C++使用libcurl做HttpClient

夢醉千秋 2015-06-17

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當使用C++做HTTP客戶端時，目前通用的做法就是使用libcurl,。其官方網(wǎng)站的地址是http://curl./,，該網(wǎng)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的命令的請求及接收回饋,。libcurl提供給開發(fā)者，用于使用C++跨平臺的開發(fā)各種網(wǎng)絡(luò)協(xié)議的請求及響應(yīng),。里面的文檔非常齊全,，不過都是英文的。

本文提供最簡單的demo使用libcurl開發(fā)HttpClient,。主要包括同步的HTTP GET,、HTTP POST、HTTPS GET,、HTTPS POST,。

下載libcurl包，如果使用Linux平臺,，建議下載源文件編譯,；如果使用Windows平臺，建議下載Win32 - MSVC,，下載地址是：http://curl./download.html

#ifndef __HTTP_CURL_H__  
#define __HTTP_CURL_H__  
#include <string>  
class CHttpClient  
{  
public:  
    CHttpClient(void);  
    ~CHttpClient(void);  
public:  
    /** 
    * @brief HTTP POST請求 
    * @param strUrl 輸入?yún)?shù),請求的Url地址,如:http://www.baidu.com 
    * @param strPost 輸入?yún)?shù),使用如下格式para1=val1?2=val2&… 
    * @param strResponse 輸出參數(shù),返回的內(nèi)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請求 
    * @param strUrl 輸入?yún)?shù),請求的Url地址,如:http://www.baidu.com 
    * @param strResponse 輸出參數(shù),返回的內(nèi)容 
    * @return 返回是否Post成功 
    */  
    int Get(const std::string & strUrl, std::string & strResponse);  
    /** 
    * @brief HTTPS POST請求,無證書版本 
    * @param strUrl 輸入?yún)?shù),請求的Url地址,如:https://www.alipay.com 
    * @param strPost 輸入?yún)?shù),使用如下格式para1=val1?2=val2&… 
    * @param strResponse 輸出參數(shù),返回的內(nèi)容 
    * @param pCaPath 輸入?yún)?shù),為CA證書的路徑.如果輸入為NULL,則不驗證服務(wù)器端證書的有效性. 
    * @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請求,無證書版本 
    * @param strUrl 輸入?yún)?shù),請求的Url地址,如:https://www.alipay.com 
    * @param strResponse 輸出參數(shù),返回的內(nèi)容 
    * @param pCaPath 輸入?yún)?shù),為CA證書的路徑.如果輸入為NULL,則不驗證服務(wù)器端證書的有效性. 
    * @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 plaincopy
#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);  
    /** 
    * 當多個線程都使用超時處理的時候,，同時主線程中有sleep或是wait等操作。 
    * 如果不設(shè)置這個選項,，libcurl將會發(fā)信號打斷這個wait從而導(dǎo)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  
    {  
        //缺省情況就是PEM，所以無需設(shè)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;  
}