/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ /* <DESC> * Make a HTTP POST with data from memory and receive response in memory. * </DESC> */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <curl/curl.h> struct MemoryStruct { char *memory; size_t size; }; static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) { size_t realsize = size * nmemb; struct MemoryStruct *mem = (struct MemoryStruct *)userp; char *ptr = realloc(mem->memory, mem->size + realsize + 1); if(!ptr) { /* out of memory! */ printf("not enough memory (realloc returned NULL)\n"); return 0; } mem->memory = ptr; memcpy(&(mem->memory[mem->size]), contents, realsize); mem->size += realsize; mem->memory[mem->size] = 0; return realsize; } int main(void) { CURL *curl; CURLcode res; struct MemoryStruct chunk; static const char *postthis = "Field=1&Field=2&Field=3"; chunk.memory = malloc(1); /* will be grown as needed by realloc above */ chunk.size = 0; /* no data at this point */ curl_global_init(CURL_GLOBAL_ALL); curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.org/"); /* send all data to this function */ curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback); /* we pass our 'chunk' struct to the callback function */ curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk); /* some servers don't like requests that are made without a user-agent field, so we provide one */ curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0"); curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis); /* if we don't provide POSTFIELDSIZE, libcurl will strlen() by itself */ curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis)); /* Perform the request, res will get the return code */ res = curl_easy_perform(curl); /* Check for errors */ if(res != CURLE_OK) { fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res)); } else { /* * Now, our chunk.memory points to a memory block that is chunk.size * bytes big and contains the remote file. * * Do something nice with it! */ printf("%s\n",chunk.memory); } /* always cleanup */ curl_easy_cleanup(curl); free(chunk.memory); /* we're done with libcurl, so clean it up */ curl_global_cleanup(); } return 0; }