深入理解WebSocket接口：如何使用C++实现行情接口

在现代网络应用中，实时数据传输变得越来越重要。通过WebSocket，我们可以建立一个持久连接，让服务器和客户端之间进行双向通信。这种技术不仅可以提供更快的响应速度，还可以减少不必要的网络流量。本文将详细介绍如何使用C++来实现WebSocket行情接口。

WebSocket简介

WebSocket是一种在单个TCP连接上提供全双工通信通道的协议。它最初是为浏览器和服务器之间的实时通信而开发的，但现在已经被广泛应用于各种网络编程中。

C++中的WebSocket实现

下面是一个使用C++实现WebSocket行情接口的基本示例：

#include <websocketpp/config/asio_no_tls_client.hpp>
#include <websocketpp/client.hpp>
#include <string>
#include <iostream>
#include <memory>
#include <assert.h>
#include <cstring>
#include "zlib.h"
#define CHUNK 16384
using websocketpp::lib::placeholders::_1;
using websocketpp::lib::placeholders::_2;
using websocketpp::lib::bind;
typedef websocketpp::client <websocketpp::config::asio_client> client;
typedef websocketpp::config::asio_client::message_type::ptr message_ptr;
int DecompressString(const char *in_str, size_t in_len, std::string &out_str);/*** 接收处理*/
void on_message(client *c, websocketpp::connection_hdl hdl, message_ptr msg) {//文本消息if (msg->get_opcode()==websocketpp::frame::opcode::text){std::cout <<"Text响应:"<<msg->get_payload().c_str()<< std::endl;}//二进制消息if (msg->get_opcode()==websocketpp::frame::opcode::binary){std::string tmp = "";std::string &out_decompress = tmp;DecompressString( msg->get_payload().c_str(), msg->get_payload().size(), out_decompress);std::cout <<"Binary响应:"<<out_decompress<< std::endl;}
}/*** 连接处理*/
void on_open(client *c, websocketpp::connection_hdl hdl) {//发送订阅指令c->send(hdl, "add=lv1_600519,lv2_600519", websocketpp::frame::opcode::text);std::cout << "连接成功" << std::endl;
}int main(int argc, char *argv[]) {//服务地址。 注意:C++版本的地址 问号前需加斜杠std::string wsUrl = "ws://<服务器地址>/?token=<jvQuant token>";client c;//连接相关try {//debug日志开关
//        c.set_access_channels(websocketpp::log::alevel::all);c.clear_access_channels(websocketpp::log::alevel::all);c.init_asio();// 注册处理函数c.set_message_handler(bind(&on_message, &c, ::_1, ::_2));c.set_open_handler(bind(&on_open, &c, _1));websocketpp::lib::error_code ec;client::connection_ptr con = c.get_connection(wsUrl, ec);if (ec) {std::cout << "连接失败: " << ec.message() << std::endl;return 0;}c.connect(con);c.run();} catch (websocketpp::exception const &e) {std::cout << e.what() << std::endl;}
}
/***解压缩方法*/
int DecompressString(const char *in_str, size_t in_len, std::string &out_str) {if (!in_str)return Z_DATA_ERROR;int ret;unsigned have;z_stream strm;unsigned char out[CHUNK];strm.zalloc = Z_NULL;strm.zfree = Z_NULL;strm.opaque = Z_NULL;strm.avail_in = 0;strm.next_in = Z_NULL;ret = inflateInit2(&strm, -MAX_WBITS);if (ret != Z_OK)return ret;std::shared_ptr <z_stream> sp_strm(&strm, [](z_stream *strm) {(void) inflateEnd(strm);});const char *end = in_str + in_len;size_t pos_index = 0;size_t distance = 0;int flush = 0;do {distance = end - in_str;strm.avail_in = (distance >= CHUNK) ? CHUNK : distance;strm.next_in = (Bytef *) in_str;in_str += strm.avail_in;flush = (in_str == end) ? Z_FINISH : Z_NO_FLUSH;do {strm.avail_out = CHUNK;strm.next_out = out;ret = inflate(&strm, Z_NO_FLUSH);if (ret == Z_STREAM_ERROR)break;switch (ret) {case Z_NEED_DICT:ret = Z_DATA_ERROR;case Z_DATA_ERROR:case Z_MEM_ERROR:return ret;}have = CHUNK - strm.avail_out;out_str.append((const char *) out, have);} while (strm.avail_out == 0);} while (flush != Z_FINISH);return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}