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. */
32static 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
59int 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