/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2011, Daniel Stenberg, , 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 http://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. * ***************************************************************************/ /* Example source code to show how the callback function can be used to * download data into a chunk of memory instead of storing it in a file. */ #include #include #include #include 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; mem->memory = realloc(mem->memory, mem->size + realsize + 1); if (mem->memory == NULL) { /* out of memory! */ printf("not enough memory (realloc returned NULL)\n"); exit(EXIT_FAILURE); } memcpy(&(mem->memory[mem->size]), contents, realsize); mem->size += realsize; mem->memory[mem->size] = 0; return realsize; } int main(void) { CURL *curl_handle; struct MemoryStruct chunk; chunk.memory = malloc(1); /* will be grown as needed by the realloc above */ chunk.size = 0; /* no data at this point */ curl_global_init(CURL_GLOBAL_ALL); /* init the curl session */ curl_handle = curl_easy_init(); /* specify URL to get */ curl_easy_setopt(curl_handle, CURLOPT_URL, "http://www.example.com/"); /* send all data to this function */ curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback); /* we pass our 'chunk' struct to the callback function */ curl_easy_setopt(curl_handle, 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_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0"); /* get it! */ curl_easy_perform(curl_handle); /* cleanup curl stuff */ curl_easy_cleanup(curl_handle); /* * 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! * * You should be aware of the fact that at this point we might have an * allocated data block, and nothing has yet deallocated that data. So when * you're done with it, you should free() it as a nice application. */ printf("%lu bytes retrieved\n", (long)chunk.size); if(chunk.memory) free(chunk.memory); /* we're done with libcurl, so clean it up */ curl_global_cleanup(); return 0; }