1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
11  * you should have received as part of this distribution. The terms
12  * are also available at https://curl.haxx.se/docs/copyright.html.
13  *
14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15  * copies of the Software, and permit persons to whom the Software is
16  * furnished to do so, under the terms of the COPYING file.
17  *
18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  ***************************************************************************/
22 /* <DESC>
23  * HTTP/2 server push
24  * </DESC>
25  */
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 
30 /* somewhat unix-specific */
31 #include <sys/time.h>
32 #include <unistd.h>
33 
34 /* curl stuff */
35 #include <curl/curl.h>
36 
37 #ifndef CURLPIPE_MULTIPLEX
38 #error "too old libcurl, can't do HTTP/2 server push!"
39 #endif
40 
41 static
42 void dump(const char *text, unsigned char *ptr, size_t size,
43           char nohex)
44 {
45   size_t i;
46   size_t c;
47 
48   unsigned int width = 0x10;
49 
50   if(nohex)
51     /* without the hex output, we can fit more on screen */
52     width = 0x40;
53 
54   fprintf(stderr, "%s, %ld bytes (0x%lx)\n",
55           text, (long)size, (long)size);
56 
57   for(i = 0; i<size; i += width) {
58 
59     fprintf(stderr, "%4.4lx: ", (long)i);
60 
61     if(!nohex) {
62       /* hex not disabled, show it */
63       for(c = 0; c < width; c++)
64         if(i + c < size)
65           fprintf(stderr, "%02x ", ptr[i + c]);
66         else
67           fputs("   ", stderr);
68     }
69 
70     for(c = 0; (c < width) && (i + c < size); c++) {
71       /* check for 0D0A; if found, skip past and start a new line of output */
72       if(nohex && (i + c + 1 < size) && ptr[i + c] == 0x0D &&
73          ptr[i + c + 1] == 0x0A) {
74         i += (c + 2 - width);
75         break;
76       }
77       fprintf(stderr, "%c",
78               (ptr[i + c] >= 0x20) && (ptr[i + c]<0x80)?ptr[i + c]:'.');
79       /* check again for 0D0A, to avoid an extra \n if it's at width */
80       if(nohex && (i + c + 2 < size) && ptr[i + c + 1] == 0x0D &&
81          ptr[i + c + 2] == 0x0A) {
82         i += (c + 3 - width);
83         break;
84       }
85     }
86     fputc('\n', stderr); /* newline */
87   }
88 }
89 
90 static
91 int my_trace(CURL *handle, curl_infotype type,
92              char *data, size_t size,
93              void *userp)
94 {
95   const char *text;
96   (void)handle; /* prevent compiler warning */
97   (void)userp;
98   switch(type) {
99   case CURLINFO_TEXT:
100     fprintf(stderr, "== Info: %s", data);
101     /* FALLTHROUGH */
102   default: /* in case a new one is introduced to shock us */
103     return 0;
104 
105   case CURLINFO_HEADER_OUT:
106     text = "=> Send header";
107     break;
108   case CURLINFO_DATA_OUT:
109     text = "=> Send data";
110     break;
111   case CURLINFO_SSL_DATA_OUT:
112     text = "=> Send SSL data";
113     break;
114   case CURLINFO_HEADER_IN:
115     text = "<= Recv header";
116     break;
117   case CURLINFO_DATA_IN:
118     text = "<= Recv data";
119     break;
120   case CURLINFO_SSL_DATA_IN:
121     text = "<= Recv SSL data";
122     break;
123   }
124 
125   dump(text, (unsigned char *)data, size, 1);
126   return 0;
127 }
128 
129 #define OUTPUTFILE "dl"
130 
131 static void setup(CURL *hnd)
132 {
133   FILE *out = fopen(OUTPUTFILE, "wb");
134 
135   /* write to this file */
136   curl_easy_setopt(hnd, CURLOPT_WRITEDATA, out);
137 
138   /* set the same URL */
139   curl_easy_setopt(hnd, CURLOPT_URL, "https://localhost:8443/index.html");
140 
141   /* please be verbose */
142   curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);
143   curl_easy_setopt(hnd, CURLOPT_DEBUGFUNCTION, my_trace);
144 
145   /* HTTP/2 please */
146   curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2_0);
147 
148   /* we use a self-signed test server, skip verification during debugging */
149   curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYPEER, 0L);
150   curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYHOST, 0L);
151 
152 #if (CURLPIPE_MULTIPLEX > 0)
153   /* wait for pipe connection to confirm */
154   curl_easy_setopt(hnd, CURLOPT_PIPEWAIT, 1L);
155 #endif
156 
157 }
158 
159 /* called when there's an incoming push */
160 static int server_push_callback(CURL *parent,
161                                 CURL *easy,
162                                 size_t num_headers,
163                                 struct curl_pushheaders *headers,
164                                 void *userp)
165 {
166   char *headp;
167   size_t i;
168   int *transfers = (int *)userp;
169   char filename[128];
170   FILE *out;
171   static unsigned int count = 0;
172 
173   (void)parent; /* we have no use for this */
174 
175   snprintf(filename, 128, "push%u", count++);
176 
177   /* here's a new stream, save it in a new file for each new push */
178   out = fopen(filename, "wb");
179 
180   /* write to this file */
181   curl_easy_setopt(easy, CURLOPT_WRITEDATA, out);
182 
183   fprintf(stderr, "**** push callback approves stream %u, got %d headers!\n",
184           count, (int)num_headers);
185 
186   for(i = 0; i<num_headers; i++) {
187     headp = curl_pushheader_bynum(headers, i);
188     fprintf(stderr, "**** header %u: %s\n", (int)i, headp);
189   }
190 
191   headp = curl_pushheader_byname(headers, ":path");
192   if(headp) {
193     fprintf(stderr, "**** The PATH is %s\n", headp /* skip :path + colon */);
194   }
195 
196   (*transfers)++; /* one more */
197   return CURL_PUSH_OK;
198 }
199 
200 
201 /*
202  * Download a file over HTTP/2, take care of server push.
203  */
204 int main(void)
205 {
206   CURL *easy;
207   CURLM *multi_handle;
208   int still_running; /* keep number of running handles */
209   int transfers = 1; /* we start with one */
210   struct CURLMsg *m;
211 
212   /* init a multi stack */
213   multi_handle = curl_multi_init();
214 
215   easy = curl_easy_init();
216 
217   /* set options */
218   setup(easy);
219 
220   /* add the easy transfer */
221   curl_multi_add_handle(multi_handle, easy);
222 
223   curl_multi_setopt(multi_handle, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
224   curl_multi_setopt(multi_handle, CURLMOPT_PUSHFUNCTION, server_push_callback);
225   curl_multi_setopt(multi_handle, CURLMOPT_PUSHDATA, &transfers);
226 
227   /* we start some action by calling perform right away */
228   curl_multi_perform(multi_handle, &still_running);
229 
230   do {
231     struct timeval timeout;
232     int rc; /* select() return code */
233     CURLMcode mc; /* curl_multi_fdset() return code */
234 
235     fd_set fdread;
236     fd_set fdwrite;
237     fd_set fdexcep;
238     int maxfd = -1;
239 
240     long curl_timeo = -1;
241 
242     FD_ZERO(&fdread);
243     FD_ZERO(&fdwrite);
244     FD_ZERO(&fdexcep);
245 
246     /* set a suitable timeout to play around with */
247     timeout.tv_sec = 1;
248     timeout.tv_usec = 0;
249 
250     curl_multi_timeout(multi_handle, &curl_timeo);
251     if(curl_timeo >= 0) {
252       timeout.tv_sec = curl_timeo / 1000;
253       if(timeout.tv_sec > 1)
254         timeout.tv_sec = 1;
255       else
256         timeout.tv_usec = (curl_timeo % 1000) * 1000;
257     }
258 
259     /* get file descriptors from the transfers */
260     mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
261 
262     if(mc != CURLM_OK) {
263       fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
264       break;
265     }
266 
267     /* On success the value of maxfd is guaranteed to be >= -1. We call
268        select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
269        no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
270        to sleep 100ms, which is the minimum suggested value in the
271        curl_multi_fdset() doc. */
272 
273     if(maxfd == -1) {
274 #ifdef _WIN32
275       Sleep(100);
276       rc = 0;
277 #else
278       /* Portable sleep for platforms other than Windows. */
279       struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
280       rc = select(0, NULL, NULL, NULL, &wait);
281 #endif
282     }
283     else {
284       /* Note that on some platforms 'timeout' may be modified by select().
285          If you need access to the original value save a copy beforehand. */
286       rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
287     }
288 
289     switch(rc) {
290     case -1:
291       /* select error */
292       break;
293     case 0:
294     default:
295       /* timeout or readable/writable sockets */
296       curl_multi_perform(multi_handle, &still_running);
297       break;
298     }
299 
300     /*
301      * A little caution when doing server push is that libcurl itself has
302      * created and added one or more easy handles but we need to clean them up
303      * when we are done.
304      */
305 
306     do {
307       int msgq = 0;;
308       m = curl_multi_info_read(multi_handle, &msgq);
309       if(m && (m->msg == CURLMSG_DONE)) {
310         CURL *e = m->easy_handle;
311         transfers--;
312         curl_multi_remove_handle(multi_handle, e);
313         curl_easy_cleanup(e);
314       }
315     } while(m);
316 
317   } while(transfers); /* as long as we have transfers going */
318 
319   curl_multi_cleanup(multi_handle);
320 
321 
322   return 0;
323 }
324