| /***************************************************************************** |
| * _ _ ____ _ |
| * Project ___| | | | _ \| | |
| * / __| | | | |_) | | |
| * | (__| |_| | _ <| |___ |
| * \___|\___/|_| \_\_____| |
| * |
| * |
| * 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 <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include <curl/curl.h> |
| |
| struct MemoryStruct { |
| char *memory; |
| size_t size; |
| }; |
| |
| |
| static size_t |
| WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data) |
| { |
| size_t realsize = size * nmemb; |
| struct MemoryStruct *mem = (struct MemoryStruct *)data; |
| |
| 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]), ptr, realsize); |
| mem->size += realsize; |
| mem->memory[mem->size] = 0; |
| |
| return realsize; |
| } |
| |
| |
| int main(int argc, char **argv) |
| { |
| 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", chunk.size); |
| |
| if(chunk.memory) |
| free(chunk.memory); |
| |
| /* we're done with libcurl, so clean it up */ |
| curl_global_cleanup(); |
| |
| return 0; |
| } |