Lets one remote control a shell via webrtc using https://github.com/tarasglek/webrtc-client

webrtc.ts

class RTC {
    pc;
    dc;
    _onMessage_cb = null;
    _onConnected_cb = null;
    constructor() {
        this.pc = null;
        this.dc = null;
    }
    onMessage(msg) {
        if (this._onMessage_cb) {
            this._onMessage_cb(msg);
        }
        this._onMessage_cb = null;
    }
    get connected() {
        return this.pc && this.pc.connectionState == "connected";
    }
    async connectAndcreateOffer() {
        const config = {
            iceServers: [
                {
                    urls: "stun:stun.1.google.com:19302",
                },
            ],
        };
        this.pc = new RTCPeerConnection(config);
        this.dc = this.pc.createDataChannel("chat", {
            negotiated: true,
            id: 0,
        });
        const dc = this.dc;
        const pc = this.pc;
        let self = this;
        // pc.oniceconnectionstatechange = (ev) => handleChange(pc);
        // pc.onconnectionstatechange = (ev) => handleChange(pc)
        dc.onmessage = (ev) => self.onMessage(ev.data);
        dc.onopen = (ev) => {
            if (self._onConnected_cb) {
                self._onConnected_cb();
            }
            self._onConnected_cb = null;
        };
        dc.onerror = (ev) => console.log(`dc.onerror() ${ev}`);
        await pc.setLocalDescription(await pc.createOffer());
        return new Promise((resolve, reject) => {
            pc.onicecandidate = ({ candidate }) => {
                // console.log(`[createOffer()] onicecandidate() signalingState: ${this.pc.signalingState} candidate: ${candidate}`);
                if (candidate)
                    return;
                const offer = JSON.stringify(pc.localDescription);
                resolve(offer);
            };
        });
    }
    async handleInput(input) {
        console.log(`[handleInput()] input: ${input}`);
        if (!this.pc) {
            return await this.connectAndcreateOffer();
        }
        else if (this.pc.connectionState != "connected") {
            console.log(`[pc.connectionState == "${this.pc.connectionState}"]`);
            {
                const answer = JSON.parse(input);
                let self = this;
                const ret = new Promise((resolve, reject) => {
                    this._onConnected_cb = () => {
                        resolve("connected");
                    };
                    this.pc.setRemoteDescription(new RTCSessionDescription(answer));
                });
                return await ret;
            }
        }
        // if we got here we are connected
        // send message
        // wait for response
        const retP = new Promise((resolve, reject) => {
            this.dc.send(input);
            this._onMessage_cb = resolve;
        });
        let ret = await retP;
        console.log(`[handleInput()] ret: ${ret}`);
        return ret;
    }
}

/**
 * This executes shell commands over webrtc connection. It's not able to execute interactive commands like vim, prefer to use tee, etc instead";
 * @param cmd Valid shell command
*/
export async function webrtc_shell_cmd(cmd:string) {
    // cache the connection
    let rtc = window.rtc;
    if (!rtc) {
        window.rtc = rtc = new RTC();
        const offer = await rtc.handleInput("");
        let reply = prompt("Copy this offer to other node, and paste reply", offer);
        console.log("reply", reply);
        const replyReply = await rtc.handleInput(reply);
        console.log(`rtc.connected: ${rtc.connected}`);
        if (!rtc.connected) {
            return replyReply;
        }
        return webrtc_shell_cmd(cmd);
    }
    const replyStr = await rtc.handleInput(cmd);
    let output = replyStr;

    try {
        const reply = JSON.parse(replyStr);
        if (!reply.error) {
            output = reply.output.trim();
        }
    }
    catch (e) {
        output =
            replyStr +
            "\n" +
            `Caused error: ${e}`;
    }
    return '```\n' + output + '\n```';
}