curl_test

#include <iostream>
#include <string>
#include <functional>
#include <curl/curl.h>

using namespace std;

static char errorBuffer[CURL_ERROR_SIZE];
static string buffer;

// This callback function gets called by libcurl as soon as there is data
// received that needs to be saved. ptr points to the delivered data,
// and the size of that data is size multiplied with nmemb.
static int writer(char * ptr_data, size_t size, size_t nmemb, string * writerData)
{
    if(writerData == NULL)
        return 0;

    size_t data_size = size * nmemb;
    writerData->append(ptr_data, data_size);

    return (int)data_size;
}

static bool init(CURL *& conn, const char * url)
{
    CURLcode code;
    conn = curl_easy_init();

    if(conn == NULL)
    {
        fprintf(stderr, "Failed to create CURL connection\n");

        exit(EXIT_FAILURE);
    }

    code = curl_easy_setopt(conn, CURLOPT_ERRORBUFFER, errorBuffer);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set error buffer [%d]\n", code);

        return false;
    }

    code = curl_easy_setopt(conn, CURLOPT_URL, url);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set URL [%s]\n", errorBuffer);

        return false;
    }

    code = curl_easy_setopt(conn, CURLOPT_SSL_VERIFYPEER, 1L);
    if(code != CURLE_OK)
    {
        fprintf(
            stderr, "Failed to set CURLOPT_SSL_VERIFYPEER [%s]\n", errorBuffer);

        return false;
    }

    code = curl_easy_setopt(conn, CURLOPT_COOKIEFILE, "");
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set CURLOPT_COOKIEFILE [%s]\n", errorBuffer);

        return false;
    }

    code = curl_easy_setopt(conn, CURLOPT_FOLLOWLOCATION, 1L);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set redirect option [%s]\n", errorBuffer);

        return false;
    }

    auto callback = [](char * ptr_data, size_t size, size_t nmemb, string * writerData)
        ->size_t
        {
            if(writerData == NULL)
                return 0;
            size_t data_size = size * nmemb;
            writerData->append(ptr_data, data_size);
            return (int)data_size;
        };

    code = curl_easy_setopt(conn, CURLOPT_WRITEFUNCTION, callback);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set writer [%s]\n", errorBuffer);

        return false;
    }

    code = curl_easy_setopt(conn, CURLOPT_WRITEDATA, &buffer);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set write data [%s]\n", errorBuffer);

        return false;
    }

    return true;
}

int main(int argc, char * argv[])
{
    CURL * conn = NULL;
    CURLcode code;

    code = curl_global_init(CURL_GLOBAL_DEFAULT);
    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to init curl [%d]\n", code);

        return false;
    }

    // Initialize CURL connection

    if(!init(conn, "http://www.google.com/"))
    {
        fprintf(stderr, "Connection initializion failed\n");

        exit(EXIT_FAILURE);
    }

    // Retrieve content for the URL

    code = curl_easy_perform(conn);
    curl_easy_cleanup(conn);

    if(code != CURLE_OK)
    {
        fprintf(stderr, "Failed to get '%s' [%s]\n", argv[1], errorBuffer);

        exit(EXIT_FAILURE);
    }

    cout << buffer;

    return EXIT_SUCCESS;
}