C/C++使用Curl发起Http请求

一、概述

　　使用curl发起http的get和pos请求示例

二、代码示例

　　1.封装Httpurl.h

#include <stdio.h>
#include <iostream>
#include <string>
#include <string.h>
#include "json/json.h"
#include <fstream>
extern "C" {
#include <curl/curl.h>
}

class HttpCurl {
private:
    //创建一个Curl句柄
    CURL* curl;
    CURLcode res;
    std::string baseUrl;
public:
    HttpCurl();
    ~HttpCurl();
public:
    void init();
    void setBaseUrl(std::string baseUrl);
    void get(std::string url);
    //void get();
    void post(std::string url,std::string bodyJson);
    //void post();
    void destory();
};

　　2.HttpCurl.cpp

#include "m_curl.h"

HttpCurl::HttpCurl() {
    //init();
}

HttpCurl::~HttpCurl() {

}
void HttpCurl::init() {
    //初始化curl库
    curl_global_init(CURL_GLOBAL_ALL);
}

void HttpCurl::setBaseUrl(std::string baseUrl) {
    this->baseUrl = baseUrl;
}

size_t write_callback(void* ptr, size_t size, size_t nmemb, void* stream)
{
    //在注释的里面可以打印请求流，cookie的信息
    //cout << "----->reply" << endl;
    std::string* str = (std::string*)stream;
    std::cout << *str << std::endl;
    (*str).append((char*)ptr, size * nmemb);
    std::cout << "callback is ......" << *str << std::endl;
    return size * nmemb;
}
//get请求
void HttpCurl::get(std::string url) {
    std::string httpUrl = this->baseUrl.append(url);
    std::cout << "请求接口=" << httpUrl << std::endl;
    //初始化curl句柄
    curl = curl_easy_init();
    //给句柄设置参数（封装一个http请求）
    curl_easy_setopt(curl, CURLOPT_URL, httpUrl.c_str());
    //设置http请求内容类型为json格式
    curl_slist* plist = curl_slist_append(NULL, "Content-Type:application/json;charset=UTF-8");
    //设置token
    curl_slist_append(plist, "Authorization:Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE3MjExMTg3MDYsInVzZXJuYW1lIjoiMTY5MTYzMTk0OTQyMyJ9.t8_e-kRYlmySUytIAj3Vp93YUoDBoXNzfd28dq2koQ0");
    //设置businessid
    curl_slist_append(plist, "businessId:1794906728071634946");
    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, plist);
    //给当前句柄设置一个从服务器返回数据的回调
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
    //给回调函数设置一个形参
    std::string response;
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)&response);

    //提交请求，阻塞等待服务器返回
    res = curl_easy_perform(curl);
    if (res != CURLE_OK) {
        printf("curl easy perform error res = %d\n", res);
        std::cout << "请求发生了一场" << std::endl;
    }
    std::cout << "response:" << response << std::endl;
    //处理服务器返回的数据
    //清空、释放句柄内存空间
    curl_easy_cleanup(curl);

}

void HttpCurl::post(std::string url, std::string bodyJson) {
    std::string httpUrl = this->baseUrl.append(url);
    std::cout << "url:" << httpUrl << std::endl;
    //初始化curl句柄
    curl = curl_easy_init();
    //给句柄设置参数（封装一个http请求）
    curl_easy_setopt(curl, CURLOPT_URL, httpUrl.c_str());
    //设置http请求内容类型为json格式
    curl_slist* plist = curl_slist_append(NULL, "Content-Type:application/json;charset=UTF-8");
    ////设置token
    //curl_slist_append(plist, "Authorization:Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE3MjExMTg3MDYsInVzZXJuYW1lIjoiMTY5MTYzMTk0OTQyMyJ9.t8_e-kRYlmySUytIAj3Vp93YUoDBoXNzfd28dq2koQ0");
    ////设置businessid
    //curl_slist_append(plist, "businessId:1794906728071634946");
    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, plist);
    curl_easy_setopt(curl, CURLOPT_POST, 1L); // POST
    //std::cout <<"----=" << result << std::endl;
    //printf("--------------%s\n", postJson.toStyledString().c_str());
    /*std::ofstream ofs;
    ofs.open("C:/Users/DBF-DEV-103/Downloads/curl_json_text.txt",std::ios::out);
    ofs << result << std::endl;
    ofs.close();*/
    //jsoncpp
    //这里有点不正常，如果直接使用postJson.toStyledString().c_str()后台无法解析，如果先把值赋值给std::string此方法就能行得通
    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, bodyJson.c_str());
    curl_easy_setopt(curl, CURLOPT_ENCODING, "utf-8");

    //给当前句柄设置一个从服务器返回数据的回调
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
    //给回调函数设置一个形参
    std::string response;
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)&response);

    //提交请求，阻塞等待服务器返回
    res = curl_easy_perform(curl);
    if (res != CURLE_OK) {
        printf("curl easy perform error res = %d\n", res);
        std::cout << "请求发生了异常" << std::endl;
    }
    std::cout << "response:" << response << std::endl;
    //处理服务器返回的数据
    //清空、释放句柄内存空间
    curl_easy_cleanup(curl);
}

void HttpCurl::destory() {
    curl_global_cleanup();//清除curl，释放内存
}

　　3.使用HttpCurl发起get和post请求

SetConsoleOutputCP(CP_UTF8);  // 设置控制台输出为 UTF-8 编码
std::cout << "start" << std::endl;
HttpCurl httpCurl;
//测试get请求
/*std::string baseUrl = "http://192.168.100.201:8080/";
httpCurl.setBaseUrl(baseUrl);
httpCurl.get("api/get/userinfo");*/
//测试post请求
std::string baseUrl = "http://192.168.190.164:8080/";
httpCurl.setBaseUrl(baseUrl);
Json::Value postJson;
postJson["username"] = "admin";
postJson["password"] = "123456";
std::string result = postJson.toStyledString();
httpCurl.post("api/user/login", result);