相信大家对Apache都有所听闻，Apache是目前使用最为广泛我Web服务器。大家可以从news.netcraft.com/这个网站得到证实。
这是腾讯的uptime.netcraft.com/up/graph?site=www.qq.com.Apache强大的功能和高效的性能并且开放源代码的这种模式对我很有吸引力，但无赖自己水平有限，无法从Apache庞大的source code里面理清头绪。于是，我就冒出了个自己动手写一个小型的简单的Web服务器的想法，希望对这方面也和我一样感兴趣的朋友有所帮助。
我的实验环境为:
OS:Red Hat Enterprise Linux 5
gcc:4.1.2
libc:2.5
editor:Vim
lang:C
阅读该源代码需要以下预备知识：
C语言基础
Linux编程基础
socket编程基础(Linux)
TCP/IP基本原理
HTTP基本原理
关键字(Key Words):
Linux C, Web HTTP Server, Linux Socket.
-----------------------------------------------------------------------------------
下面是Mutu的第一个版本(0.1 Alpha)，实现了WEB 服务器的最基本功能
包括以下源文件:
webserver.c----程序入口
init_socket.h init_socket.c----完成一些WEB服务器的初始化工作
get_time.h get_time.c----获得服务器的时间
http_session.h http_session.c----处理一次HTTP会话
以下是各文件源码：
webserver.c:
/*
* file:webserver.c
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<strings.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include"get_time.h"
#include"init_socket.h"
#include"http_session.h"
intmain(intargc,char*argv[])
{
intlisten_fd;
intconnect_fd;
structsockaddr_inserver_addr;
structsockaddr_inclient_addr;
bzero(&server_addr,sizeof(structsockaddr_in));
bzero(&client_addr,sizeof(structsockaddr_in));
if(init_socket(&listen_fd,&server_addr)==-1)
{
perror("init_socket() error. in webserver.c");
exit(EXIT_FAILURE);
}
socklen_taddrlen=sizeof(structsockaddr_in);
pid_tpid;
while(1)
{
if((connect_fd=accept(listen_fd,(structsockaddr*)&client_addr,&addrlen))==-1)
{
perror("accept() error. in webserver.c");
continue;
}
if((pid=fork())>0)
{
close(connect_fd);
continue;
}
elseif(pid==0)
{
close(listen_fd);
printf("pid %d process http session from %s : %d\n",getpid(),inet_ntoa(client_addr.sin_addr),htons(client_addr.sin_port));
if(http_session(&connect_fd,&client_addr)==-1)
{
perror("http_session() error. in webserver.c");
shutdown(connect_fd,SHUT_RDWR);
printf("pid %d loss connection to %s\n",getpid(),inet_ntoa(client_addr.sin_addr));
exit(EXIT_FAILURE);/* exit from child process, stop this http session */
}
printf("pid %d close connection to %s\n",getpid(),inet_ntoa(client_addr.sin_addr));
shutdown(connect_fd,SHUT_RDWR);
exit(EXIT_SUCCESS);
}
else
{
perror("fork() error. in webserver.c");
exit(EXIT_FAILURE);
}
}
shutdown(listen_fd,SHUT_RDWR);
return0;
}
init_socket.h
/*
* file:init_socket.h
*/
#ifndefINIT_SOCKET_H
#defineINIT_SOCKET_H
#include<netinet/in.h>
#defineBACKLOG 20/* length of listening queue on socket */
#definePORT 8080/* web server listening port */
/* initialize the socket on server, include below
socket();
bind();
listen();
*/
/* listen_fd : the web server listen file decriptor
server_addr: the web server ipv4 address
RETURNS: success on 0, error on -1
*/
intinit_socket(int*listen_fd,structsockaddr_in*server_addr);
#endif
init_socket.c
/*
* file:init_socket.c
*/
#include<stdio.h>
#include<strings.h>
#include<unistd.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
#include"init_socket.h"
intinit_socket(int*listen_fd,structsockaddr_in*server_addr)
{
if((*listen_fd=socket(AF_INET,SOCK_STREAM,0))==-1)
{
perror("socket() error. in init_socket.c");
return-1;
}
/* set reuse the port on server machine */
intopt=SO_REUSEADDR;
if(setsockopt(*listen_fd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt))==-1)
{
perror("setsockopt() error. in init_socket.c");
return-1;
}
server_addr->sin_family=AF_INET;
server_addr->sin_port=htons(PORT);
server_addr->sin_addr.s_addr=htonl(INADDR_ANY);
if(bind(*listen_fd,(structsockaddr*)server_addr,sizeof(structsockaddr_in))==-1)
{
perror("bind() error. in init_socket.c");
return-1;
}
if(listen(*listen_fd,BACKLOG)==-1)
{
perror("listen() error. in init_socket.c");
return-1;
}
return0;
}
get_time.h
/*
* file: get_time.h
*/
#ifndefGET_TIME_H
#defineGET_TIME_H
#defineTIME_BUFFER_SIZE 40/* buffer size of time_buffer */
char*get_time_str(char*time_buf);
#endif
get_time.c
/*
* file:get_time.c
*/
#include<time.h>
#include<stdio.h>
#include<string.h>
#include"get_time.h"
/* get the time on server,
return: the ascii string of time , NULL on error
argument: time_buf the buffer to store time_string
*/
char*get_time_str(char*time_buf)
{
time_tnow_sec;
structtm*time_now;
if(time(&now_sec)==-1)
{
perror("time() in get_time.c");
returnNULL;
}
if((time_now=gmtime(&now_sec))==NULL)
{
perror("localtime in get_time.c");
returnNULL;
}
char*str_ptr=NULL;
if((str_ptr=asctime(time_now))==NULL)
{
perror("asctime in get_time.c");
returnNULL;
}
strcat(time_buf,str_ptr);
returntime_buf;
}
http_session.c
/*
* file: http_session.h
*/
#ifndefHTTP_SESSION_H
#defineHTTP_SESSION_H
#include<netinet/in.h>
#defineRECV_BUFFER_SIZE 1024/* 1KB of receive buffer */
#defineSEND_BUFFER_SIZE 1050000/* 1.xMB of send buffer */
#defineURI_SIZE 128/* length of uri request from client browse */
#defineTIME_OUT_SEC 10/* select timeout of secend */
#defineTIME_OUT_USEC 0/* select timeout of usecend */
#defineFILE_OK 200
#defineFILE_FORBIDEN 403/* there are no access permission*/
#defineFILE_NOT_FOUND 404/* file not found on server */
#defineUNALLOW_METHOD 405/* un allow http request method*/
#defineFILE_TOO_LARGE 413/* file is too large */
#defineURI_TOO_LONG 414/* */
#defineUNSUPPORT_MIME_TYPE 415
#defineUNSUPPORT_HTTP_VERSION 505
#defineFILE_MAX_SIZE 1048576/* 1MB the max siee of file read from hard disk */
#defineALLOW"Allow:GET"/* the server allow GET request method*/
#defineSERVER"Server:Mutu(0.1 Alpha)/Linux"
/* if the connect protocol is http then this function deal with it */
inthttp_session(int*connect_fd,structsockaddr_in*client_addr);
/* if http protocol return 1, else return 0 */
intis_http_protocol(char*msg_from_client);
/* get the request header's uri */
char*get_uri(char*req_header,char*uri_buf);
/* get the uri status,access return 0, not exist return 1, permission deny return 2, error return -1 */
intget_uri_status(char*uri);
/* get the mime type of the file request in uri from client's browse */
char*get_mime_type(char*uri);
/* read the file which requested by client in uri ,and store in entity_buf.
success return bytes readed,error return -1
*/
intget_file_disk(char*uri,unsignedchar*entity_buf);
/* set http replay header's status:
200:ok
404:file not found
*/
intset_rep_status();
intset_error_information(unsignedchar*send_buf,interrorno);
intreply_normal_information(unsignedchar*send_buf,unsignedchar*file_buf,intfile_size,char*mime_type);
#endif
如何访问该服务器呢？
首先你要知道运行服务器主机的IP，在服务器主机上输入如下命令(需要超级用户权限)：
ifconfig
如果你的是以太网(ethernet),那么会看到这样一行
inet addr:xxx.xxx.xxx broadcast:xxx.xxx.xxx.xxx mask:255.xxx.xxx.xxx
xxx代表数字（000-255），第一个inet addr后面的数字便是你的网卡地址。
如果你是在本机进行测试，那IP地址可以直接用127.0.0.1(回环地址，localhost)
取得服务器的IP后，用你喜欢的一款浏览器便可以访问WEB SERVER的内容了。
方法为：在浏览器的地址栏内输入:
http://xxx.xxx.xxx.xxx:8080
回车，即可（xxx.xxx.xxx.xxx无刚取得的服务器IP地址，8080为预设的端口）。