adapter.ts

import * as fs from 'node:fs';
import { serve } from "https://deno.land/std@0.211.0/http/server.ts";
import { STATUS_CODE } from "https://deno.land/std@0.211.0/http/status.ts";
import { create, getNumericDate } from "https://deno.land/x/djwt@v3.0.1/mod.ts";
import { Algorithm } from "https://deno.land/x/djwt@v3.0.1/algorithm.ts";
import {
  DEBUG,
  HOSTNAME,
  JWT_ALG,
  JWT_APP_ID,
  JWT_APP_SECRET,
  JWT_EXP_SECOND,
  JWT_HASH,
  KEYCLOAK_CLIENT_ID,
  KEYCLOAK_MODE,
  KEYCLOAK_ORIGIN,
  KEYCLOAK_ORIGIN_INTERNAL,
  KEYCLOAK_REALM,
  PORT,
  PERMISSIONS_FILE
} from "./config.ts";
import { createContext } from "./context.ts";

// -----------------------------------------------------------------------------
// HTTP response for OK
// -----------------------------------------------------------------------------
function ok(body: string): Response {
  return new Response(body, {
    status: STATUS_CODE.OK,
  });
}

// -----------------------------------------------------------------------------
// HTTP response for NotFound
// -----------------------------------------------------------------------------
function notFound(): Response {
  return new Response(null, {
    status: STATUS_CODE.NotFound,
  });
}

// -----------------------------------------------------------------------------
// HTTP response for MethodNotAllowed
// -----------------------------------------------------------------------------
function methodNotAllowed(): Response {
  return new Response(null, {
    status: STATUS_CODE.MethodNotAllowed,
  });
}

// -----------------------------------------------------------------------------
// HTTP response for Unauthorized
// -----------------------------------------------------------------------------
function unauthorized(): Response {
  return new Response(null, {
    status: STATUS_CODE.Unauthorized,
  });
}

// -----------------------------------------------------------------------------
// Generate JWT (Jitsi token)
// -----------------------------------------------------------------------------
async function generateJWT(
  userInfo: Record<string, unknown>,
  room: string
): Promise<string | undefined> {
  try {

    const encoder = new TextEncoder();
    const keyData = encoder.encode(JWT_APP_SECRET);
    const cryptoKey = await crypto.subtle.importKey(
      "raw",
      keyData,
      {
        name: "HMAC",
        hash: JWT_HASH,
      },
      true,
      ["sign", "verify"],
    );

    const alg = JWT_ALG as Algorithm;
    const header = { alg: alg, typ: "JWT" };
    const payload = {
      aud: JWT_APP_ID,
      iss: JWT_APP_ID,
      sub: "*",
      room: room,
      iat: getNumericDate(0),
      nbf: getNumericDate(0),
      exp: getNumericDate(JWT_EXP_SECOND),
      context: createContext(userInfo),
    };

    return await create(header, payload, cryptoKey);
  } catch {
    return undefined;
  }
}

// -----------------------------------------------------------------------------
// Get the access token from Keycloak by using the short-term auth code
//
// redirect_uri should be the same with URI which is set while getting the
// short-term authorization code but actually there is no redirection at this
// stage. This is for security check only.
// -----------------------------------------------------------------------------
async function getToken(
  host: string,
  code: string,
  path: string,
  search: string,
  hash: string,
): Promise<string | undefined> {
  const url = `${KEYCLOAK_ORIGIN_INTERNAL}/realms/${KEYCLOAK_REALM}` +
    `/protocol/openid-connect/token`;
  const bundle = `path=${encodeURIComponent(path)}` +
    `&search=${encodeURIComponent(search)}` +
    `&hash=${encodeURIComponent(hash)}`;
  const redirectURI = `https://${host}/static/oidc-adapter.html` +
    `?${bundle}`;
  const data = new URLSearchParams();
  data.append("client_id", KEYCLOAK_CLIENT_ID);
  data.append("grant_type", "authorization_code");
  data.append("redirect_uri", redirectURI);
  data.append("code", code);

  if (DEBUG) console.log(`getToken url: ${url}`);
  if (DEBUG) console.log(`getToken redirectURI: ${redirectURI}`);
  if (DEBUG) console.log(`getToken data:`);
  if (DEBUG) console.log(data);

  try {
    const res = await fetch(url, {
      headers: {
        "Accept": "application/json",
      },
      method: "POST",
      body: data,
    });
    const json = await res.json();
    const token = json.access_token;

    if (DEBUG) console.log(`getToken json:`);
    if (DEBUG) console.log(json);

    if (!token) throw ("cannot get Keycloak token");

    return token;
  } catch {
    return undefined;
  }
}

// -----------------------------------------------------------------------------
// Get the user info from Keycloak by using the access token
// -----------------------------------------------------------------------------
async function getUserInfo(
  token: string,
): Promise<Record<string, unknown> | undefined> {
  try {
    const url = `${KEYCLOAK_ORIGIN_INTERNAL}/realms/${KEYCLOAK_REALM}` +
      `/protocol/openid-connect/userinfo`;
    const res = await fetch(url, {
      headers: {
        "Accept": "application/json",
        "Authorization": `Bearer ${token}`,
      },
      method: "GET",
    });
    const userInfo = await res.json();

    if (DEBUG) console.log(`getUserInfo userInfo:`);
    if (DEBUG) console.log(userInfo);

    // sub is the mandotary field for successful request
    if (!userInfo.sub) throw ("no user info");

    return await userInfo;
  } catch {
    return undefined;
  }
}

// -----------------------------------------------------------------------------
// Send the Jitsi token if auth is OK
// -----------------------------------------------------------------------------
async function tokenize(req: Request): Promise<Response> {
  const host = req.headers.get("host");
  const url = new URL(req.url);
  const qs = new URLSearchParams(url.search);
  const code = qs.get("code");
  const path = qs.get("path") || "";
  const search = qs.get("search") || "";
  const hash = qs.get("hash") || "";

  if (DEBUG) console.log(`tokenize code: ${code}`);

  // host is needed for redirection. If no host, this is not a valid request.
  if (!host) return unauthorized();

  // only the currently logged in user has a short-term auth code
  if (!code) return unauthorized();

  // get the access token from Keycloak if the short-term auth code is valid
  const token = await getToken(host, code, path, search, hash);
  if (!token) {
    if (DEBUG) console.log(`Could not get Keycloak's access token`);
    return unauthorized();
  }

  // get the user info from Keycloak by using the access token
  const userInfo = await getUserInfo(token);
  if (!userInfo) return unauthorized();

  // Enhance userinfo
  userInfo["lobby_bypass"] = true;
  userInfo["security_bypass"] = true;
  userInfo["affiliation"] = "owner";
  let tokenRoom = "*"

  // Loading permissions
  if (PERMISSIONS_FILE) {
    if (fs.existsSync(PERMISSIONS_FILE)) {
      let permissions: any = [];
      const rawData = fs.readFileSync(PERMISSIONS_FILE, 'utf-8');
      permissions = JSON.parse(rawData);
      // now you can use the 'permissions' object
      console.log(`Loaded ${permissions.length} permissions from ${PERMISSIONS_FILE}`)

      let roomName = path.slice(1);

      let room = permissions.find(r => r.room === roomName);

      if (room) {
        // Check for lobby settings
        const lobby = room.useLobby



        const userName = userInfo["email"]
        console.log(`Found config for room ${roomName}. Checking for user ${userName}`)
        tokenRoom = roomName;
        // check if the user is in the moderator list
        if (room.moderators.includes(userName)) {
          console.log(`${userName} is a moderator of ${roomName}`);
          // make use owner
          userInfo["affiliation"] = "owner";
        }
        else {
          console.log(`${userName} is not a moderator of ${roomName}`);
          // reduce permissions
          userInfo["affiliation"] = "member";
          if (lobby) {
            userInfo["lobby_bypass"] = false;
          }

        }
      } else {
        console.log(`room ${roomName} not found in permissions.`);
      }

    } else {
      console.error(`File not found: ${PERMISSIONS_FILE} - No permissions loaded.`);
    }
  }


  // generate JWT
  const jwt = await generateJWT(userInfo, tokenRoom);

  if (DEBUG) console.log(`tokenize token: ${jwt}`);

  return new Response(JSON.stringify(jwt), {
    status: STATUS_CODE.OK,
  });
}

// -----------------------------------------------------------------------------
// Redirect to Keycloak auth service to get a short-term authorization code.
//
// If successful, Keycloak will redirect the request to oidc-adapter.html
// (redirect_uri) with a short-term authorization code.
// -----------------------------------------------------------------------------
function oidcRedirectForCode(req: Request, prompt: string): Response {
  const host = req.headers.get("host");
  const url = new URL(req.url);
  const qs = new URLSearchParams(url.search);
  const path = qs.get("path");
  const search = qs.get("search") || "";
  const hash = qs.get("hash") || "";

  if (!host) throw ("missing host");
  if (!path) throw ("missing path");

  const bundle = `path=${encodeURIComponent(path)}` +
    `&search=${encodeURIComponent(search)}` +
    `&hash=${encodeURIComponent(hash)}`;
  const target = `${KEYCLOAK_ORIGIN}/realms/${KEYCLOAK_REALM}` +
    `/protocol/openid-connect/auth?client_id=${KEYCLOAK_CLIENT_ID}` +
    `&response_mode=${KEYCLOAK_MODE}&response_type=code&scope=openid` +
    `&prompt=${prompt}&redirect_uri=https://${host}/static/oidc-adapter.html` +
    `?${encodeURIComponent(bundle)}`;

  if (DEBUG) console.log(`oidcRedirectForCode prompt: ${prompt}`);
  if (DEBUG) console.log(`oidcRedirectForCode host: ${host}`);
  if (DEBUG) console.log(`oidcRedirectForCode path: ${path}`);
  if (DEBUG) console.log(`oidcRedirectForCode search: ${search}`);
  if (DEBUG) console.log(`oidcRedirectForCode hash: ${hash}`);
  if (DEBUG) console.log(`oidcRedirectForCode bundle: ${bundle}`);
  if (DEBUG) console.log(`oidcRedirectForCode target: ${target}`);

  return Response.redirect(target, STATUS_CODE.Found);
}

// -----------------------------------------------------------------------------
// Redirect to Keycloak auth service to get a short-term authorization code.
// Don't ask for a credential if auth fails
// -----------------------------------------------------------------------------
function redirect(req: Request): Response {
  return oidcRedirectForCode(req, "none");
}

// -----------------------------------------------------------------------------
// Redirect to Keycloak auth service to get a short-term authorization code.
// Ask for a credential if auth fails
// -----------------------------------------------------------------------------
function auth(req: Request): Response {
  return oidcRedirectForCode(req, "login");
}

function generateGUID() {
  function s4() {
    return Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1);
  }
  return `${s4()}${s4()}-${s4()}-${s4()}-${s4()}-${s4()}${s4()}${s4()}`;
}

async function yolo_auth(req: Request): Response {
  // Don't go to keycloak if the room name is prefixed yolo_ and just create a usable JWT
  const host = req.headers.get("host");
  const url = new URL(req.url);
  const qs = new URLSearchParams(url.search);
  const path = qs.get("path");
  const search = qs.get("search") || "";
  const hash = qs.get("hash") || "";

  console.log("Got a yolo requerst for " + path)

  // check if it's really a yolo
  if (!path.startsWith("yolo_")) {
    console.log("Not yolo. aborting.")
    return new Response("no-yolo", {
      status: STATUS_CODE.FORBIDDEN,
    });
  }

  // Generate JWT
  const userInfo = {
    "sub": generateGUID(),
    "preferred_username": "Fellow Jitster",
    "email": "jitsi@example.com",
    "lobby_bypass": true,
    "security_bypass": true,
    "affiliation": "owner"
  }
  let roomName = path;
  const jwt = await generateJWT(userInfo, roomName);

  if (DEBUG) console.log(`tokenize token: ${jwt}`);

  const redirectUrl = '/' + path + '?oidc=authenticated&jwt=' + jwt;

  // Create a Response object with a 302 redirect status
  return new Response(null, {
    status: 302,
    headers: {
      'Location': redirectUrl
    }
  });
}

// bypass auth function for monitoring
async function monitoring_auth(req: Request): Promise<Response> {
  const url = new URL(req.url);
  const qs = new URLSearchParams(url.search);
  const path = qs.get("path");

  console.log("Got a monitoring request for " + path);

  // check it's amonitoring request
  if (!path?.startsWith("jitsimonitoring_aml0c2lt")) {
    console.log("Not a monitoring request. Aborting.")
    return new Response("not-monitoring", {
      status: STATUS_CODE.FORBIDDEN,
    });
  }

  // Generate JWT with monitoring userInfo
  const userInfo = {
    "sub": "monitoring-" + generateGUID(),
    "preferred_username": "Jitsi Monitor",
    "email": "monitor@jitsi.local",
    "lobby_bypass": true,
    "security_bypass": true,
    "affiliation": "owner"
  }

  const jwt = await generateJWT(userInfo, path);

  if (DEBUG) console.log(`monitoring token: ${jwt}`);

  const redirectUrl = '/' + path + '?oidc=authenticated&jwt=' + jwt;

  return new Response(null, {
    status: 302,
    headers: {
      'Location': redirectUrl
    }
  });
}

// -----------------------------------------------------------------------------
// handler
// -----------------------------------------------------------------------------
async function handler(req: Request): Promise<Response> {
  const url = new URL(req.url);
  const path = url.pathname;

  if (req.method !== "GET") return methodNotAllowed();

  if (path === "/health") {
    return ok("healthy");
  } else if (path === "/oidc/health") {
    return ok("healthy");
  } else if (path === "/oidc/yolo") {
    return await yolo_auth(req);
  } else if (path === "/oidc/monitoring") {
    return await monitoring_auth(req);
  } else if (path === "/oidc/redirect") {
    return redirect(req);
  } else if (path === "/oidc/tokenize") {
    return await tokenize(req);
  } else if (path === "/oidc/auth") {
    return await auth(req);
  } else {
    return notFound();
  }
}

// -----------------------------------------------------------------------------
// main
// -----------------------------------------------------------------------------
function main() {
  console.log(`KEYCLOAK_ORIGIN: ${KEYCLOAK_ORIGIN}`);
  console.log(`KEYCLOAK_ORIGIN_INTERNAL: ${KEYCLOAK_ORIGIN_INTERNAL}`);
  console.log(`KEYCLOAK_REALM: ${KEYCLOAK_REALM}`);
  console.log(`KEYCLOAK_CLIENT_ID: ${KEYCLOAK_CLIENT_ID}`);
  console.log(`KEYCLOAK_MODE: ${KEYCLOAK_MODE}`);
  console.log(`JWT_ALG: ${JWT_ALG}`);
  console.log(`JWT_HASH: ${JWT_HASH}`);
  console.log(`JWT_APP_ID: ${JWT_APP_ID}`);
  console.log(`JWT_APP_SECRET: *** masked ***`);
  console.log(`JWT_EXP_SECOND: ${JWT_EXP_SECOND}`);
  console.log(`HOSTNAME: ${HOSTNAME}`);
  console.log(`PORT: ${PORT}`);
  console.log(`DEBUG: ${DEBUG}`);
  if (PERMISSIONS_FILE) {
    console.log(`PERMISSIONS_FILE: ${PERMISSIONS_FILE}`);
  }

  serve(handler, {
    hostname: HOSTNAME,
    port: PORT
  });
}

// -----------------------------------------------------------------------------
main();