http小记

http粘包

现象

如:客户端连续3次send 1k数据,并且每次发送间隔没有很明确(可以理解为每次发送间隔很短很短),会让服务器误以为客户端一次发送了3k的数据。因此服务器只会recv一次并且send一次返回给客户端,导致客户端只recv一次,与其send的次数不匹配。

解决办法

1、解析http数据,用\r\n\r\n进行区分(head中每一行都有/r/n,而head与body之间有一个空行,因此会有两个/r/n)
2、在http的head中定义包的长度(content-length)

sendfile函数

在两个文件描述符之间传递数据(完全在内核中操作),从而避免了内核缓冲区和用户缓冲区之间的数据拷贝,效率很高,被称为零拷贝。函数定义为:

#include<sys/sendfile.h>
ssize_t senfile(int out_fd,int in_fd,off_t* offset,size_t count);

http基于recator实现




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

#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

#include <sys/stat.h>
#include <sys/sendfile.h>



#define BUFFER_LENGTH		4096
#define MAX_EPOLL_EVENTS	1024
#define SERVER_PORT			8888
#define PORT_COUNT			1



#define HTTP_WEBSERVER_HTML_ROOT	"html"


#define HTTP_METHOD_GET		0
#define HTTP_METHOD_POST	1

typedef int NCALLBACK(int ,int, void*);

struct ntyevent {
	int fd;
	int events;
	void *arg;
	int (*callback)(int fd, int events, void *arg);
	
	int status;
	char buffer[BUFFER_LENGTH];
	int length;
	long last_active;

	// http param
	int method; //
	char resource[BUFFER_LENGTH];
	int ret_code;
	
	
};

struct eventblock {

	struct eventblock *next;
	struct ntyevent *events;
	
};

struct ntyreactor {
	int epfd;
	int blkcnt;
	struct eventblock *evblk; //fd --> 100w
};


int recv_cb(int fd, int events, void *arg);
int send_cb(int fd, int events, void *arg);
struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd);


void nty_event_set(struct ntyevent *ev, int fd, NCALLBACK callback, void *arg) {

	ev->fd = fd;
	ev->callback = callback;
	ev->events = 0;
	ev->arg = arg;
	ev->last_active = time(NULL);

	return ;
	
}


int nty_event_add(int epfd, int events, struct ntyevent *ev) {

	struct epoll_event ep_ev = {0, {0}};
	ep_ev.data.ptr = ev;
	ep_ev.events = ev->events = events;

	int op;
	if (ev->status == 1) {
		op = EPOLL_CTL_MOD;
	} else {
		op = EPOLL_CTL_ADD;
		ev->status = 1;
	}

	if (epoll_ctl(epfd, op, ev->fd, &ep_ev) < 0) {
		printf("event add failed [fd=%d], events[%d]\n", ev->fd, events);
		return -1;
	}

	return 0;
}

int nty_event_del(int epfd, struct ntyevent *ev) {

	struct epoll_event ep_ev = {0, {0}};

	if (ev->status != 1) {
		return -1;
	}

	ep_ev.data.ptr = ev;
	ev->status = 0;
	epoll_ctl(epfd, EPOLL_CTL_DEL, ev->fd, &ep_ev);

	return 0;
}


int readline(char *allbuf, int idx, char *linebuf) {

	int len = strlen(allbuf);

	for(;idx < len;idx ++) {
		if (allbuf[idx] == '\r' && allbuf[idx+1] == '\n') {
			return idx+2;
		} else {
			*(linebuf++) = allbuf[idx];
		}
	}

	return -1;
}

int http_request(struct ntyevent *ev) {

	// GET, POST
	char linebuf[1024] = {0};
	int idx = readline(ev->buffer, 0, linebuf);

	if (strstr(linebuf, "GET")) {
		ev->method = HTTP_METHOD_GET;

		//uri
		int i = 0;
		while (linebuf[sizeof("GET ") + i] != ' ') i++;
		linebuf[sizeof("GET ")+i] = '\0';

		sprintf(ev->resource, "./%s/%s", HTTP_WEBSERVER_HTML_ROOT, linebuf+sizeof("GET "));
		
	} else if (strstr(linebuf, "POST")) {

	}

}

int recv_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	struct ntyevent *ev = ntyreactor_idx(reactor, fd);

	int len = recv(fd, ev->buffer, BUFFER_LENGTH, 0); // 
	
	if (len > 0) {
		
		ev->length = len;
		ev->buffer[len] = '\0';

		printf("C[%d]:%s\n", fd, ev->buffer); //http

		http_request(ev);

		//send();
		
		nty_event_del(reactor->epfd, ev);
		nty_event_set(ev, fd, send_cb, reactor);
		nty_event_add(reactor->epfd, EPOLLOUT, ev);
		
		
	} else if (len == 0) {

		nty_event_del(reactor->epfd, ev);
		close(ev->fd);
		//printf("[fd=%d] pos[%ld], closed\n", fd, ev-reactor->events);
		 
	} else {

		nty_event_del(reactor->epfd, ev);
		close(ev->fd);
		printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));
		
	}

	return len;
}


int http_response(struct ntyevent *ev) {

	if (ev == NULL) return -1;
	memset(ev->buffer, 0, BUFFER_LENGTH);
#if 0
	const char *html = "<html><head><title>hello http</title></head><body><H1>King</H1></body></html>\r\n\r\n";
						  	   
	ev->length = sprintf(ev->buffer, 
		"HTTP/1.1 200 OK\r\n\
		 Date: Thu, 11 Nov 2021 12:28:52 GMT\r\n\
		 Content-Type: text/html;charset=ISO-8859-1\r\n\
		 Content-Length: 83\r\n\r\n%s", 
		 html);
	
#else

	printf("resource: %s\n", ev->resource);

	int filefd = open(ev->resource, O_RDONLY);
	if (filefd == -1) { // return 404

		ev->ret_code = 404;
		ev->length = sprintf(ev->buffer, 
			"HTTP/1.1 404 Not Found\r\n"
		 	"Date: Thu, 11 Nov 2021 12:28:52 GMT\r\n"
		 	"Content-Type: text/html;charset=ISO-8859-1\r\n"
			"Content-Length: 85\r\n\r\n"
		 	"<html><head><title>404 Not Found</title></head><body><H1>404</H1></body></html>\r\n\r\n" );

	} else {


		struct stat stat_buf;
		fstat(filefd, &stat_buf);
		close(filefd);

		if (S_ISDIR(stat_buf.st_mode)) {

			
			ev->ret_code = 404;
			ev->length = sprintf(ev->buffer, 
				"HTTP/1.1 404 Not Found\r\n"
				"Date: Thu, 11 Nov 2021 12:28:52 GMT\r\n"
				"Content-Type: text/html;charset=ISO-8859-1\r\n"
				"Content-Length: 85\r\n\r\n"
				"<html><head><title>404 Not Found</title></head><body><H1>404</H1></body></html>\r\n\r\n" );

		} else if (S_ISREG(stat_buf.st_mode)) {

			ev->ret_code = 200;

			ev->length = sprintf(ev->buffer, 
				"HTTP/1.1 200 OK\r\n"
			 	"Date: Thu, 11 Nov 2021 12:28:52 GMT\r\n"
			 	"Content-Type: text/html;charset=ISO-8859-1\r\n"
				"Content-Length: %ld\r\n\r\n", 
			 		stat_buf.st_size );
		}

	}

#endif
	return ev->length;
}

int send_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	struct ntyevent *ev = ntyreactor_idx(reactor, fd);

	http_response(ev);
	//
	int len = send(fd, ev->buffer, ev->length, 0);
	if (len > 0) {
		printf("send[fd=%d], [%d]%s\n", fd, len, ev->buffer);

		if (ev->ret_code == 200) {
			int filefd = open(ev->resource, O_RDONLY);
			struct stat stat_buf;
			fstat(filefd, &stat_buf);

			sendfile(fd, filefd, NULL, stat_buf.st_size);
			close(filefd);
		}
		

		nty_event_del(reactor->epfd, ev);
		nty_event_set(ev, fd, recv_cb, reactor);
		nty_event_add(reactor->epfd, EPOLLIN, ev);
		
	} else {

		close(ev->fd);

		nty_event_del(reactor->epfd, ev);
		printf("send[fd=%d] error %s\n", fd, strerror(errno));

	}

	return len;
}

int accept_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	if (reactor == NULL) return -1;

	struct sockaddr_in client_addr;
	socklen_t len = sizeof(client_addr);

	int clientfd;

	if ((clientfd = accept(fd, (struct sockaddr*)&client_addr, &len)) == -1) {
		if (errno != EAGAIN && errno != EINTR) {
			
		}
		printf("accept: %s\n", strerror(errno));
		return -1;
	}

	

	int flag = 0;
	if ((flag = fcntl(clientfd, F_SETFL, O_NONBLOCK)) < 0) {
		printf("%s: fcntl nonblocking failed, %d\n", __func__, MAX_EPOLL_EVENTS);
		return -1;
	}

	struct ntyevent *event = ntyreactor_idx(reactor, clientfd);
	
	nty_event_set(event, clientfd, recv_cb, reactor);
	nty_event_add(reactor->epfd, EPOLLIN, event);

	
	printf("new connect [%s:%d], pos[%d]\n", 
		inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), clientfd);

	return 0;

}

int init_sock(short port) {

	int fd = socket(AF_INET, SOCK_STREAM, 0);
	fcntl(fd, F_SETFL, O_NONBLOCK);

	struct sockaddr_in server_addr;
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	server_addr.sin_port = htons(port);

	bind(fd, (struct sockaddr*)&server_addr, sizeof(server_addr));

	if (listen(fd, 20) < 0) {
		printf("listen failed : %s\n", strerror(errno));
	}

	return fd;
}


int ntyreactor_alloc(struct ntyreactor *reactor) {

	if (reactor == NULL) return -1;
	if (reactor->evblk == NULL) return -1;

	struct eventblock *blk = reactor->evblk;
	while (blk->next != NULL) {
		blk = blk->next;
	}

	struct ntyevent *evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
	if (evs == NULL) {
		printf("ntyreactor_alloc ntyevents failed\n");
		return -2;
	}
	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));

	struct eventblock *block = (struct eventblock *)malloc(sizeof(struct eventblock));
	if (block == NULL) {
		printf("ntyreactor_alloc eventblock failed\n");
		return -2;
	}
	memset(block, 0, sizeof(struct eventblock));

	block->events = evs;
	block->next = NULL;

	blk->next = block;
	reactor->blkcnt ++; //

	return 0;
}

struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd) {

	int blkidx = sockfd / MAX_EPOLL_EVENTS;

	while (blkidx >= reactor->blkcnt) {
		ntyreactor_alloc(reactor);
	}

	int i = 0;
	struct eventblock *blk = reactor->evblk;
	while(i ++ < blkidx && blk != NULL) {
		blk = blk->next;
	}

	return &blk->events[sockfd % MAX_EPOLL_EVENTS];
}


int ntyreactor_init(struct ntyreactor *reactor) {

	if (reactor == NULL) return -1;
	memset(reactor, 0, sizeof(struct ntyreactor));

	reactor->epfd = epoll_create(1);
	if (reactor->epfd <= 0) {
		printf("create epfd in %s err %s\n", __func__, strerror(errno));
		return -2;
	}

	struct ntyevent *evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
	if (evs == NULL) {
		printf("ntyreactor_alloc ntyevents failed\n");
		return -2;
	}
	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));

	struct eventblock *block = (struct eventblock *)malloc(sizeof(struct eventblock));
	if (block == NULL) {
		printf("ntyreactor_alloc eventblock failed\n");
		return -2;
	}
	memset(block, 0, sizeof(struct eventblock));

	block->events = evs;
	block->next = NULL;

	reactor->evblk = block;
	reactor->blkcnt = 1;

	return 0;
}

int ntyreactor_destory(struct ntyreactor *reactor) {

	close(reactor->epfd);
	//free(reactor->events);

	struct eventblock *blk = reactor->evblk;
	struct eventblock *blk_next = NULL;

	while (blk != NULL) {

		blk_next = blk->next;

		free(blk->events);
		free(blk);

		blk = blk_next;

	}
	
	return 0;
}



int ntyreactor_addlistener(struct ntyreactor *reactor, int sockfd, NCALLBACK *acceptor) {

	if (reactor == NULL) return -1;
	if (reactor->evblk == NULL) return -1;

	//reactor->evblk->events[sockfd];
	struct ntyevent *event = ntyreactor_idx(reactor, sockfd);

	nty_event_set(event, sockfd, acceptor, reactor);
	nty_event_add(reactor->epfd, EPOLLIN, event);

	return 0;
}



int ntyreactor_run(struct ntyreactor *reactor) {
	if (reactor == NULL) return -1;
	if (reactor->epfd < 0) return -1;
	if (reactor->evblk == NULL) return -1;
	
	struct epoll_event events[MAX_EPOLL_EVENTS+1];
	
	int checkpos = 0, i;

	while (1) {
/*
		long now = time(NULL);
		for (i = 0;i < 100;i ++, checkpos ++) {
			if (checkpos == MAX_EPOLL_EVENTS) {
				checkpos = 0;
			}

			if (reactor->events[checkpos].status != 1) {
				continue;
			}

			long duration = now - reactor->events[checkpos].last_active;

			if (duration >= 60) {
				close(reactor->events[checkpos].fd);
				printf("[fd=%d] timeout\n", reactor->events[checkpos].fd);
				nty_event_del(reactor->epfd, &reactor->events[checkpos]);
			}
		}
*/

		int nready = epoll_wait(reactor->epfd, events, MAX_EPOLL_EVENTS, 1000);
		if (nready < 0) {
			printf("epoll_wait error, exit\n");
			continue;
		}

		for (i = 0;i < nready;i ++) {

			struct ntyevent *ev = (struct ntyevent*)events[i].data.ptr;

			if ((events[i].events & EPOLLIN) && (ev->events & EPOLLIN)) {
				ev->callback(ev->fd, events[i].events, ev->arg);
			}
			if ((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)) {
				ev->callback(ev->fd, events[i].events, ev->arg);
			}
			
		}

	}
}

// 3, 6w, 1, 100 == 
// <remoteip, remoteport, localip, localport>
int main(int argc, char *argv[]) {

	unsigned short port = SERVER_PORT; // listen 8888
	if (argc == 2) {
		port = atoi(argv[1]);
	}
	struct ntyreactor *reactor = (struct ntyreactor*)malloc(sizeof(struct ntyreactor));
	ntyreactor_init(reactor);

	int i = 0;
	int sockfds[PORT_COUNT] = {0};
	for (i = 0;i < PORT_COUNT;i ++) {
		sockfds[i] = init_sock(port+i);
		ntyreactor_addlistener(reactor, sockfds[i], accept_cb);
	}

	
	ntyreactor_run(reactor);

	ntyreactor_destory(reactor);

	for (i = 0;i < PORT_COUNT;i ++) {
		close(sockfds[i]);
	}

	free(reactor);

	return 0;
}




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