xref: /third_party/curl/docs/examples/multi-uv.c (revision 13498266) 
1/***************************************************************************
2 *                                  _   _ ____  _
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4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25/* <DESC>
26 * multi_socket API using libuv
27 * </DESC>
28 */
29/* Example application using the multi socket interface to download multiple
30   files in parallel, powered by libuv.
31
32   Requires libuv and (of course) libcurl.
33
34   See https://nikhilm.github.io/uvbook/ for more information on libuv.
35*/
36
37#include <stdio.h>
38#include <stdlib.h>
39#include <uv.h>
40#include <curl/curl.h>
41
42uv_loop_t *loop;
43CURLM *curl_handle;
44uv_timer_t timeout;
45
46typedef struct curl_context_s {
47  uv_poll_t poll_handle;
48  curl_socket_t sockfd;
49} curl_context_t;
50
51static curl_context_t *create_curl_context(curl_socket_t sockfd)
52{
53  curl_context_t *context;
54
55  context = (curl_context_t *) malloc(sizeof(*context));
56
57  context->sockfd = sockfd;
58
59  uv_poll_init_socket(loop, &context->poll_handle, sockfd);
60  context->poll_handle.data = context;
61
62  return context;
63}
64
65static void curl_close_cb(uv_handle_t *handle)
66{
67  curl_context_t *context = (curl_context_t *) handle->data;
68  free(context);
69}
70
71static void destroy_curl_context(curl_context_t *context)
72{
73  uv_close((uv_handle_t *) &context->poll_handle, curl_close_cb);
74}
75
76static void add_download(const char *url, int num)
77{
78  char filename[50];
79  FILE *file;
80  CURL *handle;
81
82  snprintf(filename, 50, "%d.download", num);
83
84  file = fopen(filename, "wb");
85  if(!file) {
86    fprintf(stderr, "Error opening %s\n", filename);
87    return;
88  }
89
90  handle = curl_easy_init();
91  curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
92  curl_easy_setopt(handle, CURLOPT_PRIVATE, file);
93  curl_easy_setopt(handle, CURLOPT_URL, url);
94  curl_multi_add_handle(curl_handle, handle);
95  fprintf(stderr, "Added download %s -> %s\n", url, filename);
96}
97
98static void check_multi_info(void)
99{
100  char *done_url;
101  CURLMsg *message;
102  int pending;
103  CURL *easy_handle;
104  FILE *file;
105
106  while((message = curl_multi_info_read(curl_handle, &pending))) {
107    switch(message->msg) {
108    case CURLMSG_DONE:
109      /* Do not use message data after calling curl_multi_remove_handle() and
110         curl_easy_cleanup(). As per curl_multi_info_read() docs:
111         "WARNING: The data the returned pointer points to will not survive
112         calling curl_multi_cleanup, curl_multi_remove_handle or
113         curl_easy_cleanup." */
114      easy_handle = message->easy_handle;
115
116      curl_easy_getinfo(easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
117      curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file);
118      printf("%s DONE\n", done_url);
119
120      curl_multi_remove_handle(curl_handle, easy_handle);
121      curl_easy_cleanup(easy_handle);
122      if(file) {
123        fclose(file);
124      }
125      break;
126
127    default:
128      fprintf(stderr, "CURLMSG default\n");
129      break;
130    }
131  }
132}
133
134static void curl_perform(uv_poll_t *req, int status, int events)
135{
136  int running_handles;
137  int flags = 0;
138  curl_context_t *context;
139
140  if(events & UV_READABLE)
141    flags |= CURL_CSELECT_IN;
142  if(events & UV_WRITABLE)
143    flags |= CURL_CSELECT_OUT;
144
145  context = (curl_context_t *) req->data;
146
147  curl_multi_socket_action(curl_handle, context->sockfd, flags,
148                           &running_handles);
149
150  check_multi_info();
151}
152
153static void on_timeout(uv_timer_t *req)
154{
155  int running_handles;
156  curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0,
157                           &running_handles);
158  check_multi_info();
159}
160
161static int start_timeout(CURLM *multi, long timeout_ms, void *userp)
162{
163  if(timeout_ms < 0) {
164    uv_timer_stop(&timeout);
165  }
166  else {
167    if(timeout_ms == 0)
168      timeout_ms = 1; /* 0 means directly call socket_action, but we will do it
169                         in a bit */
170    uv_timer_start(&timeout, on_timeout, timeout_ms, 0);
171  }
172  return 0;
173}
174
175static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp,
176                  void *socketp)
177{
178  curl_context_t *curl_context;
179  int events = 0;
180
181  switch(action) {
182  case CURL_POLL_IN:
183  case CURL_POLL_OUT:
184  case CURL_POLL_INOUT:
185    curl_context = socketp ?
186      (curl_context_t *) socketp : create_curl_context(s);
187
188    curl_multi_assign(curl_handle, s, (void *) curl_context);
189
190    if(action != CURL_POLL_IN)
191      events |= UV_WRITABLE;
192    if(action != CURL_POLL_OUT)
193      events |= UV_READABLE;
194
195    uv_poll_start(&curl_context->poll_handle, events, curl_perform);
196    break;
197  case CURL_POLL_REMOVE:
198    if(socketp) {
199      uv_poll_stop(&((curl_context_t*)socketp)->poll_handle);
200      destroy_curl_context((curl_context_t*) socketp);
201      curl_multi_assign(curl_handle, s, NULL);
202    }
203    break;
204  default:
205    abort();
206  }
207
208  return 0;
209}
210
211int main(int argc, char **argv)
212{
213  loop = uv_default_loop();
214
215  if(argc <= 1)
216    return 0;
217
218  if(curl_global_init(CURL_GLOBAL_ALL)) {
219    fprintf(stderr, "Could not init curl\n");
220    return 1;
221  }
222
223  uv_timer_init(loop, &timeout);
224
225  curl_handle = curl_multi_init();
226  curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
227  curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
228
229  while(argc-- > 1) {
230    add_download(argv[argc], argc);
231  }
232
233  uv_run(loop, UV_RUN_DEFAULT);
234  curl_multi_cleanup(curl_handle);
235
236  return 0;
237}
238