curl/docs/examples/hiperfifo.c

   1 /*****************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * $Id: hiperfifo.c,v 1.7 2008-05-22 21:20:09 danf Exp $
   9  *
  10  * Example application source code using the multi socket interface to
  11  * download many files at once.
  12  *
  13  * Written by Jeff Pohlmeyer
  14
  15 Requires libevent and a (POSIX?) system that has mkfifo().
  16
  17 This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
  18 sample programs.
  19
  20 When running, the program creates the named pipe "hiper.fifo"
  21
  22 Whenever there is input into the fifo, the program reads the input as a list
  23 of URL's and creates some new easy handles to fetch each URL via the
  24 curl_multi "hiper" API.
  25
  26
  27 Thus, you can try a single URL:
  28   % echo http://www.yahoo.com > hiper.fifo
  29
  30 Or a whole bunch of them:
  31   % cat my-url-list > hiper.fifo
  32
  33 The fifo buffer is handled almost instantly, so you can even add more URL's
  34 while the previous requests are still being downloaded.
  35
  36 Note:
  37   For the sake of simplicity, URL length is limited to 1023 char's !
  38
  39 This is purely a demo app, all retrieved data is simply discarded by the write
  40 callback.
  41
  42 */
  43
  44 #include <stdio.h>
  45 #include <string.h>
  46 #include <stdlib.h>
  47 #include <sys/time.h>
  48 #include <time.h>
  49 #include <unistd.h>
  50 #include <sys/poll.h>
  51 #include <curl/curl.h>
  52 #include <event.h>
  53 #include <fcntl.h>
  54 #include <sys/stat.h>
  55 #include <errno.h>
  56
  57
  58 #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
  59
  60
  61 /* Global information, common to all connections */
  62 typedef struct _GlobalInfo {
  63   struct event fifo_event;
  64   struct event timer_event;
  65   CURLM *multi;
  66   int prev_running;
  67   int still_running;
  68   FILE* input;
  69 } GlobalInfo;
  70
  71
  72 /* Information associated with a specific easy handle */
  73 typedef struct _ConnInfo {
  74   CURL *easy;
  75   char *url;
  76   GlobalInfo *global;
  77   char error[CURL_ERROR_SIZE];
  78 } ConnInfo;
  79
  80
  81 /* Information associated with a specific socket */
  82 typedef struct _SockInfo {
  83   curl_socket_t sockfd;
  84   CURL *easy;
  85   int action;
  86   long timeout;
  87   struct event ev;
  88   int evset;
  89   GlobalInfo *global;
  90 } SockInfo;
  91
  92
  93
  94 /* Update the event timer after curl_multi library calls */
  95 static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
  96 {
  97   struct timeval timeout;
  98   (void)multi; /* unused */
  99
 100   timeout.tv_sec = timeout_ms/1000;
 101   timeout.tv_usec = (timeout_ms%1000)*1000;
 102   fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
 103   evtimer_add(&g->timer_event, &timeout);
 104   return 0;
 105 }
 106
 107 /* Die if we get a bad CURLMcode somewhere */
 108 static void mcode_or_die(const char *where, CURLMcode code)
 109 {
 110   if ( CURLM_OK != code ) {
 111     const char *s;
 112     switch (code) {
 113       case     CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
 114       case     CURLM_OK:                 s="CURLM_OK";                 break;
 115       case     CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
 116       case     CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
 117       case     CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;
 118       case     CURLM_INTERNAL_ERROR:     s="CURLM_INTERNAL_ERROR";     break;
 119       case     CURLM_UNKNOWN_OPTION:     s="CURLM_UNKNOWN_OPTION";     break;
 120       case     CURLM_LAST:               s="CURLM_LAST";               break;
 121       default: s="CURLM_unknown";
 122         break;
 123     case     CURLM_BAD_SOCKET:         s="CURLM_BAD_SOCKET";
 124       fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
 125       /* ignore this error */
 126       return;
 127     }
 128     fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
 129     exit(code);
 130   }
 131 }
 132
 133
 134
 135 /* Check for completed transfers, and remove their easy handles */
 136 static void check_run_count(GlobalInfo *g)
 137 {
 138   if (g->prev_running > g->still_running) {
 139     char *eff_url=NULL;
 140     CURLMsg *msg;
 141     int msgs_left;
 142     ConnInfo *conn=NULL;
 143     CURL*easy;
 144     CURLcode res;
 145
 146     fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
 147     /*
 148       I am still uncertain whether it is safe to remove an easy handle
 149       from inside the curl_multi_info_read loop, so here I will search
 150       for completed transfers in the inner "while" loop, and then remove
 151       them in the outer "do-while" loop...
 152    */
 153     do {
 154       easy=NULL;
 155       while ((msg = curl_multi_info_read(g->multi, &msgs_left))) {
 156         if (msg->msg == CURLMSG_DONE) {
 157           easy=msg->easy_handle;
 158           res=msg->data.result;
 159           break;
 160         }
 161       }
 162       if (easy) {
 163           curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
 164           curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
 165           fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
 166           curl_multi_remove_handle(g->multi, easy);
 167           free(conn->url);
 168           curl_easy_cleanup(easy);
 169           free(conn);
 170       }
 171     } while ( easy );
 172   }
 173   g->prev_running = g->still_running;
 174 }
 175
 176
 177
 178 /* Called by libevent when we get action on a multi socket */
 179 static void event_cb(int fd, short kind, void *userp)
 180 {
 181   GlobalInfo *g = (GlobalInfo*) userp;
 182   CURLMcode rc;
 183   (void)kind; /* unused */
 184
 185   do {
 186     rc = curl_multi_socket(g->multi, fd, &g->still_running);
 187   } while (rc == CURLM_CALL_MULTI_PERFORM);
 188   mcode_or_die("event_cb: curl_multi_socket", rc);
 189   check_run_count(g);
 190   if ( g->still_running <= 0 ) {
 191     fprintf(MSG_OUT, "last transfer done, kill timeout\n");
 192     if (evtimer_pending(&g->timer_event, NULL)) {
 193       evtimer_del(&g->timer_event);
 194     }
 195   }
 196 }
 197
 198
 199
 200 /* Called by libevent when our timeout expires */
 201 static void timer_cb(int fd, short kind, void *userp)
 202 {
 203   GlobalInfo *g = (GlobalInfo *)userp;
 204   CURLMcode rc;
 205   (void)fd;
 206   (void)kind;
 207
 208   do {
 209     rc = curl_multi_socket(g->multi, CURL_SOCKET_TIMEOUT, &g->still_running);
 210   } while (rc == CURLM_CALL_MULTI_PERFORM);
 211   mcode_or_die("timer_cb: curl_multi_socket", rc);
 212   check_run_count(g);
 213 }
 214
 215
 216
 217 /* Clean up the SockInfo structure */
 218 static void remsock(SockInfo *f)
 219 {
 220   if (f) {
 221     if (f->evset)
 222       event_del(&f->ev);
 223     free(f);
 224   }
 225 }
 226
 227
 228
 229 /* Assign information to a SockInfo structure */
 230 static void setsock(SockInfo*f, curl_socket_t s, CURL*e, int act, GlobalInfo*g)
 231 {
 232   int kind =
 233      (act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST;
 234
 235   f->sockfd = s;
 236   f->action = act;
 237   f->easy = e;
 238   if (f->evset)
 239     event_del(&f->ev);
 240   event_set(&f->ev, f->sockfd, kind, event_cb, g);
 241   f->evset=1;
 242   event_add(&f->ev, NULL);
 243 }
 244
 245
 246
 247 /* Initialize a new SockInfo structure */
 248 static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g) {
 249   SockInfo *fdp = calloc(sizeof(SockInfo), 1);
 250
 251   fdp->global = g;
 252   setsock(fdp, s, easy, action, g);
 253   curl_multi_assign(g->multi, s, fdp);
 254 }
 255
 256 /* CURLMOPT_SOCKETFUNCTION */
 257 static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
 258 {
 259   GlobalInfo *g = (GlobalInfo*) cbp;
 260   SockInfo *fdp = (SockInfo*) sockp;
 261   const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
 262
 263   fprintf(MSG_OUT,
 264           "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
 265   if (what == CURL_POLL_REMOVE) {
 266     fprintf(MSG_OUT, "\n");
 267     remsock(fdp);
 268   }
 269   else {
 270     if (!fdp) {
 271       fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
 272       addsock(s, e, what, g);
 273     }
 274     else {
 275       fprintf(MSG_OUT,
 276               "Changing action from %s to %s\n",
 277               whatstr[fdp->action], whatstr[what]);
 278       setsock(fdp, s, e, what, g);
 279     }
 280   }
 281   return 0;
 282 }
 283
 284
 285
 286 /* CURLOPT_WRITEFUNCTION */
 287 static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
 288 {
 289   size_t realsize = size * nmemb;
 290   ConnInfo *conn = (ConnInfo*) data;
 291   (void)ptr;
 292   (void)conn;
 293   return realsize;
 294 }
 295
 296
 297 /* CURLOPT_PROGRESSFUNCTION */
 298 static int prog_cb (void *p, double dltotal, double dlnow, double ult,
 299                     double uln)
 300 {
 301   ConnInfo *conn = (ConnInfo *)p;
 302   (void)ult;
 303   (void)uln;
 304
 305   fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
 306   return 0;
 307 }
 308
 309
 310 /* Create a new easy handle, and add it to the global curl_multi */
 311 static void new_conn(char *url, GlobalInfo *g )
 312 {
 313   ConnInfo *conn;
 314   CURLMcode rc;
 315
 316   conn = calloc(1, sizeof(ConnInfo));
 317   memset(conn, 0, sizeof(ConnInfo));
 318   conn->error[0]='\0';
 319
 320   conn->easy = curl_easy_init();
 321   if (!conn->easy) {
 322     fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
 323     exit(2);
 324   }
 325   conn->global = g;
 326   conn->url = strdup(url);
 327   curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
 328   curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
 329   curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
 330   curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
 331   curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
 332   curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
 333   curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
 334   curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
 335   curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
 336   fprintf(MSG_OUT,
 337           "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
 338   rc =curl_multi_add_handle(g->multi, conn->easy);
 339   mcode_or_die("new_conn: curl_multi_add_handle", rc);
 340   do {
 341     rc = curl_multi_socket_all(g->multi, &g->still_running);
 342   } while (CURLM_CALL_MULTI_PERFORM == rc);
 343   mcode_or_die("new_conn: curl_multi_socket_all", rc);
 344   check_run_count(g);
 345 }
 346
 347 /* This gets called whenever data is received from the fifo */
 348 static void fifo_cb(int fd, short event, void *arg)
 349 {
 350   char s[1024];
 351   long int rv=0;
 352   int n=0;
 353   GlobalInfo *g = (GlobalInfo *)arg;
 354   (void)fd; /* unused */
 355   (void)event; /* unused */
 356
 357   do {
 358     s[0]='\0';
 359     rv=fscanf(g->input, "%1023s%n", s, &n);
 360     s[n]='\0';
 361     if ( n && s[0] ) {
 362       new_conn(s,arg);  /* if we read a URL, go get it! */
 363     } else break;
 364   } while ( rv != EOF);
 365 }
 366
 367 /* Create a named pipe and tell libevent to monitor it */
 368 static int init_fifo (GlobalInfo *g)
 369 {
 370   struct stat st;
 371   static const char *fifo = "hiper.fifo";
 372   int sockfd;
 373
 374   fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
 375   if (lstat (fifo, &st) == 0) {
 376     if ((st.st_mode & S_IFMT) == S_IFREG) {
 377       errno = EEXIST;
 378       perror("lstat");
 379       exit (1);
 380     }
 381   }
 382   unlink(fifo);
 383   if (mkfifo (fifo, 0600) == -1) {
 384     perror("mkfifo");
 385     exit (1);
 386   }
 387   sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
 388   if (sockfd == -1) {
 389     perror("open");
 390     exit (1);
 391   }
 392   g->input = fdopen(sockfd, "r");
 393
 394   fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
 395   event_set(&g->fifo_event, sockfd, EV_READ | EV_PERSIST, fifo_cb, g);
 396   event_add(&g->fifo_event, NULL);
 397   return (0);
 398 }
 399
 400 int main(int argc, char **argv)
 401 {
 402   GlobalInfo g;
 403   CURLMcode rc;
 404   (void)argc;
 405   (void)argv;
 406
 407   memset(&g, 0, sizeof(GlobalInfo));
 408   event_init();
 409   init_fifo(&g);
 410   g.multi = curl_multi_init();
 411   evtimer_set(&g.timer_event, timer_cb, &g);
 412   curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
 413   curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
 414   curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
 415   curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
 416   do {
 417     rc = curl_multi_socket_all(g.multi, &g.still_running);
 418   } while (CURLM_CALL_MULTI_PERFORM == rc);
 419   event_dispatch();
 420   curl_multi_cleanup(g.multi);
 421   return 0;
 422 }