xref: /curl/docs/examples/debug.c (revision fbf5d507)
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 
31 struct data {
32   char trace_ascii; /* 1 or 0 */
33 };
34 
35 static
dump(const char * text,FILE * stream,unsigned char * ptr,size_t size,char nohex)36 void 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 
86 static
my_trace(CURL * handle,curl_infotype type,char * data,size_t size,void * userp)87 int 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 
main(void)125 int 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