畅游网络：构建C++网络爬虫的指南

#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
#include <pplx/pplxtasks.h>
#include <iostream>
#include <vector>
#include <thread>
#include <unordered_map>

// 爬虫代理配置
const utility::string_t PROXY_DOMAIN = U(代理服务器域名);
const int PROXY_PORT = 代理服务器端口;
const utility::string_t PROXY_USERNAME = U("用户名");
const utility::string_t PROXY_PASSWORD = U("密码");

// 知乎热点URL
const utility::string_t ZHIHU_TRENDING_URL = U("https://www.zhihu.com/api/v4/questions/trending_topics");

// 使用cpprestsdk的http_client配置代理并访问知乎热点
void fetch_zhihu_trending(const utility::string_t& proxy_domain, int proxy_port, const utility::string_t& proxy_username, const utility::string_t& proxy_password, std::unordered_map<utility::string_t, int>& hot_topics) {
    web::http::client::http_client_config client_config;
    client_config.set_proxy(web::http::client::web_proxy(proxy_domain + U(":") + std::to_string(proxy_port)));
    client_config.set_credentials(web::http::credentials(proxy_username, proxy_password));

    web::http::client::http_client client(ZHIHU_TRENDING_URL, client_config);

    // 发送GET请求
    client.request(web::http::methods::GET).then([&hot_topics](web::http::http_response response) {
        return response.extract_json();
    }).then([&hot_topics](web::json::value json_response) {
        // 处理热点数据
        auto topics = json_response[U("data")].as_array();
        for (const auto& topic : topics) {
            utility::string_t name = topic[U("name")].as_string();
            int followers = topic[U("followers")].as_integer();
            hot_topics[name] += followers;
        }
    }).wait();
}

// 多线程抓取知乎热点
void multi_thread_fetch() {
    std::unordered_map<utility::string_t, int> hot_topics; // 存储热点数据

    std::vector<std::thread> threads;
    for (int i = 0; i < 5; ++i) { // 创建5个线程
        threads.push_back(std::thread(fetch_zhihu_trending, PROXY_DOMAIN, PROXY_PORT, PROXY_USERNAME, PROXY_PASSWORD, std::ref(hot_topics)));
    }

    for (auto& th : threads) { // 等待所有线程完成
        th.join();
    }

    // 输出热点数据
    for (const auto& pair : hot_topics) {
        std::wcout << pair.first << U(": ") << pair.second << std::endl;
    }
}

int main() {
    multi_thread_fetch();
    return 0;
}