第399页 第24章 实现简单的Web服务器端

Web服务器是以HTTP协议为基础传输超文本的服务器。
HTTP--Stateless协议
Web协议采用HTTP协议，即使使用IOCP或epoll模型也不会大幅提升性能。Stateless--交换一次数据之后即断开连接，没有足够时间发挥IOCP or epoll优势。在服务器端与客户端保持较长连接前提下频繁发送大小不一的消息时，才能真正发挥这2中模型的优势。最典型的场景就是网游服务器。
Hypertext--可跳转的文本，可以根据客户端请求而跳转的结构化信息。
/*************************************************************************
	> File Name: http_server.c
	> Author: xjhznick
	> Mail: xjhznick@gmail.com 
	> Created Time: 2015年04月03日 星期五 21时17分48秒
  > Description: a simple 基于Linux的多线程Web服务器
 ************************************************************************/

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<pthread.h>

#define BUFF_SIZE 1024
#define BUFF_SMALL 100

void *request_handler(void *arg);
void send_data(FILE *fp, char *ct, char *file_name);
void *content_type(char *file);
void send_error(FILE *fp);
void error_handler(char *message);

int main(int argc, char *argv[])
{
	int sock_server, sock_client;
	struct sockaddr_in addr_server, addr_client;
	int size_addr_client;
	char buff[BUFF_SIZE];
	pthread_t pthread_id;

	if(argc != 2){
		printf("Usage: %s <port>\n", argv[0]);
		exit(1);
	}

	sock_server = socket(PF_INET, SOCK_STREAM, 0);
	if(-1 == sock_server){
		error_handler("Error socket()");
	}

	memset(&addr_server, 0, sizeof(addr_server));
	addr_server.sin_family = AF_INET;
	addr_server.sin_addr.s_addr = htonl(INADDR_ANY);
	addr_server.sin_port = htons(atoi(argv[1]));

	if(-1 == bind(sock_server, (struct sockaddr*)&addr_server, sizeof(addr_server))){
		error_handler("Error bind()");
	}

	if(-1 == listen(sock_server, 5)){
		error_handler("Error listen()");
	}

	while(1){
		size_addr_client = sizeof(addr_client);
		sock_client = accept(sock_server, (struct sockaddr*)&addr_client, &size_addr_client);
		printf("Connection Request: %s:%d\n", inet_ntoa(addr_client.sin_addr), ntohs(addr_client.sin_port));
		pthread_create(&pthread_id, NULL, request_handler, &sock_client);
		pthread_detach(pthread_id);
	}

	close(sock_server);
	return 0;
}
void error_handler(char *msg)
{
	fputs(msg, stderr);
	fputs("\n", stderr);
	exit(1);
}

void *request_handler(void *arg)
{
	int sock_client = *((int *)arg);
	char req_line[BUFF_SMALL];
	FILE *read_fp;
	FILE *write_fp;

	char method[10];
	char ct[15];
	char file_name[30];

	read_fp = fdopen(sock_client, "r");
	write_fp = fdopen(dup(sock_client), "w");

	fgets(req_line, BUFF_SMALL, read_fp);
	if(strstr(req_line, "HTTP/")==NULL){
		fputs("Error 1\n", stderr);
		send_error(write_fp);
		fclose(read_fp);
		fclose(write_fp);
		return;
	}
	strcpy(method, strtok(req_line, " /"));
	strcpy(file_name, strtok(NULL, " /"));
	strcpy(ct, content_type(file_name));
	if(strcmp(method, "GET") != 0){
		fputs("Error 2\n", stderr);
		send_error(write_fp);
		fclose(read_fp);
		fclose(write_fp);
		return;
	}
	fclose(read_fp);
	send_data(write_fp, ct, file_name);
}

void send_data(FILE *fp, char *ct, char *file_name)
{
	char protocol[] = "HTTP/1.0 200 OK\r\n";
	char server[] = "Server: Linux web Server \r\n";
	char cnt_len[] = "Content-length:2048\r\n";
	char cnt_type[BUFF_SMALL];
	char buff[BUFF_SIZE];
	FILE *send_fp;

	sprintf(cnt_type, "Content-type:%s\r\n\r\n", ct);
	send_fp = fopen(file_name, "r");
	if(send_fp == NULL){
		fputs("Error 3\n", stderr);
		send_error(fp);
		return;
	}
	//Send Head Info
	fputs(protocol, fp);
	fputs(server, fp);
	fputs(cnt_len, fp);
	fputs(cnt_type, fp);
	//Send requested data
	while(fgets(buff, BUFF_SIZE, send_fp) != NULL){
		fputs(buff, fp);
		fflush(fp);
	}
	fflush(fp);
	fclose(fp);
}
void *content_type(char *file)
{
	char extension[BUFF_SMALL];
	char file_name[BUFF_SMALL];
	strcpy(file_name, file);
	strtok(file_name, ".");
	strcpy(extension, strtok(NULL, "."));

	if(!strcmp(extension, "html") || !strcmp(extension, "htm")){
		return "text/html";
	}else{
		return "text/plain";
	}
}
void send_error(FILE *fp)
{
	char protocol[] = "HTTP/1.0 4xx Bad Request\r\n";
	char server[] = "Server: Linux Web Server \r\n";
	char cnt_len[] = "Content-length:2048\r\n";
	char cnt_type[] = "Content-type:text/html\r\n\r\n";
	char content[] = "<html><head><title>NetWrok</title></head>"
		"<body><font size=+5><br>Error! Look up the request method and filename "
		"</font></body></html>";
	fputs(protocol, fp);
	fputs(server, fp);
	fputs(cnt_len, fp);
	fputs(cnt_type, fp);
	fputs(content, fp);
	fflush(fp);
}
$ ./a.out 9190
Connection Request: 127.0.0.1:46172
^C