使用curl 下载HTML

简单的一个curl小例子：

#include <iostream>

#include <string>

#include <sstream>

#include <curl/curl.h>

#include <string.h>

#define BUF_SIZE 1024 * 100

using namespace std;
string DownloadString(char* url);

int main(int argc, const char* argv[]){
curl_global_init(CURL_GLOBAL_ALL);

    cout <<DownloadString("http://www.baidu.com/");

    cin.get();

    curl_global_cleanup();

    return 0;

}
int WriteData(char* in, size_t size, size_t nmemb,  string* out){

    out->append(in);

    return size*nmemb;

}
string DownloadString(char* url){

    string buffer;

    string headerData;

    CURL* conn;

    curl_slist* header = NULL;

    header = curl_slist_append(header, "Accept-Encoding: gzip, deflate");

    header = curl_slist_append(header, "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; CIBA)");

    header = curl_slist_append(header, "Connection: Keep-Alive");
conn = curl_easy_init();

    curl_easy_setopt(conn, CURLoption::CURLOPT_URL, url);

    curl_easy_setopt(conn, CURLoption::CURLOPT_HTTPHEADER, header);

    curl_easy_setopt(conn, CURLoption::CURLOPT_ACCEPT_ENCODING, "gzip");

    curl_easy_setopt(conn, CURLoption::CURLOPT_WRITEDATA, &buffer);

    curl_easy_setopt(conn, CURLoption::CURLOPT_WRITEFUNCTION, WriteData);

    curl_easy_setopt(conn, CURLoption::CURLOPT_WRITEHEADER, &headerData);
CURLcode code = curl_easy_perform(conn);

    if (code != CURLcode::CURLE_OK)

        return "";

    curl_slist_free_all(header);

    curl_easy_cleanup(conn);
istringstream istream(headerData.c_str());

    string out;

    bool isgzip = false;

    while (istream.good())

    {

        getline(istream, out, ‘\n‘);

        if (!out.empty()){

            if (out.find("Content-Encoding") != out.npos && out.find("gzip") != out.npos){

                isgzip = true;

            }

        }

    }
///gzip

    return buffer;

}

该例子通过curl下载百度首页html与响应头信息，并自动对gzip解码。