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getinmemory.c

Download getinmemory.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2011, 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 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 <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;
 
  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;
}

You'll also find all examples in the distribution archive, in the docs/examples directory.