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