监听websocket channel

(() => {
    // 默认渠道名，可以根据需要修改
    const channel = 'siyuan-runjs';

    // 创建socket客户端
    createSocketClient(channel);

    // 当收到消息时被调用
    function onReceivedMessage(event) {
        let request = parseJson(event.data);
        let result = '';
        try {
            result = (new Function(request.code))();
        } catch (e) {
            result = e.message || '';
            console.error(e);
        }
        if(request.fromChannel) {
            postMessage(request.fromChannel, result);
        }
    }

    // 创建socket客户端
    function createSocketClient(channel) {
        // 连接 WebSocket 服务器
        const socket = new WebSocket('ws://'+location.host+'/ws/broadcast?channel='+channel);
  
        socket.onopen = function(e) {
            console.log('Channel '+channel+' connectioned!');
        };
  
        socket.onmessage = onReceivedMessage;
  
        socket.onclose = function(event) {
            console.log('Channel '+channel+' closed!');
        };
  
        socket.onerror = function(error) {
            console.error('WebSocket Error:', error);
        };

        return socket;
    }

    // 客户端向服务器发送消息
    function sendMessage(socket, message) {
        if (socket.readyState === WebSocket.OPEN) {
            socket.send(message);
        } else {
            console.error('WebSocket connection is not open');
        }
    }

    // 服务器向客户端发消息
    async function postMessage(channel, message) {
        const result = await fetchSyncPost('/api/broadcast/postMessage', {
            channel: channel,
            message: message
        });
        if(result.code !== 0 || !result.data) {
            console.error('postMessage error', result);
        }
    }

    // 解析json
    function parseJson(jsonString) {
        let json = {};
        try {
            json = JSON.parse(jsonString || '{}');
        } catch(e) {
            json = {};
            console.error('parseJson error', e);
        }
        return json;
    }
  
    // 发送api请求
    async function fetchSyncPost(url, data, returnType = 'json') {
        const init = {
            method: "POST",
        };
        if (data) {
            if (data instanceof FormData) {
                init.body = data;
            } else {
                init.body = JSON.stringify(data);
            }
        }
        try {
            const res = await fetch(url, init);
            const res2 = returnType === 'json' ? await res.json() : await res.text();
            return res2;
        } catch(e) {
            console.log(e);
            return returnType === 'json' ? {code:e.code||1, msg: e.message||"", data: null} : "";
        }
    }
})()