1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2017, 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 /* <DESC>
23 * An example of curl_easy_send() and curl_easy_recv() usage.
24 * </DESC>
25 */
26
27 #include <stdio.h>
28 #include <string.h>
29 #include <curl/curl.h>
30
31 /* Auxiliary function that waits on the socket. */
wait_on_socket(curl_socket_t sockfd,int for_recv,long timeout_ms)32 static int wait_on_socket(curl_socket_t sockfd, int for_recv, long timeout_ms)
33 {
34 struct timeval tv;
35 fd_set infd, outfd, errfd;
36 int res;
37
38 tv.tv_sec = timeout_ms / 1000;
39 tv.tv_usec = (timeout_ms % 1000) * 1000;
40
41 FD_ZERO(&infd);
42 FD_ZERO(&outfd);
43 FD_ZERO(&errfd);
44
45 FD_SET(sockfd, &errfd); /* always check for error */
46
47 if(for_recv) {
48 FD_SET(sockfd, &infd);
49 }
50 else {
51 FD_SET(sockfd, &outfd);
52 }
53
54 /* select() returns the number of signalled sockets or -1 */
55 res = select((int)sockfd + 1, &infd, &outfd, &errfd, &tv);
56 return res;
57 }
58
main(void)59 int main(void)
60 {
61 CURL *curl;
62 CURLcode res;
63 /* Minimalistic http request */
64 const char *request = "GET / HTTP/1.0\r\nHost: example.com\r\n\r\n";
65 size_t request_len = strlen(request);
66 curl_socket_t sockfd;
67 size_t nsent_total = 0;
68
69 /* A general note of caution here: if you're using curl_easy_recv() or
70 curl_easy_send() to implement HTTP or _any_ other protocol libcurl
71 supports "natively", you're doing it wrong and you should stop.
72
73 This example uses HTTP only to show how to use this API, it does not
74 suggest that writing an application doing this is sensible.
75 */
76
77 curl = curl_easy_init();
78 if(curl) {
79 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
80 /* Do not do the transfer - only connect to host */
81 curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
82 res = curl_easy_perform(curl);
83
84 if(res != CURLE_OK) {
85 printf("Error: %s\n", curl_easy_strerror(res));
86 return 1;
87 }
88
89 /* Extract the socket from the curl handle - we'll need it for waiting. */
90 res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
91
92 if(res != CURLE_OK) {
93 printf("Error: %s\n", curl_easy_strerror(res));
94 return 1;
95 }
96
97 printf("Sending request.\n");
98
99 do {
100 /* Warning: This example program may loop indefinitely.
101 * A production-quality program must define a timeout and exit this loop
102 * as soon as the timeout has expired. */
103 size_t nsent;
104 do {
105 nsent = 0;
106 res = curl_easy_send(curl, request + nsent_total,
107 request_len - nsent_total, &nsent);
108 nsent_total += nsent;
109
110 if(res == CURLE_AGAIN && !wait_on_socket(sockfd, 0, 60000L)) {
111 printf("Error: timeout.\n");
112 return 1;
113 }
114 } while(res == CURLE_AGAIN);
115
116 if(res != CURLE_OK) {
117 printf("Error: %s\n", curl_easy_strerror(res));
118 return 1;
119 }
120
121 printf("Sent %" CURL_FORMAT_CURL_OFF_T " bytes.\n",
122 (curl_off_t)nsent);
123
124 } while(nsent_total < request_len);
125
126 printf("Reading response.\n");
127
128 for(;;) {
129 /* Warning: This example program may loop indefinitely (see above). */
130 char buf[1024];
131 size_t nread;
132 do {
133 nread = 0;
134 res = curl_easy_recv(curl, buf, sizeof(buf), &nread);
135
136 if(res == CURLE_AGAIN && !wait_on_socket(sockfd, 1, 60000L)) {
137 printf("Error: timeout.\n");
138 return 1;
139 }
140 } while(res == CURLE_AGAIN);
141
142 if(res != CURLE_OK) {
143 printf("Error: %s\n", curl_easy_strerror(res));
144 break;
145 }
146
147 if(nread == 0) {
148 /* end of the response */
149 break;
150 }
151
152 printf("Received %" CURL_FORMAT_CURL_OFF_T " bytes.\n",
153 (curl_off_t)nread);
154 }
155
156 /* always cleanup */
157 curl_easy_cleanup(curl);
158 }
159 return 0;
160 }
161