实现web服务器中的gzip

/* 
*主要实现功能，对传输的数据使用gzip进行压缩了
*1.实现绑定本机机器的1024端口作为ReageWeb服务提供网页服务的端口。（避免与机器上装有web服务器产生端口冲突）
* 作者：Reage
* blog:http://blog.csdn.net/rentiansheng
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <zlib.h>

#define OS_CODE 0x03 /*Unix OS_CODE*/
#define DEFAULT_COMPRESSION Z_DEFAULT_COMPRESSION
#define DEFAULT_WINDOWSIZE -15
#define DEFAULT_MEMLEVEL 9
#define DEFAULT_BUFFERSIZE 8096
#define MAX 1024
#define METHOD 20 //获取数据的方式,使用字符串的长度
#define URI 255 //表示URI的最大长度
#define VERSION 15	//HTTP版本好的最大长度
#define TYPE 20     //表示文件的类型的长度


int res_socket;
void app_exit();

static const char gzip_header[10] = {'\037', '\213', Z_DEFLATED, 0, 0, 0, 0, 0, 0, OS_CODE};

void put_long (unsigned char *string, unsigned long x) {
	string[0] = (x & 0xff);
	string[1] = ((x >> 8) & 0xff) ;
	string[2] = ((x >> 16) & 0xff) ;
	string[3] = ((x >> 24) & 0xff);
}



/*
@description:将数据使用gzip压缩后发给浏览器
@parameter
sockd:套接字
file: 要压缩的内容了
*/
int gzip_buffer (int  sockd, char * msg, int len) {
	z_stream stream;//zlib使用的。
	int ret, flush;
	char in[MAX];//存放输入的数据
	char send[MAX + 18 ];//存放压缩过后的数据
	unsigned have;
	memcpy (send, gzip_header, 10);
	memset (in, 0, len);
	stream.zalloc = Z_NULL;
	stream.zfree = Z_NULL;
	stream.opaque = Z_NULL;
	stream.avail_in = 0;
	stream.next_in = Z_NULL;
	memcpy (in, msg, len);
	//压缩初始化。
	int tmp_result = deflateInit2(&stream,
								Z_DEFAULT_COMPRESSION,//压缩级别
								Z_DEFLATED,//压缩方式
								-MAX_WBITS,
								8,
								Z_DEFAULT_STRATEGY);
	if (Z_OK != tmp_result) {
		printf("deflateInit error: %d\r\n", tmp_result);
		return 0;
	}
	stream.avail_in = len; //要压缩数据的长度
	stream.next_in = in;	//要压缩数据的首地址
	stream.avail_out = MAX;  //可存放的最大输出结果的长多。就是压缩后数据的最大长度
	stream.next_out = send + 10; //存放压缩数据的开始位置，send前十个字节用来放头部
	ret = deflate (&stream,Z_FINISH); //压缩
	assert (ret != Z_STREAM_ERROR);
	switch (ret) { 
		case Z_NEED_DICT:
			ret = Z_DATA_ERROR;
		case Z_DATA_ERROR:
		case Z_MEM_ERROR:
			(void)inflateEnd (&stream);
			return ret;
	}
	have = MAX - stream.avail_out;
	unsigned crc = crc32(0L, in, len); 
	char * tail = send + 10 + have;
	put_long (tail, crc);
	put_long (tail + 4, len);
	write (sockd, send, have + 18);
	deflateEnd (&stream);
	return 1;
}

/* 
@description:开始服务端监听
@parameter
ip:web服务器的地址
port：web服务器的端口
@result：成功返回创建socket套接字标识，错误返回-1

*/
int socket_listen( char *ip, unsigned short int port){
	int res_socket; //返回值
	int res, on;
	struct sockaddr_in address;
	struct in_addr in_ip;
	res = res_socket = socket(AF_INET, SOCK_STREAM, 0);
	setsockopt(res_socket, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
	memset(&address, 0, sizeof(address));
	address.sin_family = AF_INET ;
	address.sin_port =htons(port);
	address.sin_addr.s_addr = htonl(INADDR_ANY); //inet_addr("127.0.0.1");
	res = bind( res_socket, (struct sockaddr *) &address, sizeof( address ) );
	if(res) { printf( "port is used , not to repeat bind\n" ); exit(101); };
	res = listen(res_socket,5);
	if(res) { printf( "listen port is error ;\n" ); exit( 102 );  };
	return res_socket ;
}

/*
@description:向客户端发送网页头文件的信息
@parameter
conn_socket:套接字描述符。
status:http协议的返回状态码。
@s_status:http协议的状态码的含义
@filetype:向客户端发送的文件类型
*/
void send_http_head(int conn_socket){ 
	char buf[MAX];
	memset(buf, 0, MAX);
	sprintf(buf, "HTTP/1.0 %d OK\r\n", 200);
	sprintf(buf, "%sServer: Reage Web Server\r\n", buf);
	sprintf(buf, "%sContent-Type: text/html\r\n", buf);
	sprintf(buf, "%sContent-Encoding: gzip\r\n\r\n", buf);
	write(conn_socket, buf, strlen(buf));
} 



int main(int argc, char * argv[] ){  
	int  conn_socket;
	int tmp ;
	int line ;
	struct sockaddr_in client_addr;
	char buf[MAX];
	int len = sizeof(client_addr);
	char method[METHOD], uri[MAX], version[VERSION], type[TYPE];
	char msg[] = "<br><br><h1>Reage Web Server gzip support text!</h1><br/><h1><a href = \"http://blog.csdn.net/rentiansheng\">Reage blog</a>";
	res_socket = socket_listen( "127.0.0.1", 1024) ;
	//当按ctrl+c结束程序时调用，使用app_exit函数处理退出过程
	signal(SIGINT, app_exit);
	while(1){
		conn_socket = accept( res_socket, (struct sockaddr * )&client_addr, &len );
		printf("reage\n");
		tmp = read (conn_socket, buf, MAX-1);
		buf [MAX - 1] = 0;
		send_http_head(conn_socket);
		gzip_buffer (conn_socket, msg, strlen(msg));
		close(conn_socket);
  	} 

}

void app_exit(){
	//回复ctrl+c组合键的默认行为
	signal (SIGINT, SIG_DFL);
	//关闭服务端链接、释放服务端ip和端口
	close(res_socket);
	printf("\n");
	exit(0);
}