简要说明：C++使用libcurl訪问"www.baidu.com"。获取返回码和打印出http文件
/*
* @ libcurl使用演示样例
* @ 2014.04.29
* @ g++ -o LibCurlFunc LibCurlFunc.cpp -lcurl
*/
#include <iostream>
#include <string.h>
#include <curl/curl.h>
using namespace std;
/*
Http请求结束的回调函数
@ 会被调用多次，有下载到数据(http文件)就回调。直到下载完
*/
static size_t WriteFunction(void *input, size_t uSize, size_t uCount, void *avg)
{
/* cout << "[WriteFunction]:" << endl
<< "input=" << (char*)input << endl
<< "elementSize=" << uSize << endl
<< "elementCount=" << uCount << endl;*/
// 将请求返回数据input复制到avg中(avg为一開始curl_easy_setopt设置的參)
size_t uLen = uSize*uCount;
// string &sBuffer = *reinterpret_cast<string *>(avg);
// sBuffer.append(reinterpret_cast<const char *>(input), uLen);
string *pStr = (string *)(avg);
pStr->append((char *)(input), uLen);
// 仅仅有返回uSize*uCount才会返回成功
return uLen;
}
int main()
{
CURL *pCurl = NULL;
CURLcode code;
/* CURLcode curl_global_init(long flags)
@ 初始化libcurl。全局仅仅需调一次
@ flags: CURL_GLOBAL_DEFAULT // 等同于CURL_GLOBAL_ALL
CURL_GLOBAL_ALL // 初始化全部的可能的调用
CURL_GLOBAL_SSL // 初始化支持安全套接字层
CURL_GLOBAL_WIN32 // 初始化win32套接字库
CURL_GLOBAL_NOTHING // 没有额外的初始化
......
*/
code = curl_global_init(CURL_GLOBAL_DEFAULT);
if (code != CURLE_OK) {
cout << "curl_global_init() Err" << endl;
return -1;
}
/* CURL *curl_easy_init()
@ 初始化curl生成CURL *curl指针
*/
pCurl = curl_easy_init();
if (pCurl == NULL) {
cout << "curl_easy_init() Err" << endl;
return -1;
}
string sUrl = "www.baidu.com";
curl_slist *pHeaders = NULL;
string sBuffer;
/* struct curl_slist *curl_slist_append(struct curl_slist * list, const char * string);
@ 加入Http消息头
@ 属性string：形式为name+": "+contents
*/
string header = "username: andyawang";
pHeaders = curl_slist_append(pHeaders, header.c_str());
/* CURLcode curl_easy_setopt(CURL *handle, CURLoption option, parameter);
@ 设置下载属性及经常使用參数
*/
curl_easy_setopt(pCurl, CURLOPT_URL, "www.baidu.com"); // 訪问的URL
curl_easy_setopt(pCurl, CURLOPT_HTTPHEADER, pHeaders); // 属性头部(要不pHeader就没用了)
curl_easy_setopt(pCurl, CURLOPT_TIMEOUT, 20); // 超时(单位S)
curl_easy_setopt(pCurl, CURLOPT_HEADER, 1); // 下载数据包含HTTP头部
curl_easy_setopt(pCurl, CURLOPT_WRITEFUNCTION, &WriteFunction); // !数据回调函数
curl_easy_setopt(pCurl, CURLOPT_WRITEDATA, &sBuffer); // !数据回调函数的參。一般为Buffer或文件fd
/* CURLcode curl_easy_perform(CURL *handle);
@ 開始下载
*/
code = curl_easy_perform(pCurl);
if (code != CURLE_OK) {
cout << "curl_easy_perform() Err" << endl;
return -1;
}
/* CURLcode curl_easy_getinfo(CURL *curl, CURLINFO info, ... );
@ 获取下载完的相关信息
@ info：CURLINFO_RESPONSE_CODE // 获取返回的Http码
CURLINFO_TOTAL_TIME // 获取总的请求下载时间
CURLINFO_SIZE_DOWNLOAD // 获取下载的文件大小
......
*/
long retCode = 0;
code = curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE , &retCode);
if (code != CURLE_OK) {
cout << "curl_easy_perform() Err" << endl;
return -1;
}
cout << "[Http Return Code] : " << retCode << endl;
cout << "[Http Context] : " << endl << sBuffer << endl;
/* void curl_easy_cleanup(CURL * handle);
@ 释放CURL *curl指针
*/
curl_easy_cleanup(pCurl);
/* void curl_global_cleanup(void);
@ 初始化libcurl，全局也仅仅需调一次
*/
curl_global_cleanup();
}
执行结果：
gapp_devnet_1:/data/home/andyawang/code/Components/Http # g++ -o LibCurlFunc LibCurlFunc.cpp -lcurl
gapp_devnet_1:/data/home/andyawang/code/Components/Http # ./LibCurlFunc
[Http Return Code] : 200
[Http Context] :
HTTP/1.0 200 OK
Date: Wed, 30 Apr 2014 02:41:35 GMT
Content-Type: text/html; charset=utf-8
Vary: Accept-Encoding
Set-Cookie: BAIDUID=8DD8F93E631536AD6CDC010E1A52507C:FG=1; expires=Thu, 31-Dec-37 23:55:55 GMT; max-age=2147483647; path=/; domain=.baidu.com
Set-Cookie: BDSVRTM=0; path=/
Set-Cookie: H_PS_PSSID=5695_1428_5225_6024_4760_6018_6256_6311_6269; path=/; domain=.baidu.com
P3P: CP=" OTI DSP COR IVA OUR IND COM "
Cache-Control: private
Expires: Wed, 30 Apr 2014 02:41:33 GMT
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<!DOCTYPE html><!--STATUS OK--><html><head><meta http-equiv="content-type" content="text/html;charset=utf-8"><link rel="dns-prefetch" href="//s1.bdstatic.com"/><link rel="dns-prefetch" href="//t1.baidu.com"/><link rel="dns-prefetch" href="//t2.baidu.com"/><link rel="dns-prefetch" href="//t3.baidu.com"/><link rel="dns-prefetch" href="//t10.baidu.com"/><link rel="dns-prefetch" href="//t11.baidu.com"/><link rel="dns-prefetch" href="//t12.baidu.com"/><title>百度一下。你就知道</title><style >html,body{height:100%}html{overflow-y:auto}#wrapper{position:relative;_position:;min-height:100%}#content{padding-bottom:100px;text-align:center}#ftCon{height:100px;position:absolute;bottom:44px;text-align:center;100%;margin:0 auto;
......