1: /***************************************************************************
2: * _ _ ____ _
3: * Project ___| | | | _ \| |
4: * / __| | | | |_) | |
5: * | (__| |_| | _ <| |___
6: * \___|\___/|_| \_\_____|
7: *
8: * Copyright (C) 2012 - 2018, 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:
23: /* <DESC>
24: * demonstrate the use of multi socket interface with boost::asio
25: * </DESC>
26: */
27: /*
28: * This program is in c++ and uses boost::asio instead of libevent/libev.
29: * Requires boost::asio, boost::bind and boost::system
30: *
31: * This is an adaptation of libcurl's "hiperfifo.c" and "evhiperfifo.c"
32: * sample programs. This example implements a subset of the functionality from
33: * hiperfifo.c, for full functionality refer hiperfifo.c or evhiperfifo.c
34: *
35: * Written by Lijo Antony based on hiperfifo.c by Jeff Pohlmeyer
36: *
37: * When running, the program creates an easy handle for a URL and
38: * uses the curl_multi API to fetch it.
39: *
40: * Note:
41: * For the sake of simplicity, URL is hard coded to "www.google.com"
42: *
43: * This is purely a demo app, all retrieved data is simply discarded by the
44: * write callback.
45: *
46: * ===========================================================================
47: * WARNING: This example program is known to have flaws:
48: * https://github.com/curl/curl/issues/2407
49: *
50: * It still kept in the example repository with the hope that it might be
51: * useful, and maybe some day someone who knows enough about boost::asio will
52: * read this text, accept the challenge and make the example code work
53: * correctly. Until then: expect this example program to fail occasionally.
54: * ===========================================================================
55: */
56:
57:
58: #include <curl/curl.h>
59: #include <boost/asio.hpp>
60: #include <boost/bind.hpp>
61: #include <iostream>
62:
63: #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
64:
65: /* boost::asio related objects
66: * using global variables for simplicity
67: */
68: boost::asio::io_service io_service;
69: boost::asio::deadline_timer timer(io_service);
70: std::map<curl_socket_t, boost::asio::ip::tcp::socket *> socket_map;
71:
72: /* Global information, common to all connections */
73: typedef struct _GlobalInfo
74: {
75: CURLM *multi;
76: int still_running;
77: } GlobalInfo;
78:
79: /* Information associated with a specific easy handle */
80: typedef struct _ConnInfo
81: {
82: CURL *easy;
83: char *url;
84: GlobalInfo *global;
85: char error[CURL_ERROR_SIZE];
86: } ConnInfo;
87:
88: static void timer_cb(const boost::system::error_code & error, GlobalInfo *g);
89:
90: /* Update the event timer after curl_multi library calls */
91: static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
92: {
93: fprintf(MSG_OUT, "\nmulti_timer_cb: timeout_ms %ld", timeout_ms);
94:
95: /* cancel running timer */
96: timer.cancel();
97:
98: if(timeout_ms > 0) {
99: /* update timer */
100: timer.expires_from_now(boost::posix_time::millisec(timeout_ms));
101: timer.async_wait(boost::bind(&timer_cb, _1, g));
102: }
103: else if(timeout_ms == 0) {
104: /* call timeout function immediately */
105: boost::system::error_code error; /*success*/
106: timer_cb(error, g);
107: }
108:
109: return 0;
110: }
111:
112: /* Die if we get a bad CURLMcode somewhere */
113: static void mcode_or_die(const char *where, CURLMcode code)
114: {
115: if(CURLM_OK != code) {
116: const char *s;
117: switch(code) {
118: case CURLM_CALL_MULTI_PERFORM:
119: s = "CURLM_CALL_MULTI_PERFORM";
120: break;
121: case CURLM_BAD_HANDLE:
122: s = "CURLM_BAD_HANDLE";
123: break;
124: case CURLM_BAD_EASY_HANDLE:
125: s = "CURLM_BAD_EASY_HANDLE";
126: break;
127: case CURLM_OUT_OF_MEMORY:
128: s = "CURLM_OUT_OF_MEMORY";
129: break;
130: case CURLM_INTERNAL_ERROR:
131: s = "CURLM_INTERNAL_ERROR";
132: break;
133: case CURLM_UNKNOWN_OPTION:
134: s = "CURLM_UNKNOWN_OPTION";
135: break;
136: case CURLM_LAST:
137: s = "CURLM_LAST";
138: break;
139: default:
140: s = "CURLM_unknown";
141: break;
142: case CURLM_BAD_SOCKET:
143: s = "CURLM_BAD_SOCKET";
144: fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
145: /* ignore this error */
146: return;
147: }
148:
149: fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
150:
151: exit(code);
152: }
153: }
154:
155: /* Check for completed transfers, and remove their easy handles */
156: static void check_multi_info(GlobalInfo *g)
157: {
158: char *eff_url;
159: CURLMsg *msg;
160: int msgs_left;
161: ConnInfo *conn;
162: CURL *easy;
163: CURLcode res;
164:
165: fprintf(MSG_OUT, "\nREMAINING: %d", g->still_running);
166:
167: while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
168: if(msg->msg == CURLMSG_DONE) {
169: easy = msg->easy_handle;
170: res = msg->data.result;
171: curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
172: curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
173: fprintf(MSG_OUT, "\nDONE: %s => (%d) %s", eff_url, res, conn->error);
174: curl_multi_remove_handle(g->multi, easy);
175: free(conn->url);
176: curl_easy_cleanup(easy);
177: free(conn);
178: }
179: }
180: }
181:
182: /* Called by asio when there is an action on a socket */
183: static void event_cb(GlobalInfo *g, curl_socket_t s,
184: int action, const boost::system::error_code & error,
185: int *fdp)
186: {
187: fprintf(MSG_OUT, "\nevent_cb: action=%d", action);
188:
189: if(socket_map.find(s) == socket_map.end()) {
190: fprintf(MSG_OUT, "\nevent_cb: socket already closed");
191: return;
192: }
193:
194: /* make sure the event matches what are wanted */
195: if(*fdp == action || *fdp == CURL_POLL_INOUT) {
196: CURLMcode rc;
197: if(error)
198: action = CURL_CSELECT_ERR;
199: rc = curl_multi_socket_action(g->multi, s, action, &g->still_running);
200:
201: mcode_or_die("event_cb: curl_multi_socket_action", rc);
202: check_multi_info(g);
203:
204: if(g->still_running <= 0) {
205: fprintf(MSG_OUT, "\nlast transfer done, kill timeout");
206: timer.cancel();
207: }
208:
209: /* keep on watching.
210: * the socket may have been closed and/or fdp may have been changed
211: * in curl_multi_socket_action(), so check them both */
212: if(!error && socket_map.find(s) != socket_map.end() &&
213: (*fdp == action || *fdp == CURL_POLL_INOUT)) {
214: boost::asio::ip::tcp::socket *tcp_socket = socket_map.find(s)->second;
215:
216: if(action == CURL_POLL_IN) {
217: tcp_socket->async_read_some(boost::asio::null_buffers(),
218: boost::bind(&event_cb, g, s,
219: action, _1, fdp));
220: }
221: if(action == CURL_POLL_OUT) {
222: tcp_socket->async_write_some(boost::asio::null_buffers(),
223: boost::bind(&event_cb, g, s,
224: action, _1, fdp));
225: }
226: }
227: }
228: }
229:
230: /* Called by asio when our timeout expires */
231: static void timer_cb(const boost::system::error_code & error, GlobalInfo *g)
232: {
233: if(!error) {
234: fprintf(MSG_OUT, "\ntimer_cb: ");
235:
236: CURLMcode rc;
237: rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0,
238: &g->still_running);
239:
240: mcode_or_die("timer_cb: curl_multi_socket_action", rc);
241: check_multi_info(g);
242: }
243: }
244:
245: /* Clean up any data */
246: static void remsock(int *f, GlobalInfo *g)
247: {
248: fprintf(MSG_OUT, "\nremsock: ");
249:
250: if(f) {
251: free(f);
252: }
253: }
254:
255: static void setsock(int *fdp, curl_socket_t s, CURL *e, int act, int oldact,
256: GlobalInfo *g)
257: {
258: fprintf(MSG_OUT, "\nsetsock: socket=%d, act=%d, fdp=%p", s, act, fdp);
259:
260: std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
261: socket_map.find(s);
262:
263: if(it == socket_map.end()) {
264: fprintf(MSG_OUT, "\nsocket %d is a c-ares socket, ignoring", s);
265: return;
266: }
267:
268: boost::asio::ip::tcp::socket * tcp_socket = it->second;
269:
270: *fdp = act;
271:
272: if(act == CURL_POLL_IN) {
273: fprintf(MSG_OUT, "\nwatching for socket to become readable");
274: if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
275: tcp_socket->async_read_some(boost::asio::null_buffers(),
276: boost::bind(&event_cb, g, s,
277: CURL_POLL_IN, _1, fdp));
278: }
279: }
280: else if(act == CURL_POLL_OUT) {
281: fprintf(MSG_OUT, "\nwatching for socket to become writable");
282: if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
283: tcp_socket->async_write_some(boost::asio::null_buffers(),
284: boost::bind(&event_cb, g, s,
285: CURL_POLL_OUT, _1, fdp));
286: }
287: }
288: else if(act == CURL_POLL_INOUT) {
289: fprintf(MSG_OUT, "\nwatching for socket to become readable & writable");
290: if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
291: tcp_socket->async_read_some(boost::asio::null_buffers(),
292: boost::bind(&event_cb, g, s,
293: CURL_POLL_IN, _1, fdp));
294: }
295: if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
296: tcp_socket->async_write_some(boost::asio::null_buffers(),
297: boost::bind(&event_cb, g, s,
298: CURL_POLL_OUT, _1, fdp));
299: }
300: }
301: }
302:
303: static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
304: {
305: /* fdp is used to store current action */
306: int *fdp = (int *) calloc(sizeof(int), 1);
307:
308: setsock(fdp, s, easy, action, 0, g);
309: curl_multi_assign(g->multi, s, fdp);
310: }
311:
312: /* CURLMOPT_SOCKETFUNCTION */
313: static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
314: {
315: fprintf(MSG_OUT, "\nsock_cb: socket=%d, what=%d, sockp=%p", s, what, sockp);
316:
317: GlobalInfo *g = (GlobalInfo*) cbp;
318: int *actionp = (int *) sockp;
319: const char *whatstr[] = { "none", "IN", "OUT", "INOUT", "REMOVE"};
320:
321: fprintf(MSG_OUT,
322: "\nsocket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
323:
324: if(what == CURL_POLL_REMOVE) {
325: fprintf(MSG_OUT, "\n");
326: remsock(actionp, g);
327: }
328: else {
329: if(!actionp) {
330: fprintf(MSG_OUT, "\nAdding data: %s", whatstr[what]);
331: addsock(s, e, what, g);
332: }
333: else {
334: fprintf(MSG_OUT,
335: "\nChanging action from %s to %s",
336: whatstr[*actionp], whatstr[what]);
337: setsock(actionp, s, e, what, *actionp, g);
338: }
339: }
340:
341: return 0;
342: }
343:
344: /* CURLOPT_WRITEFUNCTION */
345: static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
346: {
347: size_t written = size * nmemb;
348: char *pBuffer = (char *)malloc(written + 1);
349:
350: strncpy(pBuffer, (const char *)ptr, written);
351: pBuffer[written] = '\0';
352:
353: fprintf(MSG_OUT, "%s", pBuffer);
354:
355: free(pBuffer);
356:
357: return written;
358: }
359:
360: /* CURLOPT_PROGRESSFUNCTION */
361: static int prog_cb(void *p, double dltotal, double dlnow, double ult,
362: double uln)
363: {
364: ConnInfo *conn = (ConnInfo *)p;
365:
366: (void)ult;
367: (void)uln;
368:
369: fprintf(MSG_OUT, "\nProgress: %s (%g/%g)", conn->url, dlnow, dltotal);
370: fprintf(MSG_OUT, "\nProgress: %s (%g)", conn->url, ult);
371:
372: return 0;
373: }
374:
375: /* CURLOPT_OPENSOCKETFUNCTION */
376: static curl_socket_t opensocket(void *clientp, curlsocktype purpose,
377: struct curl_sockaddr *address)
378: {
379: fprintf(MSG_OUT, "\nopensocket :");
380:
381: curl_socket_t sockfd = CURL_SOCKET_BAD;
382:
383: /* restrict to IPv4 */
384: if(purpose == CURLSOCKTYPE_IPCXN && address->family == AF_INET) {
385: /* create a tcp socket object */
386: boost::asio::ip::tcp::socket *tcp_socket =
387: new boost::asio::ip::tcp::socket(io_service);
388:
389: /* open it and get the native handle*/
390: boost::system::error_code ec;
391: tcp_socket->open(boost::asio::ip::tcp::v4(), ec);
392:
393: if(ec) {
394: /* An error occurred */
395: std::cout << std::endl << "Couldn't open socket [" << ec << "][" <<
396: ec.message() << "]";
397: fprintf(MSG_OUT, "\nERROR: Returning CURL_SOCKET_BAD to signal error");
398: }
399: else {
400: sockfd = tcp_socket->native_handle();
401: fprintf(MSG_OUT, "\nOpened socket %d", sockfd);
402:
403: /* save it for monitoring */
404: socket_map.insert(std::pair<curl_socket_t,
405: boost::asio::ip::tcp::socket *>(sockfd, tcp_socket));
406: }
407: }
408:
409: return sockfd;
410: }
411:
412: /* CURLOPT_CLOSESOCKETFUNCTION */
413: static int close_socket(void *clientp, curl_socket_t item)
414: {
415: fprintf(MSG_OUT, "\nclose_socket : %d", item);
416:
417: std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
418: socket_map.find(item);
419:
420: if(it != socket_map.end()) {
421: delete it->second;
422: socket_map.erase(it);
423: }
424:
425: return 0;
426: }
427:
428: /* Create a new easy handle, and add it to the global curl_multi */
429: static void new_conn(char *url, GlobalInfo *g)
430: {
431: ConnInfo *conn;
432: CURLMcode rc;
433:
434: conn = (ConnInfo *) calloc(1, sizeof(ConnInfo));
435:
436: conn->easy = curl_easy_init();
437: if(!conn->easy) {
438: fprintf(MSG_OUT, "\ncurl_easy_init() failed, exiting!");
439: exit(2);
440: }
441:
442: conn->global = g;
443: conn->url = strdup(url);
444: curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
445: curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
446: curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
447: curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
448: curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
449: curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
450: curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 1L);
451: curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
452: curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
453: curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
454: curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
455:
456: /* call this function to get a socket */
457: curl_easy_setopt(conn->easy, CURLOPT_OPENSOCKETFUNCTION, opensocket);
458:
459: /* call this function to close a socket */
460: curl_easy_setopt(conn->easy, CURLOPT_CLOSESOCKETFUNCTION, close_socket);
461:
462: fprintf(MSG_OUT,
463: "\nAdding easy %p to multi %p (%s)", conn->easy, g->multi, url);
464: rc = curl_multi_add_handle(g->multi, conn->easy);
465: mcode_or_die("new_conn: curl_multi_add_handle", rc);
466:
467: /* note that the add_handle() will set a time-out to trigger very soon so
468: that the necessary socket_action() call will be called by this app */
469: }
470:
471: int main(int argc, char **argv)
472: {
473: GlobalInfo g;
474:
475: (void)argc;
476: (void)argv;
477:
478: memset(&g, 0, sizeof(GlobalInfo));
479: g.multi = curl_multi_init();
480:
481: curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
482: curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
483: curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
484: curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
485:
486: new_conn((char *)"www.google.com", &g); /* add a URL */
487:
488: /* enter io_service run loop */
489: io_service.run();
490:
491: curl_multi_cleanup(g.multi);
492:
493: fprintf(MSG_OUT, "\ndone.\n");
494:
495: return 0;
496: }
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