Annotation of embedaddon/curl/docs/examples/http2-serverpush.c, revision 1.1.1.1

1.1       misho       1: /***************************************************************************
                      2:  *                                  _   _ ____  _
                      3:  *  Project                     ___| | | |  _ \| |
                      4:  *                             / __| | | | |_) | |
                      5:  *                            | (__| |_| |  _ <| |___
                      6:  *                             \___|\___/|_| \_\_____|
                      7:  *
                      8:  * Copyright (C) 1998 - 2019, 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, %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: }

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