LibCurl库使用

这篇文章以实例讲解如何使用HTTP常用的四种协议 put、post、get、delete，只要掌握一种，其他的在使用上都是大同小异。在实际项目开发过程中，这些工具会有帮助，HttpWatch或者Wireshark。最新的libcurl可以到http://curl.haxx.se/下载。关于资料可以参考官方文档。

库使用前准备工作：

引用lib库，并把文件夹curl复制到到工程项目目录中。代码部分如下：

#pragma comment (lib, "libcurl.lib" )
#pragma comment (lib, "libcurl_imp.lib" )

使用：

宏：

#define HTTPHEADER_CONTENTTYPE "Content-Type: application/json"
#define HTTPHEADER_ACCEPTLANGUAGE "Accept-Language: zh-cn"
#define HTTPHEADER_ACCEPT "Accept: application/json"
#define HTTPHEADER_TRANSFERENCODING "Transfer-Encoding:"
#define HTTPHEADER_EXPECT "Expect:"
#define HTTPHEADER_CONTENTLENGTH0 "Content-Length: 0"

回调函数：

size_t PutWriteFunCallBack(void *buffer, size_t size, size_t nmemb, void *stream) 
{ 
	//EnterCriticalSection(&m_csPutFunCallBack);

	char *cRev = (char*)stream;
	char *buf = (char*)buffer;
	if (CString(buf).Find("{\"message\":") >= 0)
	{
		//strResponseJson = rev;
		strcpy(cRev, buf);
	}

	size_t ret = size * nmemb;

	//LeaveCriticalSection(&m_csPutFunCallBack); 

	return ret;	
}

PUT

//=======================================================
// 函 数 名：DoHttpPut
// 功能描述：DoHttpPut
// 输入参数：strUrl:完整的路径，如登录接口
//					http://10.166.46.169:8000/agentgateway/resource//onlineagent/104
//			 strBody:报文中的body，json格式，如：
/*			 "\r\n{\r\n\"password\":\"\",\r\n\"phonenum\":\"7106\",\r\n\"autoanswer\":\"true\"
,\r\n\"autoenteridle\":\"true\",\r\n\"releasephone\":\"true\",\r\n\"status\":4\r\n}"
*/
// 输出参数：
// 返回参数：
// 创建日期：2013.01.22
// 修改日期：2013.01.22
// 作    者：
// 附加说明：
//========================================================
CString CRESTFulBase::DoHttpPut(CString strUrl, CString strBody)
{
	CString strRet("");

	char cRev[LIBCURL_REVSIZE];
	memset(cRev, 0, LIBCURL_REVSIZE);

	CURL *m_curl = NULL;
	m_curl = ::curl_easy_init();

	if (NULL == m_curl)
	{
		return ERROR_LIBCURL;
	}

	//::curl_easy_reset(m_curl);

	//要截取的字符串"http://10.166.46.169:8000/agentgateway/resource//onlineagent/106"
	//strResponseJson = "";
	CString strHostHeader = GetHostHeaderStr(strUrl);
	int iBodyLen = strBody.GetLength();
	CString strContentLenHeader("");
	strContentLenHeader.Format("Content-Length: %d", iBodyLen);

	::curl_easy_setopt(m_curl, CURLOPT_URL, strUrl);
	::curl_easy_setopt(m_curl, CURLOPT_PUT, 1);
	::curl_easy_setopt(m_curl, CURLOPT_WRITEFUNCTION, PutWriteFunCallBack);
	::curl_easy_setopt(m_curl, CURLOPT_WRITEDATA, cRev);
	::curl_easy_setopt( m_curl, CURLOPT_TIMEOUT, m_iTimeOut);

	struct curl_slist *headers = NULL;
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTTYPE);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPTLANGUAGE);
	headers = curl_slist_append(headers, strHostHeader);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPT);
	headers = curl_slist_append(headers, HTTPHEADER_TRANSFERENCODING);
	headers = curl_slist_append(headers, strContentLenHeader);
	headers = curl_slist_append(headers, HTTPHEADER_EXPECT);
	headers = curl_slist_append(headers, strBody);
	::curl_easy_setopt(m_curl, CURLOPT_HTTPHEADER, headers);

	CURLcode ret = curl_easy_perform(m_curl);

	::curl_easy_cleanup(m_curl);

	if(0 == strlen(cRev))
	{
		strRet = ERROR_LIBCURL;
	}
	else
	{
		strRet = GetJson(cRev);
	}

	return strRet;
}

POST

CString CRESTFulBase::DoHttpPost(CString strUrl, CString strBody)
{
	CString strRet("");

	char cRev[LIBCURL_REVSIZE];
	memset(cRev, 0, LIBCURL_REVSIZE);

	CURL *m_curl = NULL;
	m_curl = ::curl_easy_init();

	if (NULL == m_curl)
	{
		return ERROR_LIBCURL;
	}

	//要截取的字符串"http://10.166.46.169:8000/agentgateway/resource//onlineagent/106"
	//strResponseJson = "";
	CString strHostHeader = GetHostHeaderStr(strUrl);
	int iBodyLen = strBody.GetLength();
	CString strContentLenHeader("");
	strContentLenHeader.Format("Content-Length: %d", iBodyLen);

	::curl_easy_setopt(m_curl, CURLOPT_URL, strUrl);
	::curl_easy_setopt(m_curl, CURLOPT_POST, 1);
	::curl_easy_setopt(m_curl, CURLOPT_WRITEFUNCTION, PutWriteFunCallBack);
	::curl_easy_setopt(m_curl, CURLOPT_WRITEDATA, cRev);
	::curl_easy_setopt( m_curl, CURLOPT_TIMEOUT, m_iTimeOut);

	struct curl_slist *headers = NULL;
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTTYPE);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPTLANGUAGE);
	headers = curl_slist_append(headers, strHostHeader);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPT);
	headers = curl_slist_append(headers, HTTPHEADER_TRANSFERENCODING);
	headers = curl_slist_append(headers, strContentLenHeader);
	headers = curl_slist_append(headers, HTTPHEADER_EXPECT);
	headers = curl_slist_append(headers, strBody);
	::curl_easy_setopt(m_curl, CURLOPT_HTTPHEADER, headers);

	CURLcode ret = curl_easy_perform(m_curl);

	::curl_easy_cleanup(m_curl);

	if(0 == strlen(cRev))
	{
		strRet = ERROR_LIBCURL;
	}
	else
	{
		strRet = GetJson(cRev);
	}

	return strRet;
}

GET

 

//=======================================================
// 函 数 名：DoHttpGet
// 功能描述：DoHttpGet
// 输入参数：strUrl:完整的路径，如强制签出接口
//					"http://10.166.46.169:8000/agentgateway/resource//onlineagent/104/forcelogout"
//			 iFlag:0,普通请求；1，轮询接口事件
// 输出参数：
// 返回参数：
// 创建日期：
// 修改日期：
// 作    者：
// 附加说明：
//========================================================
CString CRESTFulBase::DoHttpGet(CString strUrl, int iFlag)
{
	EnterCriticalSection(&m_csHttpGet);

	CString strRet("");

	char cRev[LIBCURL_REVSIZE];
	memset(cRev, 0, LIBCURL_REVSIZE);

	CURL *m_curl = NULL;
	m_curl = ::curl_easy_init();

	if (NULL == m_curl)
	{
		return ERROR_LIBCURL;
	}

	//::curl_easy_reset(m_curl);

	//要截取的字符串"http://10.166.46.169:8000/agentgateway/resource//onlineagent/106"
	//strResponseJson = "";
	CString strHostHeader = GetHostHeaderStr(strUrl);

	::curl_easy_setopt(m_curl, CURLOPT_URL, strUrl);
	::curl_easy_setopt(m_curl, CURLOPT_HTTPGET, 1);
	::curl_easy_setopt(m_curl, CURLOPT_TIMEOUT, m_iTimeOut);
	if(0 == iFlag)
	{
		::curl_easy_setopt(m_curl, CURLOPT_WRITEFUNCTION, PutWriteFunCallBack);
		::curl_easy_setopt(m_curl, CURLOPT_WRITEDATA, cRev);
	}
	else if(1 == iFlag)
	{
		CLog log;
		log.WriteLog(0, "%s", "DoHttpGet");

		::curl_easy_setopt(m_curl, CURLOPT_WRITEFUNCTION, EventWriteFunCallBack);
		::curl_easy_setopt(m_curl, CURLOPT_WRITEDATA, cRev);
	}

	struct curl_slist *headers = NULL;
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTTYPE);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPTLANGUAGE);
	headers = curl_slist_append(headers, strHostHeader);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPT);
	headers = curl_slist_append(headers, HTTPHEADER_TRANSFERENCODING);
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTLENGTH0);
	headers = curl_slist_append(headers, HTTPHEADER_EXPECT);

	::curl_easy_setopt(m_curl, CURLOPT_HTTPHEADER, headers);

	CURLcode ret = curl_easy_perform(m_curl);

	::curl_easy_cleanup(m_curl);

	if(0 == strlen(cRev))
	{
		strRet = ERROR_LIBCURL;
	}
	else
	{
		strRet = GetJson(cRev);
		
		//有事件从服务器返回。
		if (strRet.Find("\"event\":{") > 0)
		{
			DispatchEventMsg(strRet);
		}

	}

	return strRet;

	LeaveCriticalSection(&m_csHttpGet); 
}

DELETE

//=======================================================
// 函 数 名：DoHttpDelete
// 功能描述：DoHttpDelete
// 输入参数：strUrl:完整的路径，如强制签出接口
//					"http://10.166.46.169:8000/agentgateway/resource//onlineagent/104/forcelogout"
// 输出参数：
// 返回参数：
// 创建日期：2013.01.24
// 修改日期：2013.01.24
// 作      者：
// 附加说明：
//========================================================
CString CRESTFulBase::DoHttpDelete(CString strUrl)
{	
	CString strRet("");

	char cRev[LIBCURL_REVSIZE];
	memset(cRev, 0, LIBCURL_REVSIZE);

	CURL *m_curl = NULL;
	m_curl = ::curl_easy_init();

	if (NULL == m_curl)
	{
		return ERROR_LIBCURL;
	}

	//::curl_easy_reset(m_curl);

	//要截取的字符串"http://10.166.46.169:8000/agentgateway/resource//onlineagent/106"
	//http://10.166.46.169:8000/agentgateway/resource//onlineagent/104/forcelogout
	//strResponseJson = "";
	CString strHostHeader = GetHostHeaderStr(strUrl);

	::curl_easy_setopt(m_curl, CURLOPT_URL, strUrl);
	::curl_easy_setopt(m_curl, CURLOPT_CUSTOMREQUEST, "DELETE");
	::curl_easy_setopt(m_curl, CURLOPT_WRITEFUNCTION, PutWriteFunCallBack);
	::curl_easy_setopt(m_curl, CURLOPT_WRITEDATA, cRev);
	::curl_easy_setopt( m_curl, CURLOPT_TIMEOUT, m_iTimeOut);

	struct curl_slist *headers = NULL;
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTTYPE);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPTLANGUAGE);
	headers = curl_slist_append(headers, strHostHeader);
	headers = curl_slist_append(headers, HTTPHEADER_ACCEPT);
	headers = curl_slist_append(headers, HTTPHEADER_TRANSFERENCODING);
	headers = curl_slist_append(headers, HTTPHEADER_CONTENTLENGTH0);
	headers = curl_slist_append(headers, HTTPHEADER_EXPECT);
	::curl_easy_setopt(m_curl, CURLOPT_HTTPHEADER, headers);

	CURLcode ret = curl_easy_perform(m_curl);

	::curl_easy_cleanup(m_curl);

	if(0 == strlen(cRev))
	{
		strRet = ERROR_LIBCURL;
	}
	else
	{
		strRet = GetJson(cRev);
	}

	return strRet;
}

下载

//=======================================================
// 函 数 名：GetEmailAttach
// 功能描述：获取邮件附件
// 输入参数：cFileID:	文件ID
// 输出参数：
// 返回参数：
// 创建日期：2012.06.28
// 修改日期：2012.08.03
// 作    者：
// 附加说明：
//========================================================
int CDispatch::GetEmailAttach(char* cFileID, char* cFileName)
{
	//参数校验
	if (NULL == cFileID || strlen(cFileID) <= 0 || strlen(cFileID) > MAX_OCX_PARAM_LEN
		|| NULL == cFileName || strlen(cFileName) <= 0 || strlen(cFileName) > MAX_OCX_PARAM_LEN)
	{
		m_strLastError = "";
		m_strLastErrorMsg = "";
		return ERROR_PARAM_ERROR;
	}

	//未签入
	if (!m_bAgentLogin)
	{
		m_strLastError = "";
		m_strLastErrorMsg = "";
		return ERROR_NOT_SIGNIN;
	}

	BOOL bRet = FALSE;
	int nRet = ERROR_OK;

	//创建curl对象 
	CURL *curl; 
	CURLcode res; 

	struct HttpFile httpFile = 
	{ 
		cFileName,
		NULL 
	};

	curl_global_init(CURL_GLOBAL_DEFAULT); 
	//curl初始化 
	curl = curl_easy_init(); 

	//curl对象存在的情况下执行操作 
	if (curl) 
	{ 
		//拼接地址
		CString strURL;
		strURL.Format(AGENT_REST_GETEMAILATTACH_URL, m_strAgentID);
		strURL = m_strUrl + strURL + CString(cFileID);

		//设置远端地址 
		curl_easy_setopt(curl, CURLOPT_URL, strURL);
		//执行写入文件流操作 
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite); 
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, &httpFile); 

		//写入文件 
		res = curl_easy_perform(curl); 
		//释放curl对象 
		curl_easy_cleanup(curl); 

		if (CURLE_OK != res)
		{
			nRet = ERROR_HTTP_FAIL;
		} 
	} 
	if (httpFile.stream) 
	{ 
		//关闭文件流 
		fclose(httpFile.stream); 
	} 
	//释放curl对象 
	curl_global_cleanup(); 

	return nRet;
}

回调函数：

//=======================================================
// 函 数 名：my_fwrite
// 功能描述：回调函数，用于下载文件
// 输入参数：cURL: Agent服务器IP
//           cService: Agent服务工程名
// 输出参数：
// 返回参数：
// 创建日期：
// 修改日期：
// 作    者:
// 附加说明：
//========================================================
int my_fwrite(void *buffer, size_t size, size_t nmemb, void *stream) 
{ 
	struct HttpFile *out=(struct HttpFile *)stream; 
	if (out && !out->stream) 
	{ 
		out->stream = fopen(out->filename, "wb"); 
		if (!out->stream) 
		{ 
			return -1; 
		} 
	} 
	return fwrite(buffer, size, nmemb, out->stream); 
} 

发送

//=======================================================
// 函 数 名：SendEmailAttach
// 功能描述：座席在收到邮件类型的文字交谈后，调用下面的接口可以实现对邮件的回复。  
// 输入参数：cCallID:			//文字交谈的会话ID
//			 cFileName			//磁盘完整路径
// 输出参数：
// 返回参数：
// 创建日期：
// 修改日期：
// 作    者：
// 附加说明：
//========================================================
int CDispatch::SendEmailAttach(char* cCallID, char* cFileName)
{
	//参数校验
	if (NULL == cCallID || strlen(cCallID) <= 0 || strlen(cCallID) > MAX_OCX_PARAM_LEN
		|| NULL == cFileName || strlen(cFileName) <= 0 || strlen(cFileName) > MAX_OCX_PARAM_LEN)
	{
		m_strLastError = "";
		m_strLastErrorMsg = "";
		return ERROR_PARAM_ERROR;
	}

	//未签入
	if (!m_bAgentLogin)
	{
		m_strLastError = "";
		m_strLastErrorMsg = "";
		return ERROR_NOT_SIGNIN;
	}

	int nRet = ERROR_OK;

	//Rest请求的返回值
	char cRecvMsg[MAX_REST_REQUEST_LEN + 1];
	memset(cRecvMsg, 0, MAX_REST_REQUEST_LEN + 1);

	//创建curl对象 
	CURL *curl; 
	CURLcode res; 

	curl_global_init(CURL_GLOBAL_WIN32); 
	//curl初始化 
	curl = curl_easy_init(); 

	//curl对象存在的情况下执行操作 
	if (curl) 
	{ 
		//拼接地址
		CString strURL;
		strURL.Format(AGENT_REST_SENDEMAILATTACH_URL, m_strAgentID);
		strURL = m_strUrl + strURL + CString(cCallID);

		//设置远端地址 
		curl_easy_setopt(curl, CURLOPT_URL, strURL);
		curl_httppost *post = NULL;	
		curl_httppost *last = NULL;	

		// 文本数据
		curl_formadd(&post, &last, CURLFORM_COPYNAME, "name", CURLFORM_COPYCONTENTS, "JGood", CURLFORM_END);
		curl_formadd(&post, &last, CURLFORM_COPYNAME, "address", CURLFORM_COPYCONTENTS, "HangZhou", CURLFORM_END);
		// 文本文件中的数据
		curl_formadd(&post, &last, CURLFORM_COPYNAME, "file", CURLFORM_FILECONTENT, "D:\\Sunset.jpg", CURLFORM_END);
		curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, GetRetMessage); 
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, cRecvMsg); 

		
		//curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, head_data);

		//curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY);
	/*	char szRetcode[MAX_RET_PARAM_LEN];
		memset(szRetcode, 0, MAX_RET_PARAM_LEN);
		size_t size;
		CURLcode rtcode = curl_easy_recv(curl, szRetcode, MAX_RET_PARAM_LEN, &size);
		if (CURLE_AGAIN  == rtcode)
		{
			int i;
			i = 1;
		}*/

		//写入文件 
		res = curl_easy_perform(curl); 
		curl_formfree(post);

		//CURLcode rtcode = curl_easy_recv( CURL * curl , void * buffer , size_t buflen , size_t * n );
	


		if (CURLE_OK != res)
		{
			nRet = ERROR_HTTP_FAIL;
		}

	} 

	//释放curl对象 
	curl_global_cleanup(); 

	return nRet;
}

回调函数：

//文件写入流 
int GetRetMessage(void *buffer, size_t size, size_t nmemb, void *stream) 
{ 
	char *msg=(char *)stream; 
	
	strcat(msg,(char*)buffer);

	return 0;
}