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Annotation of embedaddon/curl/docs/examples/getinmemory.c, revision 1.1.1.1

1.1       misho       1: /***************************************************************************
                      2:  *                                  _   _ ____  _
                      3:  *  Project                     ___| | | |  _ \| |
                      4:  *                             / __| | | | |_) | |
                      5:  *                            | (__| |_| |  _ <| |___
                      6:  *                             \___|\___/|_| \_\_____|
                      7:  *
                      8:  * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
                      9:  *
                     10:  * This software is licensed as described in the file COPYING, which
                     11:  * you should have received as part of this distribution. The terms
                     12:  * are also available at https://curl.haxx.se/docs/copyright.html.
                     13:  *
                     14:  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
                     15:  * copies of the Software, and permit persons to whom the Software is
                     16:  * furnished to do so, under the terms of the COPYING file.
                     17:  *
                     18:  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
                     19:  * KIND, either express or implied.
                     20:  *
                     21:  ***************************************************************************/
                     22: /* <DESC>
                     23:  * Shows how the write callback function can be used to download data into a
                     24:  * chunk of memory instead of storing it in a file.
                     25:  * </DESC>
                     26:  */
                     27: 
                     28: #include <stdio.h>
                     29: #include <stdlib.h>
                     30: #include <string.h>
                     31: 
                     32: #include <curl/curl.h>
                     33: 
                     34: struct MemoryStruct {
                     35:   char *memory;
                     36:   size_t size;
                     37: };
                     38: 
                     39: static size_t
                     40: WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
                     41: {
                     42:   size_t realsize = size * nmemb;
                     43:   struct MemoryStruct *mem = (struct MemoryStruct *)userp;
                     44: 
                     45:   char *ptr = realloc(mem->memory, mem->size + realsize + 1);
                     46:   if(ptr == NULL) {
                     47:     /* out of memory! */
                     48:     printf("not enough memory (realloc returned NULL)\n");
                     49:     return 0;
                     50:   }
                     51: 
                     52:   mem->memory = ptr;
                     53:   memcpy(&(mem->memory[mem->size]), contents, realsize);
                     54:   mem->size += realsize;
                     55:   mem->memory[mem->size] = 0;
                     56: 
                     57:   return realsize;
                     58: }
                     59: 
                     60: int main(void)
                     61: {
                     62:   CURL *curl_handle;
                     63:   CURLcode res;
                     64: 
                     65:   struct MemoryStruct chunk;
                     66: 
                     67:   chunk.memory = malloc(1);  /* will be grown as needed by the realloc above */
                     68:   chunk.size = 0;    /* no data at this point */
                     69: 
                     70:   curl_global_init(CURL_GLOBAL_ALL);
                     71: 
                     72:   /* init the curl session */
                     73:   curl_handle = curl_easy_init();
                     74: 
                     75:   /* specify URL to get */
                     76:   curl_easy_setopt(curl_handle, CURLOPT_URL, "https://www.example.com/");
                     77: 
                     78:   /* send all data to this function  */
                     79:   curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
                     80: 
                     81:   /* we pass our 'chunk' struct to the callback function */
                     82:   curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);
                     83: 
                     84:   /* some servers don't like requests that are made without a user-agent
                     85:      field, so we provide one */
                     86:   curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
                     87: 
                     88:   /* get it! */
                     89:   res = curl_easy_perform(curl_handle);
                     90: 
                     91:   /* check for errors */
                     92:   if(res != CURLE_OK) {
                     93:     fprintf(stderr, "curl_easy_perform() failed: %s\n",
                     94:             curl_easy_strerror(res));
                     95:   }
                     96:   else {
                     97:     /*
                     98:      * Now, our chunk.memory points to a memory block that is chunk.size
                     99:      * bytes big and contains the remote file.
                    100:      *
                    101:      * Do something nice with it!
                    102:      */
                    103: 
                    104:     printf("%lu bytes retrieved\n", (unsigned long)chunk.size);
                    105:   }
                    106: 
                    107:   /* cleanup curl stuff */
                    108:   curl_easy_cleanup(curl_handle);
                    109: 
                    110:   free(chunk.memory);
                    111: 
                    112:   /* we're done with libcurl, so clean it up */
                    113:   curl_global_cleanup();
                    114: 
                    115:   return 0;
                    116: }