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C++使用libcurl做HttpClient

2014-01-25 13:37 369 查看
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

[cpp] view
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#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

[cpp] view
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#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;

}
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