1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel (at) 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 source code that issues a HTTP POST and we provide the actual 24 * data through a read callback. 25 * </DESC> 26 */ 27 #include <stdio.h> 28 #include <string.h> 29 #include <curl/curl.h> 30 31 const char data[]="this is what we post to the silly web server"; 32 33 struct WriteThis { 34 const char *readptr; 35 long sizeleft; 36 }; 37 38 static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp) 39 { 40 struct WriteThis *pooh = (struct WriteThis *)userp; 41 42 if(size*nmemb < 1) 43 return 0; 44 45 if(pooh->sizeleft) { 46 *(char *)ptr = pooh->readptr[0]; /* copy one single byte */ 47 pooh->readptr++; /* advance pointer */ 48 pooh->sizeleft--; /* less data left */ 49 return 1; /* we return 1 byte at a time! */ 50 } 51 52 return 0; /* no more data left to deliver */ 53 } 54 55 int main(void) 56 { 57 CURL *curl; 58 CURLcode res; 59 60 struct WriteThis pooh; 61 62 pooh.readptr = data; 63 pooh.sizeleft = (long)strlen(data); 64 65 /* In windows, this will init the winsock stuff */ 66 res = curl_global_init(CURL_GLOBAL_DEFAULT); 67 /* Check for errors */ 68 if(res != CURLE_OK) { 69 fprintf(stderr, "curl_global_init() failed: %s\n", 70 curl_easy_strerror(res)); 71 return 1; 72 } 73 74 /* get a curl handle */ 75 curl = curl_easy_init(); 76 if(curl) { 77 /* First set the URL that is about to receive our POST. */ 78 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/index.cgi"); 79 80 /* Now specify we want to POST data */ 81 curl_easy_setopt(curl, CURLOPT_POST, 1L); 82 83 /* we want to use our own read function */ 84 curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback); 85 86 /* pointer to pass to our read function */ 87 curl_easy_setopt(curl, CURLOPT_READDATA, &pooh); 88 89 /* get verbose debug output please */ 90 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L); 91 92 /* 93 If you use POST to a HTTP 1.1 server, you can send data without knowing 94 the size before starting the POST if you use chunked encoding. You 95 enable this by adding a header like "Transfer-Encoding: chunked" with 96 CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must 97 specify the size in the request. 98 */ 99 #ifdef USE_CHUNKED 100 { 101 struct curl_slist *chunk = NULL; 102 103 chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked"); 104 res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk); 105 /* use curl_slist_free_all() after the *perform() call to free this 106 list again */ 107 } 108 #else 109 /* Set the expected POST size. If you want to POST large amounts of data, 110 consider CURLOPT_POSTFIELDSIZE_LARGE */ 111 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, pooh.sizeleft); 112 #endif 113 114 #ifdef DISABLE_EXPECT 115 /* 116 Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" 117 header. You can disable this header with CURLOPT_HTTPHEADER as usual. 118 NOTE: if you want chunked transfer too, you need to combine these two 119 since you can only set one list of headers with CURLOPT_HTTPHEADER. */ 120 121 /* A less good option would be to enforce HTTP 1.0, but that might also 122 have other implications. */ 123 { 124 struct curl_slist *chunk = NULL; 125 126 chunk = curl_slist_append(chunk, "Expect:"); 127 res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk); 128 /* use curl_slist_free_all() after the *perform() call to free this 129 list again */ 130 } 131 #endif 132 133 /* Perform the request, res will get the return code */ 134 res = curl_easy_perform(curl); 135 /* Check for errors */ 136 if(res != CURLE_OK) 137 fprintf(stderr, "curl_easy_perform() failed: %s\n", 138 curl_easy_strerror(res)); 139 140 /* always cleanup */ 141 curl_easy_cleanup(curl); 142 } 143 curl_global_cleanup(); 144 return 0; 145 } 146
