/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2017, Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ /* * multi socket API usage with libevent 2 * */ /* Example application source code using the multi socket interface to download many files at once. Written by Jeff Pohlmeyer Requires libevent version 2 and a (POSIX?) system that has mkfifo(). This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c" sample programs. When running, the program creates the named pipe "hiper.fifo" Whenever there is input into the fifo, the program reads the input as a list of URL's and creates some new easy handles to fetch each URL via the curl_multi "hiper" API. Thus, you can try a single URL: % echo http://www.yahoo.com > hiper.fifo Or a whole bunch of them: % cat my-url-list > hiper.fifo The fifo buffer is handled almost instantly, so you can even add more URL's while the previous requests are still being downloaded. Note: For the sake of simplicity, URL length is limited to 1023 char's ! This is purely a demo app, all retrieved data is simply discarded by the write callback. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __GNUC__ #define _Unused __attribute__((unused)) #else #define _Unused #endif #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */ /* Global information, common to all connections */ typedef struct _GlobalInfo { struct event_base *evbase; struct event timer_event; CURLM *multi; int still_running; FILE *input; } GlobalInfo; /* Information associated with a specific easy handle */ typedef struct _ConnInfo { CURL *easy; char *url; GlobalInfo *global; char error[CURL_ERROR_SIZE]; struct event periodic; struct { char *mem; unsigned size; unsigned base; unsigned avail; } buffer; int paused; } ConnInfo; /* Information associated with a specific socket */ typedef struct _SockInfo { curl_socket_t sockfd; CURL *easy; int action; long timeout; struct event ev; GlobalInfo *global; } SockInfo; #define BUFFER_SIZE 2097152 #define __case(code) \ case code: s = __STRING(code) /* Die if we get a bad CURLMcode somewhere */ static void mcode_or_die(const char *where, CURLMcode code) { if(CURLM_OK != code) { const char *s; switch(code) { __case(CURLM_BAD_HANDLE); break; __case(CURLM_BAD_EASY_HANDLE); break; __case(CURLM_OUT_OF_MEMORY); break; __case(CURLM_INTERNAL_ERROR); break; __case(CURLM_UNKNOWN_OPTION); break; __case(CURLM_LAST); break; default: s = "CURLM_unknown"; break; __case(CURLM_BAD_SOCKET); fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s); /* ignore this error */ return; } fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s); exit(code); } } /* Update the event timer after curl_multi library calls */ static int multi_timer_cb(CURLM *multi _Unused, long timeout_ms, GlobalInfo *g) { struct timeval timeout; CURLMcode rc; timeout.tv_sec = timeout_ms/1000; timeout.tv_usec = (timeout_ms%1000)*1000; fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms); /* TODO * * if timeout_ms is 0, call curl_multi_socket_action() at once! * * if timeout_ms is -1, just delete the timer * * for all other values of timeout_ms, this should set or *update* * the timer to the new value */ if (timeout_ms == 0) { rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running); mcode_or_die("multi_timer_cb: curl_multi_socket_action", rc); } else if (timeout_ms == -1) evtimer_del(&g->timer_event); else evtimer_add(&g->timer_event, &timeout); return 0; } /* Check for completed transfers, and remove their easy handles */ static void check_multi_info(GlobalInfo *g) { char *eff_url; CURLMsg *msg; int msgs_left; ConnInfo *conn; CURL *easy; CURLcode res; fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running); while((msg = curl_multi_info_read(g->multi, &msgs_left))) { if(msg->msg == CURLMSG_DONE) { easy = msg->easy_handle; res = msg->data.result; curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn); curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url); fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error); curl_multi_remove_handle(g->multi, easy); free(conn->url); curl_easy_cleanup(easy); free(conn->buffer.mem); event_del(&conn->periodic); free(conn); } } } /* Called by libevent when we get action on a multi socket */ static void event_cb(int fd, short kind, void *userp) { GlobalInfo *g = (GlobalInfo*) userp; CURLMcode rc; int action = (kind & EV_READ ? CURL_CSELECT_IN : 0) | (kind & EV_WRITE ? CURL_CSELECT_OUT : 0); rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running); mcode_or_die("event_cb: curl_multi_socket_action", rc); check_multi_info(g); if(g->still_running <= 0) { fprintf(MSG_OUT, "last transfer done, kill timeout\n"); if(evtimer_pending(&g->timer_event, NULL)) { evtimer_del(&g->timer_event); } } } /* Called by libevent when our timeout expires */ static void timer_cb(int fd _Unused, short kind _Unused, void *userp) { GlobalInfo *g = (GlobalInfo *)userp; CURLMcode rc; rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running); mcode_or_die("timer_cb: curl_multi_socket_action", rc); check_multi_info(g); } /* Called by libevent for our periodic timers */ static void periodic_cb(int fd _Unused, short kind _Unused, void *userp) { ConnInfo *conn = (ConnInfo *)userp; unsigned want = random() % (256 * 1024); fprintf(stderr, "tick: want %u bytes (avail %u)\n", want, conn->buffer.avail); if (want > conn->buffer.avail) want = conn->buffer.avail; if (want == 0) return; /* consume "want" bytes */ /* fwrite(&conn->buffer.mem[conn->buffer.base], 1, want, fp); */ conn->buffer.base += want; conn->buffer.avail -= want; /* reset buffer */ if (conn->buffer.avail == 0) { conn->buffer.base = 0; if (conn->paused) { fprintf(stderr, "tick: resuming stream\n"); conn->paused = 0; curl_easy_pause(conn->easy, CURLPAUSE_CONT); } } } /* Clean up the SockInfo structure */ static void remsock(SockInfo *f) { if(f) { event_del(&f->ev); free(f); } } /* Assign information to a SockInfo structure */ static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act, GlobalInfo *g) { int kind = (act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST; f->sockfd = s; f->action = act; f->easy = e; event_del(&f->ev); event_assign(&f->ev, g->evbase, f->sockfd, kind, event_cb, g); event_add(&f->ev, NULL); } /* Initialize a new SockInfo structure */ static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g) { SockInfo *fdp = calloc(sizeof(SockInfo), 1); fdp->global = g; setsock(fdp, s, easy, action, g); curl_multi_assign(g->multi, s, fdp); } /* CURLMOPT_SOCKETFUNCTION */ static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp) { GlobalInfo *g = (GlobalInfo*) cbp; SockInfo *fdp = (SockInfo*) sockp; const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" }; fprintf(MSG_OUT, "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]); if(what == CURL_POLL_REMOVE) { fprintf(MSG_OUT, "\n"); remsock(fdp); } else { if(!fdp) { fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]); addsock(s, e, what, g); } else { fprintf(MSG_OUT, "Changing action from %s to %s\n", whatstr[fdp->action], whatstr[what]); setsock(fdp, s, e, what, g); } } return 0; } /* CURLOPT_WRITEFUNCTION */ static size_t write_cb(void *ptr _Unused, size_t size, size_t nmemb, void *data) { size_t realsize = size * nmemb; ConnInfo *conn _Unused = (ConnInfo*) data; unsigned end = conn->buffer.base + conn->buffer.avail; if (realsize > (conn->buffer.size - end)) { fprintf(MSG_OUT, "write_cb: need %zd but have %u (pausing)\n", realsize, conn->buffer.size - end); conn->paused = 1; return CURL_WRITEFUNC_PAUSE; } /* add to end of buffer */ memcpy(&conn->buffer.mem[end], ptr, realsize); conn->buffer.avail += realsize; fprintf(MSG_OUT, "write_cb: buffer now %u bytes\n", conn->buffer.avail); return realsize; } /* CURLOPT_PROGRESSFUNCTION */ static int prog_cb(void *p, double dltotal, double dlnow, double ult _Unused, double uln _Unused) { ConnInfo *conn _Unused = (ConnInfo *)p; // fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal); return 0; } /* Create a new easy handle, and add it to the global curl_multi */ static void new_conn(char *url, GlobalInfo *g) { ConnInfo *conn; CURLMcode rc; struct timeval tv = (struct timeval) { 0, 100000 }; conn = calloc(1, sizeof(ConnInfo)); memset(conn, 0, sizeof(ConnInfo)); conn->error[0]='\0'; conn->easy = curl_easy_init(); if(!conn->easy) { fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n"); exit(2); } conn->global = g; conn->url = strdup(url); curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url); curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb); curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn); curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L); curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error); curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn); curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L); curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb); curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn); curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L); fprintf(MSG_OUT, "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url); rc = curl_multi_add_handle(g->multi, conn->easy); mcode_or_die("new_conn: curl_multi_add_handle", rc); /* note that the add_handle() will set a time-out to trigger very soon so that the necessary socket_action() call will be called by this app */ event_assign(&conn->periodic, g->evbase, -1, EV_TIMEOUT | EV_PERSIST, periodic_cb, conn); event_add(&conn->periodic, &tv); conn->buffer.mem = malloc(BUFFER_SIZE); conn->buffer.size = BUFFER_SIZE; // conn->buffer.base = conn->buffer.avail = 0; } int main(int argc, char **argv) { GlobalInfo g; int n; memset(&g, 0, sizeof(GlobalInfo)); g.evbase = event_base_new(); g.multi = curl_multi_init(); evtimer_assign(&g.timer_event, g.evbase, timer_cb, &g); /* setup the generic multi interface options we want */ curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb); curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g); curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb); curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g); for (n = 1; n < argc; ++n) new_conn(argv[n], &g); event_base_dispatch(g.evbase); /* this, of course, won't get called since only way to stop this program is via ctrl-C, but it is here to show how cleanup /would/ be done. */ event_del(&g.timer_event); event_base_free(g.evbase); curl_multi_cleanup(g.multi); return 0; }