linux编程c语言epoll小型http服务器

蔚落 2022-12-03 02:22 104阅读 0赞

# linux编程c语言epoll小型http服务器 #

# 模型 #

## 服务器端实现 ##

void http_respond_head(int cfd, char* type)
    { 
        char buf[1024];
        // 状态行
        sprintf(buf, "http/1.1 200 OK\r\n");
        write(cfd, buf, strlen(buf));
        // 消息报头
        sprintf(buf, "Content-Type: %s\r\n", type);
        write(cfd, buf, strlen(buf));
        // 空行
        write(cfd, "\r\n", 2);
    }

main

void main()
    { 
        // 修改进程的工作目录
        chdir(path);
        // 创建监听的套接字
        int lfd = socket(af_inet, sock_stream, 0);
        // 绑定
        struct sockaddr_in serv;
        serv.family = af_inet;
        serv.port = htons(8989);
        bind(lfd, &serv, len);
        // 监听
        listen();
        
        int cfd = accept();
        // 读数据
        read(cfd, buf, sizeof(buf));
        // 先将buf中的请求行拿出来
        // GET /hello.c http/1.1
        char method[12], path[1024], protocol[12];
        // 得到文件名
        char* file = path+1;
        // 打开文件
        int fdd = open(file, O_RDONLY);
        int len = 0;
        http_respond_head(cfd, "text/plain");
        // 循环读数据
        while( (len=read(fdd, buf, sizeof(buf))) > 0)
        { 
        	// 数据发送给浏览器
    		write(fdd, buf, len));
        }    
    }

# main.c #

#include <stdio.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include "epoll_server.h"
    
    int main(int argc, const char* argv[])
    { 
        if(argc < 3)
        { 
            printf("eg: ./a.out port path\n");
            exit(1);
        }
    
        // 端口
        int port = atoi(argv[1]);
        // 修改进程的工作目录, 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\_server.h #

#ifndef _EPOLL_SERVER_H
    #define _EPOLL_SERVER_H
    
    int init_listen_fd(int port, int epfd);
    void epoll_run(int port);
    void do_accept(int lfd, int epfd);
    void do_read(int cfd, int epfd);
    int get_line(int sock, char *buf, int size);
    void disconnect(int cfd, int epfd);
    void http_request(const char* request, int cfd);
    void send_respond_head(int cfd, int no, const char* desp, const char* type, long len);
    void send_file(int cfd, const char* filename);
    void send_dir(int cfd, const char* dirname);
    void encode_str(char* to, int tosize, const char* from);
    void decode_str(char *to, char *from);
    const char *get_file_type(const char *name);
    
    #endif

# epoll\_server.c #

#include <stdio.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 2000
    
    void epoll_run(int port)
    { 
        // 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lfd
        int 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, -1);
            if(ret == -1)
            { 
                perror("epoll_wait error");
                exit(1);
            }
    
            // 遍历发生变化的节点
            for(int 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
                    do_read(pev->data.fd, epfd);
                }
            }
        }
    }
    
    // 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del
            disconnect(cfd, epfd);         
        }
        else
        { 
            printf("请求行数据: %s", line);
            printf("============= 请求头 ============\n");
            // 还有数据没读完
            // 继续读
            while(len)
            { 
                char buf[1024] = { 0};
                len = get_line(cfd, buf, sizeof(buf));
                printf("-----: %s", buf);
            }
            printf("============= The End ============\n");
        }
    
        // 请求行: get /xxx http/1.1
        // 判断是不是get请求
        if(strncasecmp("get", line, 3) == 0)
        { 
            // 处理http请求
            http_request(line, cfd);
            // 关闭套接字, cfd从epoll上del
            disconnect(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
        // get /xxx http/1.1
        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 %5f
        decode_str(path, path);
            // 处理path /xx
            // 去掉path中的/
            char* file = path+1;
        // 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)
        { 
            // show 404
            send_respond_head(cfd, 404, "File Not Found", ".html", -1);
            send_file(cfd, "404.html");
        }
    
        // 判断是目录还是文件
        // 如果是目录
        if(S_ISDIR(st.st_mode))
        { 
            // 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)
    { 
        // 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(int 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);
    
            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);
            }
            // 如果是目录
            else if(S_ISDIR(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);
            }
            send(cfd, buf, strlen(buf), 0);
            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)
        { 
            // show 404
            return;
        }
    
        // 循环读文件
        char buf[4096] = { 0};
        int len = 0;
        while( (len = read(fd, buf, sizeof(buf))) > 0 )
        { 
            // 发送读出的数据
            send(cfd, buf, len, 0);
        }
        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port
        struct 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NULL
        dot = 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";
    }

# 其它 #

// 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NULL
        dot = 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";
    }
    
    // 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';
    }
    
    // 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);
    }