利用curl来做http访问(支持session,cookie)

/* curl_httpget.h */

#ifndef CURL_HTTPGET_H
#define CURL_HTTPGET_H

struct MemoryStruct {
  char *memory;
  size_t size;
};

int curl_httpget(const char* URLbuf,struct MemoryStruct *chunk,const char* cookiefile);

#endif

/*  curl_httpget.cpp   */
#include
#include
#include
#include "curl_httpget.h"
#include

void *myrealloc(void *ptr, size_t size)
{
  /* There might be a realloc() out there that doesn't like reallocing
     NULL pointers, so we take care of it here */
  if(ptr)
    return realloc(ptr, size);
  else
    return malloc(size);
}

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

int curl_httpget(const char* URLbuf,struct MemoryStruct *chunk,const char* cookiefile)
{
  CURL *curl_handle;
  int errcode=0; 
  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();
  curl_easy_setopt(curl_handle, CURLOPT_URL, URLbuf);
  curl_easy_setopt(curl_handle, CURLOPT_COOKIEFILE,cookiefile);
  /* 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); 
  curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
  curl_easy_setopt(curl_handle, CURLOPT_COOKIEJAR,cookiefile);   
  /* get it! */
  errcode=curl_easy_perform(curl_handle); 
   /* cleanup curl stuff */
  curl_easy_cleanup(curl_handle);

  return errcode; 

}

用法：  
  errcode= curl_httpget(URLbuf,&chunk,cookiefile);
   if(!errcode){
    int min=sizeof(content)>chunk.size?chunk.size:sizeof(content);  
    strncpy(content,chunk.memory,min);
   }else{
        strcpy(content,"");
   }  
   if(chunk.memory) free(chunk.memory);