xref: /third_party/curl/docs/examples/debug.c (revision 13498266)
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/* <DESC>
25 * Show how CURLOPT_DEBUGFUNCTION can be used.
26 * </DESC>
27 */
28#include <stdio.h>
29#include <curl/curl.h>
30
31struct data {
32  char trace_ascii; /* 1 or 0 */
33};
34
35static
36void dump(const char *text,
37          FILE *stream, unsigned char *ptr, size_t size,
38          char nohex)
39{
40  size_t i;
41  size_t c;
42
43  unsigned int width = 0x10;
44
45  if(nohex)
46    /* without the hex output, we can fit more on screen */
47    width = 0x40;
48
49  fprintf(stream, "%s, %10.10lu bytes (0x%8.8lx)\n",
50          text, (unsigned long)size, (unsigned long)size);
51
52  for(i = 0; i<size; i += width) {
53
54    fprintf(stream, "%4.4lx: ", (unsigned long)i);
55
56    if(!nohex) {
57      /* hex not disabled, show it */
58      for(c = 0; c < width; c++)
59        if(i + c < size)
60          fprintf(stream, "%02x ", ptr[i + c]);
61        else
62          fputs("   ", stream);
63    }
64
65    for(c = 0; (c < width) && (i + c < size); c++) {
66      /* check for 0D0A; if found, skip past and start a new line of output */
67      if(nohex && (i + c + 1 < size) && ptr[i + c] == 0x0D &&
68         ptr[i + c + 1] == 0x0A) {
69        i += (c + 2 - width);
70        break;
71      }
72      fprintf(stream, "%c",
73              (ptr[i + c] >= 0x20) && (ptr[i + c]<0x80)?ptr[i + c]:'.');
74      /* check again for 0D0A, to avoid an extra \n if it's at width */
75      if(nohex && (i + c + 2 < size) && ptr[i + c + 1] == 0x0D &&
76         ptr[i + c + 2] == 0x0A) {
77        i += (c + 3 - width);
78        break;
79      }
80    }
81    fputc('\n', stream); /* newline */
82  }
83  fflush(stream);
84}
85
86static
87int my_trace(CURL *handle, curl_infotype type,
88             char *data, size_t size,
89             void *userp)
90{
91  struct data *config = (struct data *)userp;
92  const char *text;
93  (void)handle; /* prevent compiler warning */
94
95  switch(type) {
96  case CURLINFO_TEXT:
97    fprintf(stderr, "== Info: %s", data);
98    return 0;
99  case CURLINFO_HEADER_OUT:
100    text = "=> Send header";
101    break;
102  case CURLINFO_DATA_OUT:
103    text = "=> Send data";
104    break;
105  case CURLINFO_SSL_DATA_OUT:
106    text = "=> Send SSL data";
107    break;
108  case CURLINFO_HEADER_IN:
109    text = "<= Recv header";
110    break;
111  case CURLINFO_DATA_IN:
112    text = "<= Recv data";
113    break;
114  case CURLINFO_SSL_DATA_IN:
115    text = "<= Recv SSL data";
116    break;
117  default: /* in case a new one is introduced to shock us */
118    return 0;
119  }
120
121  dump(text, stderr, (unsigned char *)data, size, config->trace_ascii);
122  return 0;
123}
124
125int main(void)
126{
127  CURL *curl;
128  CURLcode res;
129  struct data config;
130
131  config.trace_ascii = 1; /* enable ascii tracing */
132
133  curl = curl_easy_init();
134  if(curl) {
135    curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, my_trace);
136    curl_easy_setopt(curl, CURLOPT_DEBUGDATA, &config);
137
138    /* the DEBUGFUNCTION has no effect until we enable VERBOSE */
139    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
140
141    /* example.com is redirected, so we tell libcurl to follow redirection */
142    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
143
144    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
145    res = curl_easy_perform(curl);
146    /* Check for errors */
147    if(res != CURLE_OK)
148      fprintf(stderr, "curl_easy_perform() failed: %s\n",
149              curl_easy_strerror(res));
150
151    /* always cleanup */
152    curl_easy_cleanup(curl);
153  }
154  return 0;
155}
156