Re: Web pages extraction & Libcurl

From:
 Choi <Evil.Choi@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 09 Nov 2007 11:54:05 -0000
Message-ID:
<1194609245.995551.277380@s15g2000prm.googlegroups.com>
On Nov 9, 11:50 am, Choi <Evil.C...@gmail.com> wrote:

Good morning.

I've tried to extract, using libcurl, web pages but it failed. There
is no compilation error concerning the class I wrote, but the problems
appear when I compile a main method which calls this class.

My class :

**********************************libcurl_tools.h

#include <curl/curl.h>

struct MemoryStruct {
        char *memory;
        size_t size;

};

class libcurl_tools {

        CURL * curl_handle;
        MemoryStruct chunk;

        public:

        libcurl_tools();
        void init();
        bool close();
        void set_referrer(std::string, CURL *);
        std::string perform(std::string, CURL *);

};

**********************************libcurl_tools.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>

#include <iostream> // pour std::cout
#include <string> // pour std::string

#include "libcurl_tools.h"

libcurl_tools::libcurl_tools() {}

static void *myrealloc(void *ptr, size_t size)
{
        /* There might be a realloc() out there that doesn't like realloc=

ing

           NULL pointers, so we take care of it here */
        if(ptr)
                return realloc(ptr, size);
        else
                return malloc(size);

}

static size_t WriteMemoryCallback(void *ptr, size_t size, size_t
nmemb, void *data)
{
        size_t realsize = size * nmemb;
        struct MemoryStruct *mem = (struct MemoryStruct *)data;

        mem->memory = (char *)myrealloc(mem->memory, mem->size + realsi=

ze +

1);
        if (mem->memory) {
                memcpy(&(mem->memory[mem->size]), ptr, realsize);
                mem->size += realsize;
                mem->memory[mem->size] = 0;
        }
        return realsize;

}

void libcurl_tools::set_referrer(std::string referer, CURL
*curl_handle ) {

        curl_easy_setopt(curl_handle, CURLOPT_REFERER, referer.c_str());

}

//initialise la connection
void libcurl_tools::init() {

        chunk.memory=NULL; /* we expect realloc(NULL, size) to work */
        chunk.size = 0; /* no data at this point */

        curl_global_init(CURL_GLOBAL_ALL);

        /* init the curl session */
        curl_handle = curl_easy_init();

}

//t=E9l=E9charge l'url en argument
std::string libcurl_tools::perform(std::string url , CURL
*curl_handle) {

        /* specify URL to get */
        curl_easy_setopt(curl_handle, CURLOPT_URL, url.c_str());

        /* send all data to this function */
        curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION,
WriteMemoryCallback);

        /* we pass our 'chunk' struct to the callback function */
        curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);

        /* some servers don't like requests that are made without a user-
agent
           field, so we provide one */
        curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/
1.0");

        /* get it! */
        curl_easy_perform(curl_handle);

        /* cleanup curl stuff */
        curl_easy_cleanup(curl_handle);

        /*
         * Now, our chunk.memory points to a memory block that is chunk.s=

ize

         * bytes big and contains the remote file.
         *
         * Do something nice with it!
         *
         * You should be aware of the fact that at this point we might ha=

ve

an
         * allocated data block, and nothing has yet deallocated that dat=

a.

So when
         * you're done with it, you should free() it as a nice applicatio=

n.

         */

        //return chunk.memory; // les 2 ont l'air de marcher (pour le
moment...)
        return std::string(chunk.memory);

}

bool libcurl_tools::close() {

        if(chunk.memory)
                free(chunk.memory);

        return 0;

}

*********************************** test.cpp which includes the main()

#include <iostream>
#include <string>
#include <sstream>
#include "libcurl_tools.h"

//#include <stdio.h>

using namespace std;

int main()
{

 libcurl_tools e();

    e.init();

    std::string chaine;
    std:: string s = "www.yahoo.com";

 chaine = e.perform(s);

   e.close();

}

There are 3 compilation errors concerning the calls of init(),
perform() and close() methods, and I really don't know why it happens.
I wish you could help me guys...

Thanks


If it can help, the errors are similar to :

 test.cpp:91: erreur: request for member =ABinit" in =ABe", which is of
non-class type =ABlibcurl_tools ()()"

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