1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
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
42 uv_loop_t *loop;
43 CURLM *curl_handle;
44 uv_timer_t timeout;
45
46 typedef struct curl_context_s {
47 uv_poll_t poll_handle;
48 curl_socket_t sockfd;
49 } curl_context_t;
50
create_curl_context(curl_socket_t sockfd)51 static 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
curl_close_cb(uv_handle_t * handle)65 static void curl_close_cb(uv_handle_t *handle)
66 {
67 curl_context_t *context = (curl_context_t *) handle->data;
68 free(context);
69 }
70
destroy_curl_context(curl_context_t * context)71 static void destroy_curl_context(curl_context_t *context)
72 {
73 uv_close((uv_handle_t *) &context->poll_handle, curl_close_cb);
74 }
75
add_download(const char * url,int num)76 static 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
check_multi_info(void)98 static 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
curl_perform(uv_poll_t * req,int status,int events)134 static 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
on_timeout(uv_timer_t * req)153 static 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
start_timeout(CURLM * multi,long timeout_ms,void * userp)161 static 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
handle_socket(CURL * easy,curl_socket_t s,int action,void * userp,void * socketp)175 static 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
main(int argc,char ** argv)211 int 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