1/*
2 * lws-minimal-http-server-sse
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 a minimal http server that can serve both normal static
10 * content and server-side event connections.
11 *
12 * To keep it simple, it serves the static stuff from the subdirectory
13 * "./mount-origin" of the directory it was started in.
14 *
15 * You can change that by changing mount.origin below.
16 */
17
18#include <libwebsockets.h>
19#include <string.h>
20#include <signal.h>
21#include <time.h>
22#if defined(WIN32)
23#define HAVE_STRUCT_TIMESPEC
24#if defined(pid_t)
25#undef pid_t
26#endif
27#endif
28#include <pthread.h>
29
30/*
31 * Unlike ws, http is a stateless protocol.  This pss only exists for the
32 * duration of a single http transaction.  With http/1.1 keep-alive and http/2,
33 * that is unrelated to (shorter than) the lifetime of the network connection.
34 */
35struct pss {
36	time_t established;
37};
38
39static int interrupted;
40
41#define SECS_REPORT 3
42
43static int
44callback_sse(struct lws *wsi, enum lws_callback_reasons reason, void *user,
45	     void *in, size_t len)
46{
47	struct pss *pss = (struct pss *)user;
48	uint8_t buf[LWS_PRE + LWS_RECOMMENDED_MIN_HEADER_SPACE], *start = &buf[LWS_PRE],
49		*p = start, *end = &buf[sizeof(buf) - 1];
50
51	switch (reason) {
52	case LWS_CALLBACK_HTTP:
53		/*
54		 * `in` contains the url part after our mountpoint /sse, if any
55		 * you can use this to determine what data to return and store
56		 * that in the pss
57		 */
58		lwsl_notice("%s: LWS_CALLBACK_HTTP: '%s'\n", __func__,
59			    (const char *)in);
60
61		pss->established = time(NULL);
62
63		/* SSE requires a response with this content-type */
64
65		if (lws_add_http_common_headers(wsi, HTTP_STATUS_OK,
66						"text/event-stream",
67						LWS_ILLEGAL_HTTP_CONTENT_LEN,
68						&p, end))
69			return 1;
70
71		if (lws_finalize_write_http_header(wsi, start, &p, end))
72			return 1;
73
74		/*
75		 * This tells lws we are no longer a normal http stream,
76		 * but are an "immortal" (plus or minus whatever timeout you
77		 * set on it afterwards) SSE stream.  In http/2 case that also
78		 * stops idle timeouts being applied to the network connection
79		 * while this wsi is still open.
80		 */
81		lws_http_mark_sse(wsi);
82
83		/* write the body separately */
84
85		lws_callback_on_writable(wsi);
86
87		return 0;
88
89	case LWS_CALLBACK_HTTP_WRITEABLE:
90
91		lwsl_notice("%s: LWS_CALLBACK_HTTP_WRITEABLE\n", __func__);
92
93		if (!pss)
94			break;
95
96		/*
97		 * to keep this demo as simple as possible, each client has his
98		 * own private data and timer.
99		 */
100
101		p += lws_snprintf((char *)p, lws_ptr_diff_size_t(end, p),
102				  "data: %llu\x0d\x0a\x0d\x0a",
103				  (unsigned long long)(time(NULL) -
104				  pss->established));
105
106		if (lws_write(wsi, (uint8_t *)start, lws_ptr_diff_size_t(p, start),
107			      LWS_WRITE_HTTP) != lws_ptr_diff(p, start))
108			return 1;
109
110		lws_set_timer_usecs(wsi, SECS_REPORT * LWS_USEC_PER_SEC);
111
112		return 0;
113
114	case LWS_CALLBACK_TIMER:
115
116		lwsl_notice("%s: LWS_CALLBACK_TIMER\n", __func__);
117		lws_callback_on_writable(wsi);
118
119		return 0;
120
121	default:
122		break;
123	}
124
125	return lws_callback_http_dummy(wsi, reason, user, in, len);
126}
127
128static struct lws_protocols protocols[] = {
129	{ "http", lws_callback_http_dummy, 0, 0, 0, NULL, 0 },
130	{ "sse", callback_sse, sizeof(struct pss), 0, 0, NULL, 0 },
131	LWS_PROTOCOL_LIST_TERM
132};
133
134/* override the default mount for /sse in the URL space */
135
136static const struct lws_http_mount mount_sse = {
137	/* .mount_next */		NULL,		/* linked-list "next" */
138	/* .mountpoint */		"/sse",		/* mountpoint URL */
139	/* .origin */			NULL,		/* protocol */
140	/* .def */			NULL,
141	/* .protocol */			"sse",
142	/* .cgienv */			NULL,
143	/* .extra_mimetypes */		NULL,
144	/* .interpret */		NULL,
145	/* .cgi_timeout */		0,
146	/* .cache_max_age */		0,
147	/* .auth_mask */		0,
148	/* .cache_reusable */		0,
149	/* .cache_revalidate */		0,
150	/* .cache_intermediaries */	0,
151	/* .origin_protocol */		LWSMPRO_CALLBACK, /* dynamic */
152	/* .mountpoint_len */		4,		  /* char count */
153	/* .basic_auth_login_file */	NULL,
154};
155
156/* default mount serves the URL space from ./mount-origin */
157
158static const struct lws_http_mount mount = {
159	/* .mount_next */		&mount_sse,	/* linked-list "next" */
160	/* .mountpoint */		"/",		/* mountpoint URL */
161	/* .origin */			"./mount-origin", /* serve from dir */
162	/* .def */			"index.html",	/* default filename */
163	/* .protocol */			NULL,
164	/* .cgienv */			NULL,
165	/* .extra_mimetypes */		NULL,
166	/* .interpret */		NULL,
167	/* .cgi_timeout */		0,
168	/* .cache_max_age */		0,
169	/* .auth_mask */		0,
170	/* .cache_reusable */		0,
171	/* .cache_revalidate */		0,
172	/* .cache_intermediaries */	0,
173	/* .origin_protocol */		LWSMPRO_FILE,	/* files in a dir */
174	/* .mountpoint_len */		1,		/* char count */
175	/* .basic_auth_login_file */	NULL,
176};
177
178void sigint_handler(int sig)
179{
180	interrupted = 1;
181}
182
183int main(int argc, const char **argv)
184{
185	struct lws_context_creation_info info;
186	struct lws_context *context;
187	const char *p;
188	int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
189			/* for LLL_ verbosity above NOTICE to be built into lws,
190			 * lws must have been configured and built with
191			 * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
192			/* | LLL_INFO */ /* | LLL_PARSER */ /* | LLL_HEADER */
193			/* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
194			/* | LLL_DEBUG */;
195
196	signal(SIGINT, sigint_handler);
197
198	if ((p = lws_cmdline_option(argc, argv, "-d")))
199		logs = atoi(p);
200
201	lws_set_log_level(logs, NULL);
202	lwsl_user("LWS minimal http Server-Side Events | visit http://localhost:7681\n");
203
204	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
205
206	info.protocols = protocols;
207	info.mounts = &mount;
208	info.options =
209		LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
210	info.port = 7681;
211
212#if defined(LWS_WITH_TLS)
213	if (lws_cmdline_option(argc, argv, "-s")) {
214		info.port = 443;
215		info.options |= LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
216		info.ssl_cert_filepath = "localhost-100y.cert";
217		info.ssl_private_key_filepath = "localhost-100y.key";
218	}
219#endif
220
221	context = lws_create_context(&info);
222	if (!context) {
223		lwsl_err("lws init failed\n");
224		return 1;
225	}
226
227	while (n >= 0 && !interrupted)
228		n = lws_service(context, 0);
229
230	lws_context_destroy(context);
231
232	return 0;
233}
234