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/*
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 *  This file is part of CoCalc: Copyright © 2022 Sagemath, Inc.
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 *  License: MS-RSL – see LICENSE.md for details
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 */
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/*
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This is an express http server that is meant to receive connections
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only from web browser clients that signed in as collaborators on
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this projects.  It serves both HTTP and websocket connections, which
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should be proxied through some hub.
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*/
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import compression from "compression";
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import express from "express";
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import { createServer } from "http";
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import { writeFile } from "node:fs/promises";
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import { join } from "node:path";
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import basePath from "@cocalc/backend/base-path";
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import initWebsocket from "@cocalc/project/browser-websocket/server";
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import initWebsocketFs from "../websocketfs";
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import initSyncFs from "../sync-fs";
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import { browserPortFile, project_id } from "@cocalc/project/data";
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import initDirectoryListing from "@cocalc/project/directory-listing";
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import { getOptions } from "@cocalc/project/init-program";
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import * as kucalc from "@cocalc/project/kucalc";
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import { getLogger } from "@cocalc/project/logger";
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import { once } from "@cocalc/util/async-utils";
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import initRootSymbolicLink from "./root-symlink";
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const winston = getLogger("browser-http-server");
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export default async function init(): Promise<void> {
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  winston.info("starting server...");
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  const base = join(basePath, project_id, "raw") + "/";
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  const app = express();
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  app.disable("x-powered-by"); // https://github.com/sagemathinc/cocalc/issues/6101
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  const server = createServer(app);
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  // WEBSOCKET SERVERS
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  // **CRITICAL:** This *must* be above the app.use(compression())
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  // middleware below, since compressing/uncompressing the websocket
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  // would otherwise happen, and that slows it down a lot.
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  // Setup the ws websocket server, which is used by clients
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  // for direct websocket connections to the project, and also
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  // serves primus.js, which is the relevant client library.
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  winston.info("initializing websocket server");
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  // We have to explicitly also include the base as a parameter
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  // to initWebsocket, since of course it makes deeper user of server.
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  app.use(base, initWebsocket(server, base));
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  initWebsocketFs(server, base);
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  // This uses its own internal lz4 compression:
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  initSyncFs(server, base);
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  // CRITICAL: keep this after the websocket stuff or anything you do not
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  // want to have compressed.
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  // suggested by http://expressjs.com/en/advanced/best-practice-performance.html#use-gzip-compression
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  app.use(compression());
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  winston.info("creating root symbolic link");
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  await initRootSymbolicLink();
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  if (kucalc.IN_KUCALC) {
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    // Add /health (used as a health check for Kubernetes) and /metrics (Prometheus)
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    winston.info("initializing KuCalc only health metrics server");
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    kucalc.init_health_metrics(app, project_id);
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  }
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  // Setup the directory_listing/... server, which is used to provide directory listings
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  // to the hub (at least in KuCalc).  It is still used by HUB!  But why?  Maybe it is only
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  // for the deprecated public access to a project?  If so, we can get rid of all of that.
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  winston.info("initializing directory listings server (DEPRECATED)");
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  app.use(base, initDirectoryListing());
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  const options = getOptions();
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  server.listen(options.browserPort, options.hostname);
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  await once(server, "listening");
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  const address = server.address();
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  if (address == null || typeof address == "string") {
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    // null = failed; string doesn't happen since that's for unix domain
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    // sockets, which we aren't using.
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    // This is probably impossible, but it makes typescript happier.
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    throw Error("failed to assign a port");
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  }
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  const assignedPort = address.port; // may be a server assigned random port.
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  winston.info(
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    `Started -- port=${assignedPort}, host='${options.hostname}', base='${base}'`,
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  );
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  winston.info(`Writing port to ${browserPortFile}`);
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  await writeFile(browserPortFile, `${assignedPort}`);
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}
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