[IMP] add recording feature

ThanhDodeurOdoo · ThanhDodeurOdoo · commit b371f93c99e7 · 2024-11-19T11:48:01.000+01:00
diff --git a/src/models/channel.js b/src/models/channel.js
@@ -5,6 +5,7 @@ import { getAllowedCodecs, Logger } from "#src/utils/utils.js";
 import { AuthenticationError, OvercrowdedError } from "#src/utils/errors.js";
 import { Session, SESSION_CLOSE_CODE } from "#src/models/session.js";
 import { getWorker } from "#src/services/rtc.js";
+import { Recorder } from "#src/models/recorder.js";
 
 const logger = new Logger("CHANNEL");
 
@@ -39,6 +40,7 @@ export class Channel extends EventEmitter {
     name;
     /** @type {WithImplicitCoercion<string>} base 64 buffer key */
     key;
+    recorder;
     /** @type {import("mediasoup").types.Router}*/
     router;
     /** @type {Map<number, Session>} */
@@ -130,6 +132,7 @@ export class Channel extends EventEmitter {
         this.name = `${remoteAddress}*${this.uuid.slice(-5)}`;
         this.router = router;
         this._worker = worker;
+        this.recorder = new Recorder(this);
         this._onSessionClose = this._onSessionClose.bind(this);
     }
 
@@ -249,6 +252,7 @@ export class Channel extends EventEmitter {
         }
         clearTimeout(this._closeTimeout);
         this.sessions.clear();
+        this.recorder.stop();
         Channel.records.delete(this.uuid);
         /**
          * @event Channel#close
diff --git a/src/models/recorder.js b/src/models/recorder.js
@@ -0,0 +1,186 @@
+import child_process from "node:child_process";
+import os from "node:os";
+import path from "node:path";
+import fs from "node:fs";
+
+import { EventEmitter } from "node:events"; // TODO remove if unnecessary
+import { Logger } from "#src/utils/utils.js";
+import { STREAM_TYPE } from "#src/shared/enums.js";
+
+const logger = new Logger("RECORDER");
+const temp = os.tmpdir();
+const FORMAT = "mp4"; // TODO config
+const VIDEO_LIMIT = 4; // TODO config (and other name?)
+
+/**
+ * @typedef {Object} RTPTransports
+ * @property {Array<import("mediasoup").types.Transport>} audio
+ * @property {Array<import("mediasoup").types.Transport>} camera
+ * @property {Array<import("mediasoup").types.Transport>} screen
+ */
+
+/**
+ * Wraps the FFMPEG process
+ * TODO move in own file
+ */
+class FFMPEG extends EventEmitter {
+    /** @type {child_process.ChildProcess} */
+    _process;
+    /** @type {string} */
+    _filePath;
+
+    get _args() {
+        return [
+            "-loglevel",
+            "debug", // TODO warning in prod
+            "-protocol_whitelist",
+            "pipe,udp,rtp",
+            "-fflags",
+            "+genpts",
+            "-f",
+            "sdp",
+            "-i",
+            "pipe:0",
+            "-movflags",
+            "frag_keyframe+empty_moov+default_base_moof", // fragmented
+            "-c:v",
+            "libx264", // vid codec
+            "-c:a",
+            "aac", // audio codec
+            "-f",
+            FORMAT,
+            this._filePath,
+        ];
+    }
+
+    /**
+     * @param {string} filePath
+     */
+    constructor(filePath) {
+        super();
+        this._filePath = filePath;
+    }
+
+    /**
+     * @param {String[]} [sdp]
+     */
+    async spawn(sdp) {
+        this._process = child_process.spawn("ffmpeg", this._args, {
+            stdio: ["pipe", "pipe", process.stderr],
+        });
+
+        if (!this._process.stdin.writable) {
+            throw new Error("FFMPEG stdin not writable.");
+        }
+        this._process.stdin.write(sdp);
+        this._process.stdin.end();
+
+        this._process.stdout.on("data", (chunk) => {
+            this.emit("data", chunk); // Emit data chunks as they become available
+        });
+
+        this._process.on("close", (code) => {
+            if (code === 0) {
+                this.emit("success");
+            }
+        });
+
+        logger.debug(
+            `FFMPEG process (pid:${this._process.pid}) spawned, outputting to ${this._filePath}`
+        );
+    }
+
+    kill() {
+        this._process?.kill("SIGINT");
+    }
+}
+
+export class Recorder extends EventEmitter {
+    static records = new Map();
+
+    /** @type {string} */
+    uuid = crypto.randomUUID();
+    /** @type {import("#src/models/channel").Channel} */
+    channel;
+    /** @type {string} */
+    state;
+    ffmpeg;
+    /** @type {RTPTransports} */
+    _rtpTransports;
+    /** @type {string} */
+    filePath;
+    /**
+     * @param {import("#src/models/channel").Channel} channel
+     */
+    constructor(channel) {
+        super();
+        this.channel = channel;
+        this.filePath = path.join(temp, `${this.uuid}.${FORMAT}`);
+        Recorder.records.set(this.uuid, this);
+    }
+
+    /** @returns {number} */
+    get videoCount() {
+        return this._rtpTransports.camera.length + this._rtpTransports.screen.length;
+    }
+
+    /**
+     * @param {Array} ids
+     * @returns {string} filePath
+     */
+    start(ids) {
+        // maybe internal state and check if already recording (recording = has ffmpeg child process).
+        this.stop();
+        for (const id of ids) {
+            const session = this.channel.sessions.get(id);
+            const audioRtp = this._createRtp(
+                session.producers[STREAM_TYPE.AUDIO],
+                STREAM_TYPE.AUDIO
+            );
+            audioRtp && this._rtpTransports.audio.push(audioRtp);
+            for (const type in [STREAM_TYPE.CAMERA, STREAM_TYPE.SCREEN]) {
+                if (this.videoCount < VIDEO_LIMIT) {
+                    const rtp = this._createRtp(session.producers[type], type);
+                    rtp && this._rtpTransports[type].push(rtp);
+                }
+            }
+        }
+        this.ffmpeg = new FFMPEG(this.filePath);
+        this.ffmpeg.spawn(); // args should be base on the rtp transports
+        this.ffmpeg.once("success", () => {
+            this.emit("download-ready", this.filePath);
+        });
+        return this.filePath;
+    }
+    pause() {
+        // TODO maybe shouldn't be able to pause
+    }
+    stop() {
+        // TODO
+        // cleanup all rtp transports
+        // stop ffmpeg process
+        Recorder.records.delete(this.uuid);
+    }
+
+    /**
+     * @param {http.ServerResponse} res
+     */
+    pipeToResponse(res) {
+        // TODO check if this can be executed, otherwise end request?
+        const fileStream = fs.createReadStream(this._filePath);
+        res.writeHead(200, {
+            "Content-Type": `video/${FORMAT}`,
+            "Content-Disposition": "inline",
+        });
+        fileStream.pipe(res); // Pipe the file stream to the response
+    }
+
+    /**
+     * @param {import("mediasoup").types.Producer} producer
+     * @param {STREAM_TYPE[keyof STREAM_TYPE]} type
+     * @return {Promise<void>} probably just create transport with right ports and return that,
+     */
+    async _createRtp(producer, type) {
+        // TODO
+    }
+}
diff --git a/src/services/http.js b/src/services/http.js
@@ -6,6 +6,7 @@ import * as config from "#src/config.js";
 import { Logger, parseBody, extractRequestInfo } from "#src/utils/utils.js";
 import { SESSION_CLOSE_CODE } from "#src/models/session.js";
 import { Channel } from "#src/models/channel.js";
+import { Recorder } from "#src/models/recorder.js";
 
 /**
  * @typedef {function} routeCallback
@@ -15,6 +16,7 @@ import { Channel } from "#src/models/channel.js";
  * @param {string} param2.remoteAddress
  * @param {string} param2.protocol
  * @param {string} param2.host
+ * @param {Object} param2.match name/value mapping of route variables
  * @param {URLSearchParams} param2.searchParams
  * @return {http.ServerResponse}
  */
@@ -77,6 +79,19 @@ export async function start({ httpInterface = config.HTTP_INTERFACE, port = conf
             return res.end();
         },
     });
+    routeListener.get(`/v${API_VERSION}/recording/<token>`, {
+        callback: async (req, res, { remoteAddress, match }) => {
+            try {
+                const { token } = match;
+                logger.info(`[${remoteAddress}]: requested recording ${token}`);
+                Recorder.records.get(token)?.pipeToResponse(res);
+                // res not ended as we are streaming
+            } catch (error) {
+                logger.error(`[${remoteAddress}] failed to obtain recording: ${error.message}`);
+                return res.end();
+            }
+        },
+    });
     routeListener.post(`/v${API_VERSION}/disconnect`, {
         callback: async (req, res, { remoteAddress }) => {
             try {
@@ -183,7 +198,8 @@ class RouteListener {
                 break;
         }
         for (const [pattern, options] of registeredRoutes) {
-            if (pathname === pattern) {
+            const match = this._extractPattern(pathname, pattern);
+            if (match) {
                 if (options?.cors) {
                     res.setHeader("Access-Control-Allow-Origin", options.cors);
                     res.setHeader("Access-Control-Allow-Methods", options.methods);
@@ -195,6 +211,7 @@ class RouteListener {
                             host,
                             protocol,
                             remoteAddress,
+                            match,
                             searchParams,
                         });
                     } catch (error) {
@@ -212,4 +229,32 @@ class RouteListener {
         }
         return res.end();
     }
+
+    /**
+     * Matches a pathname against a pattern with named parameters.
+     * @param {string} pathname - The URL path requested, e.g., "/channel/6/person/42/"
+     * @param {string} pattern - The pattern to match, e.g., "/channel/<channelId>/session/<sessionId>"
+     * @returns {object|undefined} - Returns undefined if no match. If matched, returns an object mapping keys to values,
+     * the object is empty if matching a pattern with no variables.
+     * eg: { channelId: "6", sessionId: "42" } | {} | undefined
+     */
+    _extractPattern(pathname, pattern) {
+        pathname = pathname.replace(/\/+$/, "");
+        pattern = pattern.replace(/\/+$/, "");
+        const paramNames = [];
+        const regexPattern = pattern.replace(/<([^>]+)>/g, (_, paramName) => {
+            paramNames.push(paramName);
+            return "([^/]+)";
+        });
+        const regex = new RegExp(`^${regexPattern}$`);
+        const match = pathname.match(regex);
+        if (!match) {
+            return;
+        }
+        const params = {};
+        paramNames.forEach((name, index) => {
+            params[name] = match[index + 1];
+        });
+        return params;
+    }
 }
diff --git a/src/shared/enums.js b/src/shared/enums.js
@@ -12,6 +12,12 @@ export const WS_CLOSE_CODE = {
     CHANNEL_FULL: 4109,
 };
 
+export const STREAM_TYPE = {
+    AUDIO: "audio",
+    CAMERA: "camera",
+    SCREEN: "screen",
+};
+
 export const SERVER_REQUEST = {
     /** Requests the creation of a consumer that is used to forward a track to the client */
     INIT_CONSUMER: "INIT_CONSUMER",
