url2file: new simple example

Just showing how to download the contents of a given URL into a local
file.

Based on a suggestion and example code by Georg Potthast

docs/examples/.gitignore

@@ -40,3 +40,4 @@ simplesmtp
 simplessl
 smtp-multi
 smtp-tls
+url2file

docs/examples/Makefile.inc

@@ -5,7 +5,7 @@ check_PROGRAMS = 10-at-a-time anyauthput cookie_interface debug fileupload \
   persistant post-callback postit2 sepheaders simple simplepost simplessl  \
   sendrecv httpcustomheader certinfo chkspeed ftpgetinfo ftp-wildcard \
   smtp-multi simplesmtp smtp-tls rtsp externalsocket resolve \
-  progressfunc pop3s pop3slist imap
+  progressfunc pop3s pop3slist imap url2file
 
 # These examples require external dependencies that may not be commonly
 # available on POSIX systems, so don't bother attempting to compile them here.

docs/examples/url2file.c

@@ -0,0 +1,81 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2012, 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.
+ *
+ ***************************************************************************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <curl/curl.h>
+
+static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
+{
+  size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
+  return written;
+}
+
+int main(int argc, char *argv[])
+{
+  CURL *curl_handle;
+  static const char *pagefilename = "page.out";
+  FILE *pagefile;
+
+  if(argc < 2 ) {
+    printf("Usage: %s <URL>\n", argv[0]);
+    return 1;
+  }
+
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  /* init the curl session */
+  curl_handle = curl_easy_init();
+
+  /* set URL to get here */
+  curl_easy_setopt(curl_handle, CURLOPT_URL, argv[1]);
+
+  /* Switch on full protocol/debug output while testing */
+  curl_easy_setopt(curl_handle, CURLOPT_VERBOSE, 1L);
+
+  /* disable progress meter, set to 0L to enable and disable debug output */
+  curl_easy_setopt(curl_handle, CURLOPT_NOPROGRESS, 1L);
+
+  /* send all data to this function  */
+  curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_data);
+
+  /* open the file */
+  pagefile = fopen(pagefilename, "wb");
+  if (pagefile) {
+
+    /* write the page body to this file handle. CURLOPT_FILE is also known as
+       CURLOPT_WRITEDATA*/
+    curl_easy_setopt(curl_handle, CURLOPT_FILE, pagefile);
+
+    /* get it! */
+    curl_easy_perform(curl_handle);
+
+    /* close the header file */
+    fclose(pagefile);
+  }
+
+  /* cleanup curl stuff */
+  curl_easy_cleanup(curl_handle);
+
+  return 0;
+}