C/C++使用libcurl库发送http请求（get和post可以用于请求html信息，也可以请求xml和json等串）

C++要实现http网络连接，需要借助第三方库，libcurl使用起来还是很方便的

环境：win32 + vs2015

如果要在Linux下使用，基本同理

1，下载编译libcurl

下载curl源码，找到vs工程，按照x86 x64 并对应debug和release编译出静态库lib

2，构建工程

1）curl头文件和lib拷贝到工程目录

2）配置附加包含目录libcurl中的include和附加库目录libcurl中的lib目录

3）添加预编译宏USE_OPENSSL和CURL_STATICLIB

4）添加如依赖库

crypt32.lib
ws2_32.lib
wldap32.lib
libcurl.lib

注意版本对应

3，代码示例

#include <iostream>
#include <string>
#include "curl/curl.h"
using namespace std;

#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "wldap32.lib")
#pragma comment(lib, "libcurl.lib")

// reply of the requery
size_t req_reply(void *ptr, size_t size, size_t nmemb, void *stream)
{
    cout << "----->reply" << endl;
    string *str = (string*)stream;
    cout << *str << endl;
    (*str).append((char*)ptr, size*nmemb);
    return size * nmemb;
}

// http GET
CURLcode curl_get_req(const std::string &url, std::string &response)
{
    // init curl
    CURL *curl = curl_easy_init();
    // res code
    CURLcode res;
    if (curl)
    {
        // set params
        curl_easy_setopt(curl, CURLOPT_URL, url.c_str()); // url
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false); // if want to use https
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false); // set peer and host verify false
        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, req_reply);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&response);
        curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
        curl_easy_setopt(curl, CURLOPT_HEADER, 1);
        curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3); // set transport and time out time
        curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
        // start req
        res = curl_easy_perform(curl);
    }
    // release curl
    curl_easy_cleanup(curl);
    return res;
}

// http POST
CURLcode curl_post_req(const string &url, const string &postParams, string &response)
{
    // init curl
    CURL *curl = curl_easy_init();
    // res code
    CURLcode res;
    if (curl)
    {
        // set params
        curl_easy_setopt(curl, CURLOPT_POST, 1); // post req
        curl_easy_setopt(curl, CURLOPT_URL, url.c_str()); // url
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postParams.c_str()); // params
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false); // if want to use https
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false); // set peer and host verify false
        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, req_reply);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&response);
        curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
        curl_easy_setopt(curl, CURLOPT_HEADER, 1);
        curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);
        curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
        // start req
        res = curl_easy_perform(curl);
    }
    // release curl
    curl_easy_cleanup(curl);
    return res;
}

int main()
{
    // global init
    curl_global_init(CURL_GLOBAL_ALL);

    // test get requery
    string getUrlStr = "http://cn.bing.com/images/trending?form=Z9LH";
    string getResponseStr;
    auto res = curl_get_req(getUrlStr, getResponseStr);
    if (res != CURLE_OK)
        cerr << "curl_easy_perform() failed: " + string(curl_easy_strerror(res)) << endl;
    else
        cout << getResponseStr << endl;

    // test post requery
    string postUrlStr = "https://www.baidu.com/s";
    string postParams = "f=8&rsv_bp=1&rsv_idx=1&word=picture&tn=98633779_hao_pg";
    string postResponseStr;
    auto res = curl_post_req(postUrlStr, postParams, postResponseStr);
    if (res != CURLE_OK)
        cerr << "curl_easy_perform() failed: " + string(curl_easy_strerror(res)) << endl;
    else
        cout << postResponseStr << endl;

    // global release
    curl_global_cleanup();
    system("pause");
    return 0;
}

• get和post可以用于请求html信息，也可以请求xml和json等串
• 可以添加自定义的header 域和cookies
• 这是libcurl的简单接口，基本等同于阻塞试请求，libcurl有高阶的异步并发接口，运用更复杂

http://blog.csdn.net/u012234115/article/details/71371962