1/*
2 * lws-minimal-http-server-form-post-file
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 performs POST with a couple
10 * of parameters and a file upload, all in multipart (mime) form mode.
11 * It saves the uploaded file in the current directory, dumps the parameters to
12 * the console log and redirects to another page.
13 */
14
15#include <libwebsockets.h>
16#include <string.h>
17#include <signal.h>
18#if !defined(WIN32)
19#include <unistd.h>
20#endif
21#include <fcntl.h>
22#include <stdlib.h>
23#include <errno.h>
24
25/*
26 * Unlike ws, http is a stateless protocol.  This pss only exists for the
27 * duration of a single http transaction.  With http/1.1 keep-alive and http/2,
28 * that is unrelated to (shorter than) the lifetime of the network connection.
29 */
30struct pss {
31	struct lws_spa *spa;		/* lws helper decodes multipart form */
32	char filename[128];		/* the filename of the uploaded file */
33	unsigned long long file_length; /* the amount of bytes uploaded */
34	int fd;				/* fd on file being saved */
35};
36
37static int interrupted;
38
39static const char * const param_names[] = {
40	"text1",
41	"send",
42};
43
44enum enum_param_names {
45	EPN_TEXT1,
46	EPN_SEND,
47};
48
49static int
50file_upload_cb(void *data, const char *name, const char *filename,
51	       char *buf, int len, enum lws_spa_fileupload_states state)
52{
53	struct pss *pss = (struct pss *)data;
54
55	switch (state) {
56	case LWS_UFS_OPEN:
57		/* take a copy of the provided filename */
58		lws_strncpy(pss->filename, filename, sizeof(pss->filename) - 1);
59		/* remove any scary things like .. */
60		lws_filename_purify_inplace(pss->filename);
61		/* open a file of that name for write in the cwd */
62		pss->fd = lws_open(pss->filename, O_CREAT | O_TRUNC | O_RDWR, 0600);
63		if (pss->fd == -1) {
64			lwsl_notice("Failed to open output file %s\n",
65				    pss->filename);
66			return 1;
67		}
68		break;
69	case LWS_UFS_FINAL_CONTENT:
70	case LWS_UFS_CONTENT:
71		if (len) {
72			int n;
73
74			pss->file_length += (unsigned int)len;
75
76			n = (int)write(pss->fd, buf, (unsigned int)len);
77			if (n < len) {
78				lwsl_notice("Problem writing file %d\n", errno);
79			}
80		}
81		if (state == LWS_UFS_CONTENT)
82			/* wasn't the last part of the file */
83			break;
84
85		/* the file upload is completed */
86
87		lwsl_user("%s: upload done, written %lld to %s\n", __func__,
88			  pss->file_length, pss->filename);
89
90		close(pss->fd);
91		pss->fd = -1;
92		break;
93	case LWS_UFS_CLOSE:
94		break;
95	}
96
97	return 0;
98}
99
100static int
101callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user,
102	      void *in, size_t len)
103{
104	uint8_t buf[LWS_PRE + LWS_RECOMMENDED_MIN_HEADER_SPACE], *start = &buf[LWS_PRE],
105		*p = start, *end = &buf[sizeof(buf) - 1];
106	struct pss *pss = (struct pss *)user;
107	int n;
108
109	switch (reason) {
110	case LWS_CALLBACK_HTTP:
111
112		/*
113		 * Manually report that our form target URL exists
114		 *
115		 * you can also do this by adding a mount for the form URL
116		 * to the protocol with type LWSMPRO_CALLBACK, then no need
117		 * to trap LWS_CALLBACK_HTTP.
118		 */
119
120		if (!strcmp((const char *)in, "/form1"))
121			/* assertively allow it to exist in the URL space */
122			return 0;
123
124		/* default to 404-ing the URL if not mounted */
125		break;
126
127	case LWS_CALLBACK_HTTP_BODY:
128
129		/* create the POST argument parser if not already existing */
130
131		if (!pss->spa) {
132			pss->spa = lws_spa_create(wsi, param_names,
133					LWS_ARRAY_SIZE(param_names), 1024,
134					file_upload_cb, pss);
135			if (!pss->spa)
136				return -1;
137		}
138
139		/* let it parse the POST data */
140
141		if (lws_spa_process(pss->spa, in, (int)len))
142			return -1;
143		break;
144
145	case LWS_CALLBACK_HTTP_BODY_COMPLETION:
146
147		/* inform the spa no more payload data coming */
148
149		lws_spa_finalize(pss->spa);
150
151		/* we just dump the decoded things to the log */
152
153		for (n = 0; n < (int)LWS_ARRAY_SIZE(param_names); n++) {
154			if (!lws_spa_get_string(pss->spa, n))
155				lwsl_user("%s: undefined\n", param_names[n]);
156			else
157				lwsl_user("%s: (len %d) '%s'\n",
158				    param_names[n],
159				    lws_spa_get_length(pss->spa, n),
160				    lws_spa_get_string(pss->spa, n));
161		}
162
163		/*
164		 * Our response is to redirect to a static page.  We could
165		 * have generated a dynamic html page here instead.
166		 */
167
168		if (lws_http_redirect(wsi, HTTP_STATUS_MOVED_PERMANENTLY,
169				      (unsigned char *)"after-form1.html",
170				      16, &p, end) < 0)
171			return -1;
172
173		break;
174
175	case LWS_CALLBACK_HTTP_DROP_PROTOCOL:
176		/* called when our wsi user_space is going to be destroyed */
177		if (pss->spa) {
178			lws_spa_destroy(pss->spa);
179			pss->spa = NULL;
180		}
181		break;
182
183	default:
184		break;
185	}
186
187	return lws_callback_http_dummy(wsi, reason, user, in, len);
188}
189
190static struct lws_protocols protocols[] = {
191	{ "http", callback_http, sizeof(struct pss), 0, 0, NULL, 0 },
192	LWS_PROTOCOL_LIST_TERM
193};
194
195/* default mount serves the URL space from ./mount-origin */
196
197static const struct lws_http_mount mount = {
198	/* .mount_next */	       NULL,		/* linked-list "next" */
199	/* .mountpoint */		"/",		/* mountpoint URL */
200	/* .origin */		"./mount-origin",	/* serve from dir */
201	/* .def */			"index.html",	/* default filename */
202	/* .protocol */			NULL,
203	/* .cgienv */			NULL,
204	/* .extra_mimetypes */		NULL,
205	/* .interpret */		NULL,
206	/* .cgi_timeout */		0,
207	/* .cache_max_age */		0,
208	/* .auth_mask */		0,
209	/* .cache_reusable */		0,
210	/* .cache_revalidate */		0,
211	/* .cache_intermediaries */	0,
212	/* .origin_protocol */		LWSMPRO_FILE,	/* files in a dir */
213	/* .mountpoint_len */		1,		/* char count */
214	/* .basic_auth_login_file */	NULL,
215};
216
217void sigint_handler(int sig)
218{
219	interrupted = 1;
220}
221
222int main(int argc, const char **argv)
223{
224	struct lws_context_creation_info info;
225	struct lws_context *context;
226	const char *p;
227	int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
228			/* for LLL_ verbosity above NOTICE to be built into lws,
229			 * lws must have been configured and built with
230			 * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
231			/* | LLL_INFO */ /* | LLL_PARSER */ /* | LLL_HEADER */
232			/* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
233			/* | LLL_DEBUG */;
234
235	signal(SIGINT, sigint_handler);
236
237	if ((p = lws_cmdline_option(argc, argv, "-d")))
238		logs = atoi(p);
239
240	lws_set_log_level(logs, NULL);
241	lwsl_user("LWS minimal http server POST file | visit http://localhost:7681\n");
242
243	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
244	info.port = 7681;
245	info.protocols = protocols;
246	info.mounts = &mount;
247	info.options =
248		LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
249
250	context = lws_create_context(&info);
251	if (!context) {
252		lwsl_err("lws init failed\n");
253		return 1;
254	}
255
256	while (n >= 0 && !interrupted)
257		n = lws_service(context, 0);
258
259	lws_context_destroy(context);
260
261	return 0;
262}
263