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libwebsockets
websocket客户端基本流程网上都有，我只额外优化了重连机制。
在服务器异常断开时不触发LWS_CALLBACK_CLOSED或LWS_CALLBACK_CLIENT_CONNECTION_ERROR，导致无法自动重连
通过定时检查链接是否可写入判断链接是否有效

 // 判断wsi是否可用if ((std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count() -last_time) > detect_dup){if (lws_callback_on_writable(wsi) <= 0){std::cerr<< "[WebSocket] Connection failed, retrying in 3s..." << std::endl;wsi = nullptr;// continue;}last_time = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();}

完整代码

#ifndef MYWSCLIENT_H
#define MYWSCLIENT_H#pragma once#include <iostream>
#include <thread>#include <libwebsockets.h>
#include <atomic>
#include <functional>
#include <mutex>
#include <condition_variable>/*
异步启动WebSocket
自动重连
*/
class MyWSClient
{
public:using MessageCallback = std::function<void(const std::string &)>;MyWSClient(const std::string &url, int port, const std::string &path, MessageCallback onMessage = nullptr);~MyWSClient();void start();void stop();void sendMessage(const std::string &message);private:std::string url;std::string path;int port;int detect_dup = 3; // sMessageCallback onMessageCallback;struct lws_context *context;struct lws *wsi;std::thread wsThread;std::atomic<bool> running;std::mutex sendMutex;std::vector<std::string> sendQueue;void run();void reconnect();static int callback(struct lws *wsi, enum lws_callback_reasons reason,void *user, void *in, size_t len);static struct lws_protocols protocols[];
};#endif

#include "MyWSClient.h"#include "spdlog/spdlog.h"using namespace std;MyWSClient::MyWSClient(const std::string &url, int port, const std::string &path, MessageCallback onMessage): url(url), port(port), path(path), onMessageCallback(onMessage), context(nullptr), wsi(nullptr), running(false) {}MyWSClient::~MyWSClient() { stop(); }void MyWSClient::start()
{running = true;wsThread = std::thread(&MyWSClient::run, this);
}void MyWSClient::stop()
{running = false;if (context){lws_context_destroy(context);context = nullptr;}if (wsThread.joinable()){wsThread.join();}
}void MyWSClient::sendMessage(const string &message)
{if (!wsi){std::cout << __func__ << " error send, ws server not connected" << std::endl;return;}std::lock_guard<std::mutex> lock(sendMutex);sendQueue.push_back(message);if (wsi){int res = lws_callback_on_writable(wsi);std::cout << __func__ << " send :" << message << ", res:" << res << std::endl;}
}
void MyWSClient::run()
{struct lws_context_creation_info ctx_info = {};struct lws_client_connect_info conn_info = {};ctx_info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;ctx_info.port = CONTEXT_PORT_NO_LISTEN;ctx_info.protocols = protocols;context = lws_create_context(&ctx_info);if (!context){std::cerr << "[WebSocket] Failed to create context" << std::endl;return;}conn_info.context = context;conn_info.address = url.c_str();conn_info.port = port;conn_info.path = path.c_str();conn_info.host = url.c_str();conn_info.origin = url.c_str();conn_info.protocol = "ws";conn_info.ssl_connection = LCCSCF_USE_SSL |LCCSCF_ALLOW_SELFSIGNED |LCCSCF_SKIP_SERVER_CERT_HOSTNAME_CHECK |LCCSCF_ALLOW_EXPIRED;conn_info.userdata = this;long last_time = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();while (running){if (!wsi){std::this_thread::sleep_for(std::chrono::seconds(3));std::cout << "[WebSocket] Attempting to connect..." << std::endl;wsi = lws_client_connect_via_info(&conn_info);}// 判断wsi是否可用if ((std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count() -last_time) > detect_dup){if (lws_callback_on_writable(wsi) <= 0){std::cerr<< "[WebSocket] Connection failed, retrying in 3s..." << std::endl;wsi = nullptr;// continue;}last_time = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();}if (lws_service(context, 0) < 0){std::cerr<< "[WebSocket] lws_service failed" << std::endl;}}lws_context_destroy(context);
}void MyWSClient::reconnect()
{stop();std::cerr<< "[WebSocket] reconnect, retrying in 3s..." << std::endl;run();
}int MyWSClient::callback(lws *wsi, lws_callback_reasons reason, void *user, void *in, size_t len)
{MyWSClient *client = (MyWSClient *)lws_wsi_user(wsi);switch (reason){case LWS_CALLBACK_CLIENT_ESTABLISHED:{std::cout << "[WebSocket] Connected to server" << std::endl;lws_callback_on_writable(wsi); // 请求写入break;}case LWS_CALLBACK_CLIENT_RECEIVE:{if (client->onMessageCallback){client->onMessageCallback(std::string((char *)in, len));}break;}case LWS_CALLBACK_CLIENT_WRITEABLE:{std::lock_guard<std::mutex> lock(client->sendMutex);if (!client->sendQueue.empty()){std::string message = client->sendQueue.front();client->sendQueue.erase(client->sendQueue.begin());std::cout << __func__ << " send:" << message << std::endl;// 确保 LWS_PRE 字节已预留unsigned char buf[LWS_PRE + 1024] = {0};int msgLen = message.size();memcpy(buf + LWS_PRE, message.c_str(), msgLen);int sent = lws_write(wsi, buf + LWS_PRE, msgLen, LWS_WRITE_TEXT);if (sent < 0){std::cerr << __func__ << "lws_write failed!" << std::endl;}// 如果还有数据，继续请求写入if (!client->sendQueue.empty()){lws_callback_on_writable(wsi);}}break;}case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:{std::cerr << "[WebSocket] Connection error: " << (in ? (char *)in : "unknown") << std::endl;client->wsi = nullptr;// client->reconnect();break;}case LWS_CALLBACK_CLOSED:{std::cout << "[WebSocket] Connection closed" << std::endl;client->wsi = nullptr;// client->reconnect();break;}default:break;}return 0;
}// 定义协议数组
struct lws_protocols MyWSClient::protocols[] = {{"ws", MyWSClient::callback, 0, 4096},{nullptr, nullptr, 0, 0}};