基于libcurl实现REST风格http/https的get和post

c/c++开发中经常要用到http/https协议，直接使用socket工作量很大，要是使用socket实现https，那更不可思议，开源的c/c++的http客户端框架，libcurl是首选，而且也相当成熟稳定，最近C++项目中用到https请求，就做下研究。

libcurl简介(来源官网)

libcurl是一个跨平台的网络协议库，支持http, https, ftp, gopher, telnet, dict, file, 和ldap 协议。libcurl同样支持HTTPS证书授权，HTTP POST, HTTP PUT, FTP 上传, HTTP基本表单上传，代理，cookies,和用户认证。官网地址：https://curl.haxx.se/libcurl/

实现HTTP/GET：

Get.cpp

/********************************************************
Copyright (C),  2016-2018,
FileName:		Get
Author:        	woniu201
Email:         	wangpengfei.201@163.com
Created:       	2018/10/15
Description:	实现HTTP/HTTPS GET请求
********************************************************/
#include "main.h"

size_t WriteGetResp(void *buffer, size_t size, size_t nmemb, void *userp)
{
	((string*)userp)->append((char*)buffer, 0, size*nmemb);
	return size*nmemb;
}

/************************************
@ Brief:		GET请求
@ Author:		woniu201 
@ Created:		2018/10/15
@ Return:            
************************************/
int HttpGet(char* url)
{
	string respData;
	CURL* curl;
	CURLcode res;

	curl = curl_easy_init();
	if (curl == NULL)
	{
		return 1;
	}

	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteGetResp);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &respData);

//  	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS, 5000); //libcurl存在毫秒超时bug,如果设备小于1000ms立即返回失败
//  	curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS, 5000); //设置超时时间

	bool bCA = FALSE;
	if (!bCA)
	{
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE);//设定为不验证证书和HOST 
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, FALSE); 
	}
	else
	{
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, TRUE); 
		curl_easy_setopt(curl, CURLOPT_CAINFO, ""); 
	}

	res = curl_easy_perform(curl);
	if (res != CURLE_OK)
	{
		cout << curl_easy_strerror(res) << endl;
	}

	curl_easy_cleanup(curl);

	cout << Utf8ToAscii(respData) << endl;
	return 0;
}

实现HTTP/POST：

Post.cpp

/********************************************************
Copyright (C),  2016-2018,
FileName:		Post
Author:        	woniu201
Email:         	wangpengfei.201@163.com
Created:       	2018/10/15
Description:	实现HTTP/HTTPS POST请求
********************************************************/
#include "main.h"

size_t WritePostBodyResp(void *buffer, size_t size, size_t nmemb, void *userp)
{
	((string*)userp)->append((char*)buffer, 0, size*nmemb);
	return size*nmemb;
}

size_t WritePostHeaderResp(void *buffer, size_t size, size_t nmemb, void *userp)
{
	((string*)userp)->append((char*)buffer, 0, size*nmemb);
	return size*nmemb;
}

/************************************
@ Brief:		POST请求
@ Author:		woniu201 
@ Created:		2018/10/15
@ Return:            
************************************/
int HttpPost(char* url, char* body)
{
	string respBodyData;
	string respHeadData;
	CURL* curl;
	CURLcode res;

	//设置头
	struct curl_slist *headers = NULL;
	headers = curl_slist_append(headers, "Content-Type:application/json;charset=UTF-8");
	
	curl = curl_easy_init();
	if (curl == NULL)
	{
		return 1;
	}

	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, body);
	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

	curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, WritePostHeaderResp);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WritePostBodyResp);
	curl_easy_setopt(curl, CURLOPT_WRITEHEADER, &respHeadData);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &respBodyData);

	//  	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS, 5000); //libcurl存在毫秒超时bug,如果设备小于1000ms立即返回失败
	//  	curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS, 5000); //设置超时时间

	bool bCA = FALSE;
	if (!bCA)
	{
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE);//设定为不验证证书和HOST 
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, FALSE); 
	}
	else
	{
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, TRUE); 
		curl_easy_setopt(curl, CURLOPT_CAINFO, ""); 
	}

	res = curl_easy_perform(curl);
	if (res != CURLE_OK)
	{
		cout << curl_easy_strerror(res) << endl;
	}
	curl_slist_free_all(headers);
	curl_easy_cleanup(curl);

	cout << Utf8ToAscii(respHeadData) << endl;
	cout << Utf8ToAscii(respBodyData) << endl;

	return 0;
}

其他代码：

Utils.cpp

/********************************************************
Copyright (C),  2016-2018,
FileName:		utils
Author:        	woniu201
Email:         	wangpengfei.201@163.com
Created:       	2018/10/15
Description:	ASSIC--UTF8互转
********************************************************/
#include "main.h"
#include <string>
#include <Windows.h>
#include <wchar.h>
using namespace std;

wstring	AsciiToUnicode(const string& str) {  
	// 预算-缓冲区中宽字节的长度    
	int unicodeLen = MultiByteToWideChar(CP_ACP, 0, str.c_str(), -1, nullptr, 0);  
	// 给指向缓冲区的指针变量分配内存    
	wchar_t *pUnicode = (wchar_t*)malloc(sizeof(wchar_t)*unicodeLen);  
	// 开始向缓冲区转换字节    
	MultiByteToWideChar(CP_ACP, 0, str.c_str(), -1, pUnicode, unicodeLen);  
	wstring ret_str = pUnicode;  
	free(pUnicode);  
	return ret_str;  
}  
string UnicodeToAscii(const wstring& wstr) {  
	// 预算-缓冲区中多字节的长度    
	int ansiiLen = WideCharToMultiByte(CP_ACP, 0, wstr.c_str(), -1, nullptr, 0, nullptr, nullptr);  
	// 给指向缓冲区的指针变量分配内存    
	char *pAssii = (char*)malloc(sizeof(char)*ansiiLen);  
	// 开始向缓冲区转换字节    
	WideCharToMultiByte(CP_ACP, 0, wstr.c_str(), -1, pAssii, ansiiLen, nullptr, nullptr);  
	string ret_str = pAssii;  
	free(pAssii);  
	return ret_str;  
}

wstring Utf8ToUnicode(const string& str) {  
	// 预算-缓冲区中宽字节的长度    
	int unicodeLen = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, nullptr, 0);  
	// 给指向缓冲区的指针变量分配内存    
	wchar_t *pUnicode = (wchar_t*)malloc(sizeof(wchar_t)*unicodeLen);  
	// 开始向缓冲区转换字节    
	MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, pUnicode, unicodeLen);  
	wstring ret_str = pUnicode;  
	free(pUnicode);  
	return ret_str;  
}  
string UnicodeToUtf8(const wstring& wstr) {  
	// 预算-缓冲区中多字节的长度    
	int ansiiLen = WideCharToMultiByte(CP_UTF8, 0, wstr.c_str(), -1, nullptr, 0, nullptr, nullptr);  
	// 给指向缓冲区的指针变量分配内存    
	char *pAssii = (char*)malloc(sizeof(char)*ansiiLen);  
	// 开始向缓冲区转换字节    
	WideCharToMultiByte(CP_UTF8, 0, wstr.c_str(), -1, pAssii, ansiiLen, nullptr, nullptr);  
	string ret_str = pAssii;  
	free(pAssii);  
	return ret_str;  
}  

/************************************
@ Brief:		ASSIC转UTF8
@ Author:		woniu201 
@ Created:		2018/10/16
@ Return:            
************************************/
string AsciiToUtf8(const string& str) {  
	return UnicodeToUtf8(AsciiToUnicode(str));  
}  

/************************************
@ Brief:		UTF8转ASSIC
@ Author:		woniu201 
@ Created:		2018/10/16
@ Return:            
************************************/
string Utf8ToAscii(const string& str) {  
	return UnicodeToAscii(Utf8ToUnicode(str));  
}  

 main.h

#ifndef _MAIN_H
#define _MAIN_H

#include <iostream>
#include <string>
#include "include/curl.h"

using namespace std;


#pragma comment(lib, "ssleay32.lib")
#pragma comment(lib, "libcurl.lib")

string AsciiToUtf8(const string& str);
string Utf8ToAscii(const string& str);

int HttpGet(char* url);
int HttpPost(char* url, char* body);
int HttpDownload(char* url,  char* filePath);
#endif

对应libcurl库和头文件下载地址(支持HTTPS)：点击下载

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