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 * Make an HTTP POST with data from memory and receive response in memory.
26 * </DESC>
27 */
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <curl/curl.h>
32
33 struct MemoryStruct {
34 char *memory;
35 size_t size;
36 };
37
38 static size_t
WriteMemoryCallback(void * contents,size_t size,size_t nmemb,void * userp)39 WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
40 {
41 size_t realsize = size * nmemb;
42 struct MemoryStruct *mem = (struct MemoryStruct *)userp;
43
44 char *ptr = realloc(mem->memory, mem->size + realsize + 1);
45 if(!ptr) {
46 /* out of memory! */
47 printf("not enough memory (realloc returned NULL)\n");
48 return 0;
49 }
50
51 mem->memory = ptr;
52 memcpy(&(mem->memory[mem->size]), contents, realsize);
53 mem->size += realsize;
54 mem->memory[mem->size] = 0;
55
56 return realsize;
57 }
58
main(void)59 int main(void)
60 {
61 CURL *curl;
62 CURLcode res;
63 struct MemoryStruct chunk;
64 static const char *postthis = "Field=1&Field=2&Field=3";
65
66 chunk.memory = malloc(1); /* grown as needed by realloc above */
67 chunk.size = 0; /* no data at this point */
68
69 curl_global_init(CURL_GLOBAL_ALL);
70 curl = curl_easy_init();
71 if(curl) {
72 curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.org/");
73
74 /* send all data to this function */
75 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
76
77 /* we pass our 'chunk' struct to the callback function */
78 curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
79
80 /* some servers do not like requests that are made without a user-agent
81 field, so we provide one */
82 curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
83
84 curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis);
85
86 /* if we do not provide POSTFIELDSIZE, libcurl calls strlen() by itself */
87 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis));
88
89 /* Perform the request, res gets the return code */
90 res = curl_easy_perform(curl);
91 /* Check for errors */
92 if(res != CURLE_OK) {
93 fprintf(stderr, "curl_easy_perform() failed: %s\n",
94 curl_easy_strerror(res));
95 }
96 else {
97 /*
98 * Now, our chunk.memory points to a memory block that is chunk.size
99 * bytes big and contains the remote file.
100 *
101 * Do something nice with it!
102 */
103 printf("%s\n",chunk.memory);
104 }
105
106 /* always cleanup */
107 curl_easy_cleanup(curl);
108 }
109
110 free(chunk.memory);
111 curl_global_cleanup();
112 return 0;
113 }
114
