Home | History | Annotate | Download | only in examples 
      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel (at) 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, %lu bytes (0x%lx)\n",
     55           text, (unsigned long)size, (unsigned long)size);
     56 
     57   for(i = 0; i<size; i += width) {
     58 
     59     fprintf(stderr, "%4.4lx: ", (unsigned 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 int setup(CURL *hnd)
    132 {
    133   FILE *out = fopen(OUTPUTFILE, "wb");
    134   if(!out)
    135     /* failed */
    136     return 1;
    137 
    138   /* write to this file */
    139   curl_easy_setopt(hnd, CURLOPT_WRITEDATA, out);
    140 
    141   /* set the same URL */
    142   curl_easy_setopt(hnd, CURLOPT_URL, "https://localhost:8443/index.html");
    143 
    144   /* please be verbose */
    145   curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);
    146   curl_easy_setopt(hnd, CURLOPT_DEBUGFUNCTION, my_trace);
    147 
    148   /* HTTP/2 please */
    149   curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2_0);
    150 
    151   /* we use a self-signed test server, skip verification during debugging */
    152   curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYPEER, 0L);
    153   curl_easy_setopt(hnd, CURLOPT_SSL_VERIFYHOST, 0L);
    154 
    155 #if (CURLPIPE_MULTIPLEX > 0)
    156   /* wait for pipe connection to confirm */
    157   curl_easy_setopt(hnd, CURLOPT_PIPEWAIT, 1L);
    158 #endif
    159   return 0; /* all is good */
    160 }
    161 
    162 /* called when there's an incoming push */
    163 static int server_push_callback(CURL *parent,
    164                                 CURL *easy,
    165                                 size_t num_headers,
    166                                 struct curl_pushheaders *headers,
    167                                 void *userp)
    168 {
    169   char *headp;
    170   size_t i;
    171   int *transfers = (int *)userp;
    172   char filename[128];
    173   FILE *out;
    174   static unsigned int count = 0;
    175 
    176   (void)parent; /* we have no use for this */
    177 
    178   snprintf(filename, 128, "push%u", count++);
    179 
    180   /* here's a new stream, save it in a new file for each new push */
    181   out = fopen(filename, "wb");
    182   if(!out) {
    183     /* if we can't save it, deny it */
    184     fprintf(stderr, "Failed to create output file for push\n");
    185     return CURL_PUSH_DENY;
    186   }
    187 
    188   /* write to this file */
    189   curl_easy_setopt(easy, CURLOPT_WRITEDATA, out);
    190 
    191   fprintf(stderr, "**** push callback approves stream %u, got %lu headers!\n",
    192           count, (unsigned long)num_headers);
    193 
    194   for(i = 0; i<num_headers; i++) {
    195     headp = curl_pushheader_bynum(headers, i);
    196     fprintf(stderr, "**** header %lu: %s\n", (unsigned long)i, headp);
    197   }
    198 
    199   headp = curl_pushheader_byname(headers, ":path");
    200   if(headp) {
    201     fprintf(stderr, "**** The PATH is %s\n", headp /* skip :path + colon */);
    202   }
    203 
    204   (*transfers)++; /* one more */
    205   return CURL_PUSH_OK;
    206 }
    207 
    208 
    209 /*
    210  * Download a file over HTTP/2, take care of server push.
    211  */
    212 int main(void)
    213 {
    214   CURL *easy;
    215   CURLM *multi_handle;
    216   int still_running; /* keep number of running handles */
    217   int transfers = 1; /* we start with one */
    218   struct CURLMsg *m;
    219 
    220   /* init a multi stack */
    221   multi_handle = curl_multi_init();
    222 
    223   easy = curl_easy_init();
    224 
    225   /* set options */
    226   if(setup(easy)) {
    227     fprintf(stderr, "failed\n");
    228     return 1;
    229   }
    230 
    231   /* add the easy transfer */
    232   curl_multi_add_handle(multi_handle, easy);
    233 
    234   curl_multi_setopt(multi_handle, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
    235   curl_multi_setopt(multi_handle, CURLMOPT_PUSHFUNCTION, server_push_callback);
    236   curl_multi_setopt(multi_handle, CURLMOPT_PUSHDATA, &transfers);
    237 
    238   /* we start some action by calling perform right away */
    239   curl_multi_perform(multi_handle, &still_running);
    240 
    241   do {
    242     struct timeval timeout;
    243     int rc; /* select() return code */
    244     CURLMcode mc; /* curl_multi_fdset() return code */
    245 
    246     fd_set fdread;
    247     fd_set fdwrite;
    248     fd_set fdexcep;
    249     int maxfd = -1;
    250 
    251     long curl_timeo = -1;
    252 
    253     FD_ZERO(&fdread);
    254     FD_ZERO(&fdwrite);
    255     FD_ZERO(&fdexcep);
    256 
    257     /* set a suitable timeout to play around with */
    258     timeout.tv_sec = 1;
    259     timeout.tv_usec = 0;
    260 
    261     curl_multi_timeout(multi_handle, &curl_timeo);
    262     if(curl_timeo >= 0) {
    263       timeout.tv_sec = curl_timeo / 1000;
    264       if(timeout.tv_sec > 1)
    265         timeout.tv_sec = 1;
    266       else
    267         timeout.tv_usec = (curl_timeo % 1000) * 1000;
    268     }
    269 
    270     /* get file descriptors from the transfers */
    271     mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
    272 
    273     if(mc != CURLM_OK) {
    274       fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
    275       break;
    276     }
    277 
    278     /* On success the value of maxfd is guaranteed to be >= -1. We call
    279        select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
    280        no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
    281        to sleep 100ms, which is the minimum suggested value in the
    282        curl_multi_fdset() doc. */
    283 
    284     if(maxfd == -1) {
    285 #ifdef _WIN32
    286       Sleep(100);
    287       rc = 0;
    288 #else
    289       /* Portable sleep for platforms other than Windows. */
    290       struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
    291       rc = select(0, NULL, NULL, NULL, &wait);
    292 #endif
    293     }
    294     else {
    295       /* Note that on some platforms 'timeout' may be modified by select().
    296          If you need access to the original value save a copy beforehand. */
    297       rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
    298     }
    299 
    300     switch(rc) {
    301     case -1:
    302       /* select error */
    303       break;
    304     case 0:
    305     default:
    306       /* timeout or readable/writable sockets */
    307       curl_multi_perform(multi_handle, &still_running);
    308       break;
    309     }
    310 
    311     /*
    312      * A little caution when doing server push is that libcurl itself has
    313      * created and added one or more easy handles but we need to clean them up
    314      * when we are done.
    315      */
    316 
    317     do {
    318       int msgq = 0;;
    319       m = curl_multi_info_read(multi_handle, &msgq);
    320       if(m && (m->msg == CURLMSG_DONE)) {
    321         CURL *e = m->easy_handle;
    322         transfers--;
    323         curl_multi_remove_handle(multi_handle, e);
    324         curl_easy_cleanup(e);
    325       }
    326     } while(m);
    327 
    328   } while(transfers); /* as long as we have transfers going */
    329 
    330   curl_multi_cleanup(multi_handle);
    331 
    332 
    333   return 0;
    334 }
    335