curl / libcurl / API / Examples / url2file.c

url2file.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 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.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.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/
/* <DESC>
 * Download a given URL into a local file named page.out.
 * </DESC>
 */
#ifdef _MSC_VER
#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS  /* for fopen() */
#endif
#endif
 
#include <stdio.h>
#include <stdlib.h>
 
#include <curl/curl.h>
 
static size_t write_cb(char *ptr, size_t size, size_t nmemb, void *stream)
{
  size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
  return written;
}
 
int main(int argc, const char *argv[])
{
  static const char *pagefilename = "page.out";
 
  CURLcode result;
  CURL *curl;
 
  if(argc < 2) {
    printf("Usage: %s <URL>\n", argv[0]);
    return 1;
  }
 
  result = curl_global_init(CURL_GLOBAL_ALL);
  if(result != CURLE_OK) {
    fprintf(stderr, "Could not init curl\n");
    return (int)result;
  }
 
  /* init the curl session */
  curl = curl_easy_init();
  if(curl) {
    FILE *pagefile;
 
    /* set URL to get here */
    curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
 
    /* Switch on full protocol/debug output while testing */
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
 
    /* disable progress meter, set to 0L to enable it */
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
 
    /* send all data to this function */
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_cb);
 
    /* open the file */
    pagefile = fopen(pagefilename, "wb");
    if(pagefile) {
 
      /* write the page body to this file handle */
      curl_easy_setopt(curl, CURLOPT_WRITEDATA, pagefile);
 
      /* get it! */
      result = curl_easy_perform(curl);
 
      /* close the header file */
      fclose(pagefile);
    }
 
    /* cleanup curl stuff */
    curl_easy_cleanup(curl);
  }
 
  curl_global_cleanup();
 
  return (int)result;
}

Notice

This source code example is simplified and may ignore return codes and error checks. We do this to highlight the libcurl function calls and related options and reduce unrelated code.

A real-world application does of course properly check every return value and exit correctly at the first serious error.