本文參考：封裝利用libwebsockets寫出的客戶端、服務端程序為客戶端服務端類_逍遙游的博客-CSDN博客_libwebsockets封裝

最近項目需要使用C++連接websocket服務器，選擇了純C實現的libwebsockets庫；

libwebsockets下載地址：GitHub - warmcat/libwebsockets: canonical libwebsockets.org networking library

添加的openssl是openssl-1.1.1f

編譯：

cmake .. -DLWS_WITH_HTTP2=1 -DLWS_OPENSSL_INCLUDE_DIRS=../../openssl-1.1.1f/include -DLWS_OPENSSL_LIBRARIES="../../openssl-1.1.1f/libssl.a;../../openssl-1.1.1f/libcrypto.a" -DLWS_WITH_LIBEV=1 -DLIBEV_INCLUDE_DIRS=../../libev -DLIBEV_LIBRARIES=../../libev/.libs/libev.a

常用的cmake參數：

• -DLWS_WITH_STATIC=1：編譯靜態庫
• -DLWS_WITH_SHARED=1：編譯動態庫
• -DLWS_WITH_SSL=1：添加openssl
• -DLWS_WITH_HTTP2=1：添加http
• -DLWS_OPENSSL_INCLUDE_DIRS=：添加openssl的頭文件目錄
• -DLWS_OPENSSL_LIBRARIES=：添加openssl的庫（動態庫靜態庫均可）
• -DLWS_WITH_LIBEV=1：添加libev
• -DLIBEV_INCLUDE_DIRS=：添加libev的頭文件目錄
• -DLIBEV_LIBRARIES=：添加libev的庫（動態庫靜態庫均可）

注：

• 以上參數若不想再cmake時攜帶，也可以直接修改?CMakeLists.txt對用參數
• 建議可以自己實現IO復用，使用lws_get_socket_fd()獲取fd，自己實現epoll進行監聽，也可以直接使用libwebsockets自帶的poll

目前只實現了client封裝類：

client.h

#ifndef _CLIENT #define _CLIENT#include <iostream> #include <fstream> #include <stack> #include <queue> #include <signal.h> #include <pthread.h> #include "json/json.h" #include "libwebsockets.h"using namespace std;#define MAX_PAYLOAD_SIZE 8 * 1024 typedef enum {CLIENT_IDLE,CLIENT_CONNECTING,CLIENT_CONNECTED,CLIENT_AWAITING_SEND,ClIENT_COMPLETE_RECV,CLIENT_CLOSED }TSTAT;typedef struct session_data {int msg_count;unsigned char buf[LWS_PRE + MAX_PAYLOAD_SIZE];int len; }session_data, *SESSIONDATA;class CWSClient:public CLog {public:CWSClient(string url);~CWSClient();void init();int set_ssl(const char* ca_filepath,const char* server_cert_filepath,const char*server_private_key_filepath,int ssl_conn);bool create();bool connect(int ssl_conn);bool run(int wait_time);int send(string data);int recv(string data);int getRecvSize();string getRecvMsg();void popRecvMsg();void setLogLevel(int level);TSTAT getConnStat();void destroy();void setEnd(bool flag);friend void* WSpthreadFunc(void* arg);friend int callback( struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len );private:string m_cacheFile;bool m_end;int m_waittime;pthread_t m_threadID;queue<string> m_sendMsgQueue;queue<string> m_recvMsgQueue;SESSIONDATA m_session_data;string m_url;const char* m_prot;const char* m_ads;const char* m_path;int m_port;TSTAT m_stat;int m_logLevel;struct lws_protocols * m_protocols;struct lws_context_creation_info m_ctx_info; /* 用于創建vhost或者context的參數 */struct lws_context * m_context;struct lws_client_connect_info m_conn_info;struct lws * m_wsi;pthread_mutex_t m_rmutex; pthread_mutex_t m_smutex; };#endif

client.cpp

#include "websocketclient.h" static void emit_log(int level, const char *line) {/*自己實現日子打印回調，如將對應日志寫入文件，如果此回調置為NULL的話，則日志默認打印到stderr*/ } void* WSpthreadFunc(void* arg);int callback( struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len ) {CWSClient *wsclient = NULL;const struct lws_protocols* protocols = lws_get_protocol(wsi);if(protocols && protocols[0].user)wsclient = (CWSClient *) protocols[0].user;switch ( reason ){case LWS_CALLBACK_PROTOCOL_INIT:{lwsl_notice("Protocol init\n");}break;case LWS_CALLBACK_CLIENT_ESTABLISHED: // 連接到服務器后的回調{lwsl_notice( "Connected to server ok!\n" );wsclient->m_stat = CLIENT_CONNECTED;}break;case LWS_CALLBACK_CLIENT_RECEIVE: // 接收到服務器數據后的回調，數據為in，其長度為len{lwsl_notice( "recv: %s\n", (char *) in );char *in_str = (char *) in; }break;case LWS_CALLBACK_CLIENT_WRITEABLE: // 當此客戶端可以發送數據時的回調if( !wsclient->m_sendMsgQueue.empty() ){lwsl_notice( "entry callback client write \n");pthread_mutex_lock(&wsclient->m_smutex);string tts_params = wsclient->m_sendMsgQueue.front(); memset( wsclient->m_session_data->buf, 0, sizeof( wsclient->m_session_data->buf ));char *msg = (char*)&wsclient->m_session_data->buf[ LWS_PRE ];wsclient->m_session_data->len = sprintf( msg, "%s", tts_params.c_str() );lwsl_notice( "send: %s\n", msg );/*LWS will buffer the remainder automatically, and send it out autonomously.*/lws_write( wsi, &wsclient->m_session_data->buf[ LWS_PRE ], wsclient->m_session_data->len, LWS_WRITE_TEXT );wsclient->m_session_data->msg_count++;wsclient->m_sendMsgQueue.pop();pthread_mutex_unlock(&wsclient->m_smutex);}break;case LWS_CALLBACK_CLIENT_CLOSED:{lwsl_notice( "ws_client is closed!\n" );wsclient->m_stat = CLIENT_CLOSED;}break;default:break;}return 0; }CWSClient::CWSClient(string url) {m_url = url;m_context = NULL;m_wsi = NULL;m_stat = CLIENT_IDLE;m_end = false; //結束標志memset(&m_ctx_info,0x00,sizeof(m_ctx_info));memset(&m_conn_info,0x00,sizeof(m_conn_info));pthread_mutex_init(&m_smutex, NULL);pthread_mutex_init(&m_rmutex, NULL); }CWSClient::~CWSClient() {pthread_mutex_destroy( &m_smutex );pthread_mutex_destroy( &m_rmutex );lws_context_destroy( m_context );if (m_session_data)delete(m_session_data);if(m_protocols)delete(m_protocols);m_end = true; }void CWSClient::init() {m_protocols = new (struct lws_protocols[2]); //該列表以具有空回調指針的條目結束m_ctx_info.port = CONTEXT_PORT_NO_LISTEN;m_ctx_info.iface = NULL;m_ctx_info.protocols = m_protocols;m_ctx_info.gid = -1;m_ctx_info.uid = -1;m_protocols[0].name = "wss";m_protocols[0].callback = &callback;m_protocols[0].per_session_data_size = 0;m_protocols[0].rx_buffer_size = 0;m_protocols[0].id = 0;m_protocols[0].user = this;m_protocols[1].name = NULL;m_protocols[1].callback = NULL;m_protocols[1].per_session_data_size = 0;m_session_data = new session_data;}/**client一般不使用證書，直接置為NULL就可以**/ int CWSClient::set_ssl(const char* ca_filepath,const char* server_cert_filepath,const char*server_private_key_filepath,int ssl_conn) {m_ctx_info.ssl_ca_filepath = ca_filepath;m_ctx_info.ssl_cert_filepath = server_cert_filepath;m_ctx_info.ssl_private_key_filepath = server_private_key_filepath;if(ssl_conn == LCCSCF_USE_SSL || ssl_conn == (LCCSCF_USE_SSL|LCCSCF_ALLOW_INSECURE))m_ctx_info.options |= LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;return ssl_conn; }bool CWSClient::create() {/**創建一個WebSocket處理器**/m_context = lws_create_context( &m_ctx_info );if(!m_context){lwsl_err("%s: lws_create_context error \n", __func__);return false;}return true; }bool CWSClient::connect(int ssl_conn) {char tmp_url[1024] = {0};strncpy(tmp_url,m_url.c_str(),sizeof(tmp_url)-1); //lws_parse_uri解析之后會改變原url,不能使用string = ，淺拷貝if (lws_parse_uri(tmp_url, &m_prot, &m_ads, &m_port, &m_path))lwsl_err("%s: uri error %s\n", __func__, m_url.c_str());m_conn_info.context = m_context;m_conn_info.address = m_ads;m_conn_info.port = m_port;m_conn_info.ssl_connection = ssl_conn;m_conn_info.path = (char*)m_url.c_str();m_conn_info.host = m_ads;m_conn_info.sys_tls_client_cert = 0;m_conn_info.protocol = m_protocols[0].name;// 下面的調用觸發LWS_CALLBACK_PROTOCOL_INIT事件// 創建一個客戶端連接m_stat = CLIENT_CONNECTING;m_wsi = lws_client_connect_via_info( &m_conn_info );if(!m_wsi){lwsl_err("%s: lws_client_connect_via_info error \n", __func__);return false;}return true; }bool CWSClient::run(int wait_time) {m_waittime = wait_time;pthread_attr_t attr;pthread_attr_init(&attr);pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED);pthread_attr_setstacksize(&attr, 512*1024);if(pthread_create(&m_threadID, &attr, WSpthreadFunc, this) != 0){ lwsl_err("[CWSClient] Failed with pthread_create: %s\n", strerror(errno));return false;} elselwsl_notice("[CWSClient] Successed with pthread_create\n");return true; }int CWSClient::send(string data) {pthread_mutex_lock(&m_smutex);m_sendMsgQueue.push(data);pthread_mutex_unlock(&m_smutex);return (int)data.length(); }int CWSClient::recv(string data) {pthread_mutex_lock(&m_rmutex);m_recvMsgQueue.push(data);pthread_mutex_unlock(&m_rmutex);return (int)data.length(); }int CWSClient::getRecvSize() {return m_recvMsgQueue.size(); }string CWSClient::getRecvMsg() {string data;pthread_mutex_lock(&m_rmutex);if( !m_recvMsgQueue.empty() )data = m_recvMsgQueue.front();pthread_mutex_unlock(&m_rmutex);return data; }void CWSClient::popRecvMsg() {pthread_mutex_lock(&m_rmutex);if( !m_recvMsgQueue.empty() )m_recvMsgQueue.pop();pthread_mutex_unlock(&m_rmutex); }void CWSClient::setLogLevel(int level) {/*第二個參數置為NULL ,打印到stderr*/lws_set_log_level(level, emit_log); }TSTAT CWSClient::getConnStat() {return m_stat; }void CWSClient::destroy() {pthread_mutex_destroy( &m_smutex );lws_context_destroy( m_context );if(m_session_data){delete(m_session_data);m_session_data = NULL;}if(m_protocols){delete[] m_protocols;m_protocols = NULL;}m_end = true; }void CWSClient::setEnd(bool flag) {m_end = flag;lwsl_notice("WSpthreadFunc end = %d\n",flag); }void* WSpthreadFunc(void* arg) {CWSClient* wsClient = (CWSClient*)arg;if(!wsClient){lwsl_err("WSpthreadFunc is NULL\n");return NULL;}while(1){if(wsClient == NULL || wsClient->m_end){lwsl_notice("WSpthreadFunc exit\n");break;}lws_service( wsClient->m_context, wsClient->m_waittime );/***下面的調用的意義是：當連接可以接受新數據時，觸發一次WRITEABLE事件回調*當連接正在后臺發送數據時，它不能接受新的數據寫入請求，所有WRITEABLE事件回調不會執行**/if(!wsClient->m_sendMsgQueue.empty()){lws_callback_on_writable( wsClient->m_wsi );wsClient->m_stat = CLIENT_AWAITING_SEND;}}wsClient->m_threadID = 0;return NULL; }

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