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c_socket.io_server筆記之htmlfile塊傳輸

關于htmlfile chunked傳輸

Google天才工程師們使用一個稱為“htmlfile”的 ActiveX 解決了在 IE 中的加載顯示問題，具體是封裝了一個基于 iframe 和 htmlfile 的 JavaScript comet 對象，支持 IE、Mozilla Firefox 瀏覽器，但需要服務器端配合使用。
稍微熟悉一下有關Transfer-Encoding: chunked的同學，會感覺一點技術含量都沒有。但那是他們的事情，笨鳥先飛，記錄下來，以作備忘。
我們做一個時間顯示，每隔一秒自動顯示在頁面上。那么做這件事情的順序，就很簡單。

輸出頭部

chunked塊傳輸，需要瀏覽器支持，服務器需要提前告訴瀏覽器端：

#define HTMLFILE_RESPONSE_HEADER \
"HTTP/1.1 200 OK\r\n" \
"Connection: keep-alive\r\n" \
"Content-Type: text/html; charset=utf-8\r\n" \
"Transfer-Encoding: chunked\r\n" \
"\r\n"......
write_ori(client, HTMLFILE_RESPONSE_HEADER);

在socket.io服務器中，數據量不大，傳輸內容無須gzip壓縮，畢竟壓縮算法要耗費一些CPU時間。

傳輸部分HTML預備內容

這部分不是必須的，為了調用客戶端javascript方便，可以提前定義好調用函數。

#define HTMLFILE_RESPONSE_FIRST \
    "<html><head><title>htmlfile chunked example</title><script>var _ = function (msg) { document.getElementById('div').innerHTML = msg; };</script></head><body><div id=\"div\"></div>"......
char target_message[strlen(HTMLFILE_RESPONSE_FIRST) + 20];
sprintf(target_message, "%X\r\n%s\r\n", (int)strlen(HTMLFILE_RESPONSE_FIRST), HTMLFILE_RESPONSE_FIRST);
write_ori(client, target_message);

除了http header頭部輸出，剩下內容的輸出，需要注意輸出的簡單格式：

具體輸出內容長度16進制數字表示\r\n具體輸出內容\r\n

如

2D
<script>_('now time is 1364040943');</script>

掌握了格式要求之后，其它的，就沒有什么難點。

設置定時器，周期性循環

client->timeout.data = client;
ev_timer_init(&client->timeout, timeout_cb, 1.0, 1.0);
ev_timer_start(loop, &client->timeout);

時間觸發函數timeout_cb每一秒會定時觸發：

static void timeout_cb(EV_P_ struct ev_timer *timer, int revents) {
if (EV_ERROR & revents) {
    fprintf(stderr, "error event in timer_beat\n");
    return ;
}
if (timer == NULL) {
    fprintf(stderr, "the timer is NULL now !\n");
}
client_t *client = timer->data;
if (client == NULL) {
     fprintf(stderr, "Timeout the client is NULL !\n");
    return;
}
char target_msg[50];
snprintf(target_msg, 50, "now time is %d", (int)ev_time());
write_body(client, target_msg);
}

OK，基本功能完畢。

編譯運行

編譯一下：

gcc htmlfile.c -o htmlfile ../include/libev.a -lm

運行它：

./htmlfile

打開瀏覽器，輸入地址 http://192.168.190.150:8080/htmlfile，可以看到時間一點點的流逝，諸如：

now time is 1364043695

完整代碼

	#include <arpa/inet.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <err.h>

	#include "../include/ev.h"

	#define HTMLFILE_RESPONSE_HEADER \
	"HTTP/1.1 200 OK\r\n" \
	"Connection: keep-alive\r\n" \
	"Content-Type: text/html; charset=utf-8\r\n" \
	"Transfer-Encoding: chunked\r\n" \
	"\r\n"
	#define HTMLFILE_RESPONSE_FIRST \
	"<html><head><title>htmlfile chunked example</title><script>var _ = function (msg) { document.getElementById('div').innerHTML = msg; };</script></head><body><div id=\"div\"></div> "
	#define SERVER_PORT 8080
	struct ev_loop *loop;
	typedef struct {
	int fd;
	ev_io ev_read;
	ev_timer timeout;
	} client_t;

	ev_io ev_accept;

	static void free_res(struct ev_loop loop, ev_io ws);

	int setnonblock(int fd) {
	int flags = fcntl(fd, F_GETFL);
	if (flags < 0)
	return flags;

	flags \|= O_NONBLOCK;
	if (fcntl(fd, F_SETFL, flags) < 0)
	return -1;

	return 0;
	}

	static int format_message(const char ori_message, char target_message) {
	return sprintf(target_message, "%X\r\n<script>_('%s');</script>\r\n", ((int)strlen(ori_message) + 23), ori_message);
	}

	static void write_ori(client_t client, char msg) {
	if (client == NULL) {
	fprintf(stderr, "the client is NULL !\n");
	return;
	}

	write(client->fd, msg, strlen(msg));
	}

	static void write_body(client_t client, char msg) {
	char body_msg[strlen(msg) + 100];
	format_message(msg, body_msg);

	write_ori(client, body_msg);
	}

	static void timeout_cb(EV_P_ struct ev_timer *timer, int revents) {
	if (EV_ERROR & revents) {
	fprintf(stderr, "error event in timer_beat\n");
	return ;
	}

	if (timer == NULL) {
	fprintf(stderr, "the timer is NULL now !\n");
	}

	client_t *client = timer->data;
	if (client == NULL) {
	fprintf(stderr, "Timeout the client is NULL !\n");
	return;
	}

	char target_msg[50];
	snprintf(target_msg, 50, "now time is %d", (int)ev_time());
	write_body(client, target_msg);
	}

	static void read_cb(struct ev_loop loop, ev_io w, int revents) {
	client_t *client = w->data;
	int r = 0;
	char rbuff[1024];
	if (revents & EV_READ) {
	r = read(client->fd, &rbuff, 1024);
	}

	if (EV_ERROR & revents) {
	fprintf(stderr, "error event in read\n");
	free_res(loop, w);
	return ;
	}

	if (r < 0) {
	fprintf(stderr, "read error\n");
	ev_io_stop(EV_A_ w);
	free_res(loop, w);
	return;
	}

	if (r == 0) {
	fprintf(stderr, "client disconnected.\n");
	ev_io_stop(EV_A_ w);
	free_res(loop, w);
	return;
	}

	write_ori(client, HTMLFILE_RESPONSE_HEADER);

	char target_message[strlen(HTMLFILE_RESPONSE_FIRST) + 20];
	sprintf(target_message, "%X\r\n%s\r\n", (int)strlen(HTMLFILE_RESPONSE_FIRST), HTMLFILE_RESPONSE_FIRST);

	write_ori(client, target_message);

	client->timeout.data = client;
	ev_timer_init(&client->timeout, timeout_cb, 1.0, 1.0);
	ev_timer_start(loop, &client->timeout);
	}

	static void accept_cb(struct ev_loop loop, ev_io w, int revents) {
	struct sockaddr_in client_addr;
	socklen_t client_len = sizeof(client_addr);
	int client_fd = accept(w->fd, (struct sockaddr *) &client_addr, &client_len);
	if (client_fd == -1) {
	fprintf(stderr, "the client_fd is NULL !\n");
	return;
	}

	client_t *client = malloc(sizeof(client_t));
	client->fd = client_fd;
	if (setnonblock(client->fd) < 0)
	err(1, "failed to set client socket to non-blocking");

	client->ev_read.data = client;
	client->timeout.data = NULL;

	ev_io_init(&client->ev_read, read_cb, client->fd, EV_READ);
	ev_io_start(loop, &client->ev_read);
	}

	int main(int argc, char const *argv[]) {
	loop = ev_default_loop(0);
	struct sockaddr_in listen_addr;
	int reuseaddr_on = 1;
	int listen_fd = socket(AF_INET, SOCK_STREAM, 0);
	if (listen_fd < 0)
	err(1, "listen failed");
	if (setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr_on, sizeof(reuseaddr_on)) == -1)
	err(1, "setsockopt failed");

	memset(&listen_addr, 0, sizeof(listen_addr));
	listen_addr.sin_family = AF_INET;
	listen_addr.sin_addr.s_addr = INADDR_ANY;
	listen_addr.sin_port = htons(SERVER_PORT);

	if (bind(listen_fd, (struct sockaddr *) &listen_addr, sizeof(listen_addr)) < 0)
	err(1, "bind failed");
	if (listen(listen_fd, 5) < 0)
	err(1, "listen failed");
	if (setnonblock(listen_fd) < 0)
	err(1, "failed to set server socket to non-blocking");

	ev_io_init(&ev_accept, accept_cb, listen_fd, EV_READ);
	ev_io_start(loop, &ev_accept);
	ev_loop(loop, 0);

	return 0;
	}

	static void free_res(struct ev_loop loop, ev_io w) {
	client_t *client = w->data;
	if (client == NULL) {
	fprintf(stderr, "the client is NULL !!!!!!");
	return;
	}

	ev_io_stop(loop, &client->ev_read);

	ev_timer *timer = &client->timeout;
	if (timer != NULL && (timer->data != NULL)) {
	ev_timer_stop(loop, timer);
	}

	close(client->fd);

	free(client);
	}

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posted on 2013-03-28 08:41 nieyong 閱讀(2564) 評論(0) 編輯收藏所屬分類: socket.io

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c_socket.io_server筆記之htmlfile塊傳輸

關于htmlfile chunked傳輸

輸出頭部

傳輸部分HTML預備內容

設置定時器，周期性循環

編譯運行

完整代碼

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