1/*
2 * lws-minimal-http-server-h2-long-poll
3 *
4 * Written in 2010-2019 by Andy Green <andy@warmcat.com>
5 *
6 * This file is made available under the Creative Commons CC0 1.0
7 * Universal Public Domain Dedication.
8 *
9 * This demonstrates an h2 server that supports "long poll"
10 * immortal client connections.  For simplicity it doesn't serve
11 * any regular files, you can add a mount to do it if you want.
12 *
13 * The protocol keeps the long poll h2 stream open, and sends
14 * the time on the stream once per minute.  Normally idle h2
15 * connections are closed by default within 30s, so this demonstrates
16 * the stream and network connection are operating as "immortal"
17 * on both sides.
18 *
19 * See http-client/minimal-http-client-h2-long-poll for the
20 * client example that connects and transitions the stream to the
21 * immortal long poll mode.
22 */
23
24#include <libwebsockets.h>
25#include <string.h>
26#include <signal.h>
27
28static int interrupted;
29
30struct pss {
31	struct lws *wsi;
32	lws_sorted_usec_list_t sul;
33	char pending;
34};
35
36static const lws_retry_bo_t retry = {
37	.secs_since_valid_ping = 5,
38	.secs_since_valid_hangup = 10,
39};
40
41static void
42sul_cb(lws_sorted_usec_list_t *sul)
43{
44	struct pss *pss = (struct pss *)lws_container_of(sul, struct pss, sul);
45
46	pss->pending = 1;
47	lws_callback_on_writable(pss->wsi);
48	/* interval 1min... longer than any normal timeout */
49	lws_sul_schedule(lws_get_context(pss->wsi), 0, &pss->sul, sul_cb,
50				60 * LWS_US_PER_SEC);
51}
52
53static int
54callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user,
55	      void *in, size_t len)
56{
57	struct pss * pss = (struct pss *)user;
58	uint8_t buf[LWS_PRE + LWS_RECOMMENDED_MIN_HEADER_SPACE],
59		*start = &buf[LWS_PRE], *p = start,
60		*end = buf + sizeof(buf) - 1;
61	int m, n;
62
63	switch (reason) {
64	case LWS_CALLBACK_HTTP:
65		lwsl_user("%s: connect\n", __func__);
66		pss->wsi = wsi;
67
68		if (lws_add_http_common_headers(wsi, HTTP_STATUS_OK,
69				"text/html",
70				LWS_ILLEGAL_HTTP_CONTENT_LEN, /* no content len */
71				&p, end))
72			return 1;
73		if (lws_finalize_write_http_header(wsi, start, &p, end))
74			return 1;
75
76		sul_cb(&pss->sul);
77		return 0;
78
79	case LWS_CALLBACK_CLOSED_HTTP:
80		if (!pss)
81			break;
82		lws_sul_cancel(&pss->sul);
83		break;
84
85	case LWS_CALLBACK_HTTP_WRITEABLE:
86		if (!pss->pending)
87			break;
88		n = lws_snprintf((char *)p, sizeof(buf) - LWS_PRE, "%llu",
89				 (unsigned long long)lws_now_usecs());
90		m = lws_write(wsi, p, (unsigned int)n, LWS_WRITE_HTTP);
91		if (m < n) {
92			lwsl_err("ERROR %d writing to socket\n", n);
93			return -1;
94		}
95		break;
96	default:
97		break;
98	}
99
100	return lws_callback_http_dummy(wsi, reason, user, in, len);
101}
102
103static struct lws_protocols protocols[] = {
104	{ "http", callback_http, sizeof(struct pss), 0, 0, NULL, 0 },
105	LWS_PROTOCOL_LIST_TERM
106};
107
108
109void sigint_handler(int sig)
110{
111	interrupted = 1;
112}
113
114int main(int argc, const char **argv)
115{
116	struct lws_context_creation_info info;
117	struct lws_context *context;
118	const char *p;
119	int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE;
120
121	signal(SIGINT, sigint_handler);
122
123	if ((p = lws_cmdline_option(argc, argv, "-d")))
124		logs = atoi(p);
125
126	lws_set_log_level(logs, NULL);
127	lwsl_user("LWS minimal http server h2 long poll\n");
128
129	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
130	info.port = 7681;
131#if defined(LWS_WITH_TLS)
132	info.ssl_cert_filepath = "localhost-100y.cert";
133	info.ssl_private_key_filepath = "localhost-100y.key";
134#endif
135	info.protocols = protocols;
136	info.options =
137		LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT |
138		LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL |
139		LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
140
141	/* the default validity check is 5m / 5m10s... -v = 5s / 10s */
142
143	if (lws_cmdline_option(argc, argv, "-v"))
144		info.retry_and_idle_policy = &retry;
145
146	context = lws_create_context(&info);
147	if (!context) {
148		lwsl_err("lws init failed\n");
149		return 1;
150	}
151
152	while (n >= 0 && !interrupted)
153		n = lws_service(context, 0);
154
155	lws_context_destroy(context);
156
157	return 0;
158}
159