libcurl使用演示样例
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 X-Powered-By: HPHP Server: BWS/1.1 BDPAGETYPE: 1 BDQID: 0x9fcc512a0001374f BDUSERID: 0 X-Cache: MISS from qplus_wanproxy_pub_fy1 Via: 1.0 qplus_wanproxy_pub_fy1 (squid/3.1.18) Connection: close <!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;width:100%;margin:0 auto; ......