C++使用libcurl做HttpClient

标签： c++stringnullsslheaderurl

2012-06-14 19:25 45469人阅读 评论(19) 收藏 举报

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    当使用C++做HTTP客户端时，目前通用的做法就是使用libcurl。其官方网站的地址是http://curl.haxx.se/，该网站主要提供了Curl和libcurl。Curl是命令行工具，用于完成FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE 以及 LDAP的命令的请求及接收回馈。libcurl提供给开发者，用于使用C++跨平台的开发各种网络协议的请求及响应。里面的文档非常齐全，不过都是英文的。

    本文提供最简单的demo使用libcurl开发HttpClient。主要包括同步的HTTP GET、HTTP POST、HTTPS GET、HTTPS POST。

    下载libcurl包，如果使用Linux平台，建议下载源文件编译；如果使用Windows平台，建议下载Win32 - MSVC，下载地址是：http://curl.haxx.se/download.html

#ifndef __HTTP_CURL_H__#define __HTTP_CURL_H__#include <string>class CHttpClient{public:CHttpClient(void);~CHttpClient(void);public:/*** @brief HTTP POST请求* @param strUrl 输入参数,请求的Url地址,如:http://www.baidu.com* @param strPost 输入参数,使用如下格式para1=val1¶2=val2&…* @param strResponse 输出参数,返回的内容* @return 返回是否Post成功*/int Post(const std::string & strUrl, const std::string & strPost, std::string & strResponse);/*** @brief HTTP GET请求* @param strUrl 输入参数,请求的Url地址,如:http://www.baidu.com* @param strResponse 输出参数,返回的内容* @return 返回是否Post成功*/int Get(const std::string & strUrl, std::string & strResponse);/*** @brief HTTPS POST请求,无证书版本* @param strUrl 输入参数,请求的Url地址,如:https://www.alipay.com* @param strPost 输入参数,使用如下格式para1=val1¶2=val2&…* @param strResponse 输出参数,返回的内容* @param pCaPath 输入参数,为CA证书的路径.如果输入为NULL,则不验证服务器端证书的有效性.* @return 返回是否Post成功*/int Posts(const std::string & strUrl, const std::string & strPost, std::string & strResponse, const char * pCaPath = NULL);/*** @brief HTTPS GET请求,无证书版本* @param strUrl 输入参数,请求的Url地址,如:https://www.alipay.com* @param strResponse 输出参数,返回的内容* @param pCaPath 输入参数,为CA证书的路径.如果输入为NULL,则不验证服务器端证书的有效性.* @return 返回是否Post成功*/int Gets(const std::string & strUrl, std::string & strResponse, const char * pCaPath = NULL);public:void SetDebug(bool bDebug);private:bool m_bDebug;};#endif

#include "httpclient.h"#include "curl/curl.h"#include <string>CHttpClient::CHttpClient(void) : m_bDebug(false){}CHttpClient::~CHttpClient(void){}static int OnDebug(CURL *, curl_infotype itype, char * pData, size_t size, void *){if(itype == CURLINFO_TEXT){//printf("[TEXT]%s\n", pData);}else if(itype == CURLINFO_HEADER_IN){printf("[HEADER_IN]%s\n", pData);}else if(itype == CURLINFO_HEADER_OUT){printf("[HEADER_OUT]%s\n", pData);}else if(itype == CURLINFO_DATA_IN){printf("[DATA_IN]%s\n", pData);}else if(itype == CURLINFO_DATA_OUT){printf("[DATA_OUT]%s\n", pData);}return 0;}static size_t OnWriteData(void* buffer, size_t size, size_t nmemb, void* lpVoid){std::string* str = dynamic_cast<std::string*>((std::string *)lpVoid);if( NULL == str || NULL == buffer ){return -1;}    char* pData = (char*)buffer;    str->append(pData, size * nmemb);return nmemb;}int CHttpClient::Post(const std::string & strUrl, const std::string & strPost, std::string & strResponse){CURLcode res;CURL* curl = curl_easy_init();if(NULL == curl){return CURLE_FAILED_INIT;}if(m_bDebug){curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);}curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());curl_easy_setopt(curl, CURLOPT_POST, 1);curl_easy_setopt(curl, CURLOPT_POSTFIELDS, strPost.c_str());curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);res = curl_easy_perform(curl);curl_easy_cleanup(curl);return res;}int CHttpClient::Get(const std::string & strUrl, std::string & strResponse){CURLcode res;CURL* curl = curl_easy_init();if(NULL == curl){return CURLE_FAILED_INIT;}if(m_bDebug){curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);}<pre name="code" class="cpp">curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);/*** 当多个线程都使用超时处理的时候，同时主线程中有sleep或是wait等操作。* 如果不设置这个选项，libcurl将会发信号打断这个wait从而导致程序退出。*/curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);res = curl_easy_perform(curl);curl_easy_cleanup(curl);return res;}int CHttpClient::Posts(const std::string & strUrl, const std::string & strPost, std::string & strResponse, const char * pCaPath){CURLcode res;CURL* curl = curl_easy_init();if(NULL == curl){return CURLE_FAILED_INIT;}if(m_bDebug){curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);}curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());curl_easy_setopt(curl, CURLOPT_POST, 1);curl_easy_setopt(curl, CURLOPT_POSTFIELDS, strPost.c_str());curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);if(NULL == pCaPath){curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);}else{//缺省情况就是PEM，所以无需设置，另外支持DER//curl_easy_setopt(curl,CURLOPT_SSLCERTTYPE,"PEM");curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, true);curl_easy_setopt(curl, CURLOPT_CAINFO, pCaPath);}curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);res = curl_easy_perform(curl);curl_easy_cleanup(curl);return res;}int CHttpClient::Gets(const std::string & strUrl, std::string & strResponse, const char * pCaPath){CURLcode res;CURL* curl = curl_easy_init();if(NULL == curl){return CURLE_FAILED_INIT;}if(m_bDebug){curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);}curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);if(NULL == pCaPath){curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);}else{curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, true);curl_easy_setopt(curl, CURLOPT_CAINFO, pCaPath);}curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);res = curl_easy_perform(curl);curl_easy_cleanup(curl);return res;}///////////////////////////////////////////////////////////////////////////////////////////////void CHttpClient::SetDebug(bool bDebug){m_bDebug = bDebug;}