if (strcmp(dot, ".mpeg") == 0 || strcmp(dot, ".mpe") == 0)return "video/mpeg";if (strcmp(dot, ".vrml") == 0 || strcmp(dot, ".wrl") == 0)return "model/vrml";if (strcmp(dot, ".midi") == 0 || strcmp(dot, ".mid") == 0)return "audio/midi";if (strcmp(dot, ".mp3") == 0)return "audio/mpeg";if (strcmp(dot, ".ogg") == 0)return "application/ogg";if (strcmp(dot, ".pac") == 0)return "application/x-ns-proxy-autoconfig";return "text/plain; charset=utf-8";
}

四.基于libevent实现B/S架构

main.c

#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <event2/bufferevent.h>
#include <event2/listener.h>
#include <event2/event.h>
#include "libevent_http.h"int main(int argc, char **argv)
{if(argc < 3){printf("./event_http port path\n");return -1;}if(chdir(argv[2]) < 0) {printf("dir is not exists: %s\n", argv[2]);perror("chdir err:");return -1;}struct event_base *base;struct evconnlistener *listener;struct event *signal_event;struct sockaddr_in sin;base = event_base_new();if (!base){fprintf(stderr, "Could not initialize libevent!\n");return 1;}memset(&sin, 0, sizeof(sin));sin.sin_family = AF_INET;sin.sin_port = htons(atoi(argv[1]));// 创建监听的套接字，绑定，监听，接受连接请求listener = evconnlistener_new_bind(base, listener_cb, (void *)base,LEV_OPT_REUSEABLE | LEV_OPT_CLOSE_ON_FREE, -1,(struct sockaddr*)&sin, sizeof(sin));if (!listener){fprintf(stderr, "Could not create a listener!\n");return 1;}// 创建信号事件, 捕捉并处理signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);if (!signal_event || event_add(signal_event, NULL)<0) {fprintf(stderr, "Could not create/add a signal event!\n");return 1;}// 事件循环event_base_dispatch(base);evconnlistener_free(listener);event_free(signal_event);event_base_free(base);printf("done\n");return 0;
}

libevent_http.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <string.h>
#include <dirent.h>
#include <time.h>
#include <signal.h>
#include <ctype.h>
#include <errno.h>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/listener.h>
#include "libevent_http.h"#define _HTTP_CLOSE_ "Connection: close\r\n"int response_http(struct bufferevent *bev, const char *method, char *path)
{if(strcasecmp("GET", method) == 0){//get method ...strdecode(path, path);char *pf = &path[1];if(strcmp(path, "/") == 0 || strcmp(path, "/.") == 0){pf="./";}printf("***** http Request Resource Path =  %s, pf = %s\n", path, pf);struct stat sb;if(stat(pf,&sb) < 0){perror("open file err:");send_error(bev);return -1;}if(S_ISDIR(sb.st_mode))//处理目录{//应该显示目录列表send_header(bev, 200, "OK", get_file_type(".html"), -1);send_dir(bev, pf);}else //处理文件{send_header(bev, 200, "OK", get_file_type(pf), sb.st_size);send_file_to_http(pf, bev);}}return 0;
}/**charset=iso-8859-1	西欧的编码，说明网站采用的编码是英文；*charset=gb2312		说明网站采用的编码是简体中文；*charset=utf-8			代表世界通用的语言编码；*						可以用到中文、韩文、日文等世界上所有语言编码上*charset=euc-kr		说明网站采用的编码是韩文；*charset=big5			说明网站采用的编码是繁体中文；**以下是依据传递进来的文件名，使用后缀判断是何种文件类型*将对应的文件类型按照http定义的关键字发送回去
*/
const char *get_file_type(char *name)
{char* dot;dot = strrchr(name, '.');	//自右向左查找‘.’字符;如不存在返回NULLif (dot == (char*)0)return "text/plain; charset=utf-8";if (strcmp(dot, ".html") == 0 || strcmp(dot, ".htm") == 0)return "text/html; charset=utf-8";if (strcmp(dot, ".jpg") == 0 || strcmp(dot, ".jpeg") == 0)return "image/jpeg";if (strcmp(dot, ".gif") == 0)return "image/gif";if (strcmp(dot, ".png") == 0)return "image/png";if (strcmp(dot, ".css") == 0)return "text/css";if (strcmp(dot, ".au") == 0)return "audio/basic";if (strcmp( dot, ".wav") == 0)return "audio/wav";if (strcmp(dot, ".avi") == 0)return "video/x-msvideo";if (strcmp(dot, ".mov") == 0 || strcmp(dot, ".qt") == 0)return "video/quicktime";if (strcmp(dot, ".mpeg") == 0 || strcmp(dot, ".mpe") == 0)return "video/mpeg";if (strcmp(dot, ".vrml") == 0 || strcmp(dot, ".wrl") == 0)return "model/vrml";if (strcmp(dot, ".midi") == 0 || strcmp(dot, ".mid") == 0)return "audio/midi";if (strcmp(dot, ".mp3") == 0)return "audio/mpeg";if (strcmp(dot, ".ogg") == 0)return "application/ogg";if (strcmp(dot, ".pac") == 0)return "application/x-ns-proxy-autoconfig";return "text/plain; charset=utf-8";
}int send_file_to_http(const char *filename, struct bufferevent *bev)
{int fd = open(filename, O_RDONLY);int ret = 0;char buf[4096] = {0};while((ret = read(fd, buf, sizeof(buf)) ) ){bufferevent_write(bev, buf, ret);memset(buf, 0, ret);}close(fd);return 0;
}int send_header(struct bufferevent *bev, int no, const char* desp, const char *type, long len)
{char buf[256]={0};sprintf(buf, "HTTP/1.1 %d %s\r\n", no, desp);//HTTP/1.1 200 OK\r\nbufferevent_write(bev, buf, strlen(buf));// 文件类型sprintf(buf, "Content-Type:%s\r\n", type);bufferevent_write(bev, buf, strlen(buf));// 文件大小sprintf(buf, "Content-Length:%ld\r\n", len);bufferevent_write(bev, buf, strlen(buf));// Connection: closebufferevent_write(bev, _HTTP_CLOSE_, strlen(_HTTP_CLOSE_));//send \r\nbufferevent_write(bev, "\r\n", 2);return 0;
}int send_error(struct bufferevent *bev)
{send_header(bev,404, "File Not Found", "text/html", -1);send_file_to_http("404.html", bev);return 0;
}int send_dir(struct bufferevent *bev,const char *dirname)
{char encoded_name[1024];char path[1024];char timestr[64];struct stat sb;struct dirent **dirinfo;int i;char buf[4096] = {0};sprintf(buf, "<html><head><meta charset=\"utf-8\"><title>%s</title></head>", dirname);sprintf(buf+strlen(buf), "<body><h1>当前目录：%s</h1><table>", dirname);//添加目录内容int num = scandir(dirname, &dirinfo, NULL, alphasort);for(i=0; i<num; ++i){// 编码strencode(encoded_name, sizeof(encoded_name), dirinfo[i]->d_name);sprintf(path, "%s%s", dirname, dirinfo[i]->d_name);printf("############# path = %s\n", path);if (lstat(path, &sb) < 0){sprintf(buf+strlen(buf), "<tr><td><a href=\"%s\">%s</a></td></tr>\n", encoded_name, dirinfo[i]->d_name);}else{strftime(timestr, sizeof(timestr), "  %d  %b   %Y  %H:%M", localtime(&sb.st_mtime));if(S_ISDIR(sb.st_mode)){sprintf(buf+strlen(buf), "<tr><td><a href=\"%s/\">%s/</a></td><td>%s</td><td>%ld</td></tr>\n",encoded_name, dirinfo[i]->d_name, timestr, sb.st_size);}else{sprintf(buf+strlen(buf), "<tr><td><a href=\"%s\">%s</a></td><td>%s</td><td>%ld</td></tr>\n", encoded_name, dirinfo[i]->d_name, timestr, sb.st_size);}}bufferevent_write(bev, buf, strlen(buf));memset(buf, 0, sizeof(buf));}sprintf(buf+strlen(buf), "</table></body></html>");bufferevent_write(bev, buf, strlen(buf));printf("################# Dir Read OK !!!!!!!!!!!!!!\n");return 0;
}void conn_readcb(struct bufferevent *bev, void *user_data)
{printf("******************** begin call %s.........\n",__FUNCTION__);char buf[4096]={0};char method[50], path[4096], protocol[32];bufferevent_read(bev, buf, sizeof(buf));printf("buf[%s]\n", buf);sscanf(buf, "%[^ ] %[^ ] %[^ \r\n]", method, path, protocol);printf("method[%s], path[%s], protocol[%s]\n", method, path, protocol);if(strcasecmp(method, "GET") == 0){response_http(bev, method, path);}printf("******************** end call %s.........\n", __FUNCTION__);
}void conn_eventcb(struct bufferevent *bev, short events, void *user_data)
{printf("******************** begin call %s.........\n", __FUNCTION__);if (events & BEV_EVENT_EOF){printf("Connection closed.\n");}else if (events & BEV_EVENT_ERROR){printf("Got an error on the connection: %s\n",strerror(errno));}bufferevent_free(bev);printf("******************** end call %s.........\n", __FUNCTION__);
}void signal_cb(evutil_socket_t sig, short events, void *user_data)
{struct event_base *base = user_data;struct timeval delay = { 1, 0 };printf("Caught an interrupt signal; exiting cleanly in one seconds.\n");event_base_loopexit(base, &delay);
}void listener_cb(struct evconnlistener *listener, evutil_socket_t fd, struct sockaddr *sa, int socklen, void *user_data)
{printf("******************** begin call-------%s\n",__FUNCTION__);struct event_base *base = user_data;struct bufferevent *bev;printf("fd is %d\n",fd);bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);if (!bev){fprintf(stderr, "Error constructing bufferevent!");event_base_loopbreak(base);return;}bufferevent_flush(bev, EV_READ | EV_WRITE, BEV_NORMAL);bufferevent_setcb(bev, conn_readcb, NULL, conn_eventcb, NULL);bufferevent_enable(bev, EV_READ | EV_WRITE);printf("******************** end call-------%s\n",__FUNCTION__);
}/** 这里的内容是处理%20之类的东西！是"解码"过程。* %20 URL编码中的‘ ’(space)* %21 '!' %22 '"' %23 '#' %24 '$'* %25 '%' %26 '&' %27 ''' %28 '('......* 相关知识html中的‘ ’(space)是&nbsp*/
void strdecode(char *to, char *from)
{for ( ; *from != '\0'; ++to, ++from){if (from[0] == '%' && isxdigit(from[1]) && isxdigit(from[2])){// 依次判断from中 %20 三个字符*to = hexit(from[1])*16 + hexit(from[2]);// 移过已经处理的两个字符(%21指针指向1),表达式3的++from还会再向后移一个字符from += 2;}else{*to = *from;}}*to = '\0';
}//16进制数转化为10进制, return 0不会出现
int hexit(char c)
{if (c >= '0' && c <= '9')return c - '0';if (c >= 'a' && c <= 'f')return c - 'a' + 10;if (c >= 'A' && c <= 'F')return c - 'A' + 10;return 0;
}// "编码"，用作回写浏览器的时候，将除字母数字及/_.-~以外的字符转义后回写。
// strencode(encoded_name, sizeof(encoded_name), name);
void strencode(char* to, size_t tosize, const char* from)
{int tolen;for (tolen = 0; *from != '\0' && tolen + 4 < tosize; ++from){if (isalnum(*from) || strchr("/_.-~", *from) != (char*)0){*to = *from;++to;++tolen;}else{sprintf(to, "%%%02x", (int) *from & 0xff);to += 3;tolen += 3;}}*to = '\0';
}