/**
* AppServer serves up the main app.html file to the browser. It is the first point of contact of
* a browser with Grist. It handles sessions, redirect-to-login, and serving up a suitable version
* of the client-side code.
*/
import * as express from 'express';
import fetch, {Response as FetchResponse, RequestInit} from 'node-fetch';
import {ApiError} from 'app/common/ApiError';
import {getSlugIfNeeded, parseSubdomainStrictly} from 'app/common/gristUrls';
import {removeTrailingSlash} from 'app/common/gutil';
import {LocalPlugin} from "app/common/plugin";
import {Document as APIDocument} from 'app/common/UserAPI';
import {Document} from "app/gen-server/entity/Document";
import {HomeDBManager} from 'app/gen-server/lib/HomeDBManager';
import {assertAccess, getTransitiveHeaders, getUserId, isAnonymousUser,
RequestWithLogin} from 'app/server/lib/Authorizer';
import {DocStatus, IDocWorkerMap} from 'app/server/lib/DocWorkerMap';
import {expressWrap} from 'app/server/lib/expressWrap';
import {DocTemplate, GristServer} from 'app/server/lib/GristServer';
import {getAssignmentId} from 'app/server/lib/idUtils';
import log from 'app/server/lib/log';
import {adaptServerUrl, addOrgToPathIfNeeded, pruneAPIResult, trustOrigin} from 'app/server/lib/requestUtils';
import {ISendAppPageOptions} from 'app/server/lib/sendAppPage';
export interface AttachOptions {
app: express.Application; // Express app to which to add endpoints
middleware: express.RequestHandler[]; // Middleware to apply for all endpoints except docs
docMiddleware: express.RequestHandler[]; // Middleware to apply for doc landing pages
forceLogin: express.RequestHandler|null; // Method to force user to login (if logins are possible)
docWorkerMap: IDocWorkerMap|null;
sendAppPage: (req: express.Request, resp: express.Response, options: ISendAppPageOptions) => Promise<void>;
dbManager: HomeDBManager;
plugins: LocalPlugin[];
gristServer: GristServer;
}
/**
* This method transforms a doc worker's public url as needed based on the request.
*
* For historic reasons, doc workers are assigned a public url at the time
* of creation. In production/staging, this is of the form:
* https://doc-worker-NNN-NNN-NNN-NNN.getgrist.com/v/VVVV/
* and in dev:
* http://localhost:NNNN/v/VVVV/
*
* Prior to support for different base domains, this was fine. Now that different
* base domains are supported, a wrinkle arises. When a web client communicates
* with a doc worker, it is important that it accesses the doc worker via a url
* containing the same base domain as the web page the client is on (for cookie
* purposes). Hence this method.
*
* If both the request and docWorkerUrl contain identifiable base domains (not localhost),
* then the base domain of docWorkerUrl is replaced with that of the request.
*
* But wait, there's another wrinkle: custom domains. In this case, we have a single
* domain available to serve a particular org from. This method will use the origin of req
* and include a /dw/doc-worker-NNN-NNN-NNN-NNN/
* (or /dw/local-NNNN/) prefix in all doc worker paths. Once this is in place, it
* will allow doc worker routing to be changed so it can be overlaid on a custom
* domain.
*
* TODO: doc worker registration could be redesigned to remove the assumption
* of a fixed base domain.
*/
function customizeDocWorkerUrl(docWorkerUrlSeed: string|undefined, req: express.Request): string|null {
if (!docWorkerUrlSeed) {
// When no doc worker seed, we're in single server mode.
// Return null, to signify that the URL prefix serving the
// current endpoint is the only one available.
return null;
}
const docWorkerUrl = new URL(docWorkerUrlSeed);
const workerSubdomain = parseSubdomainStrictly(docWorkerUrl.hostname).org;
adaptServerUrl(docWorkerUrl, req);
// We wish to migrate to routing doc workers by path, so insert a doc worker identifier
// in the path (if not already present).
if (!docWorkerUrl.pathname.startsWith('/dw/')) {
// When doc worker is localhost, the port number is necessary and sufficient for routing.
// Let's add a /dw/... prefix just for consistency.
const workerIdent = workerSubdomain || `local-${docWorkerUrl.port}`;
docWorkerUrl.pathname = `/dw/${workerIdent}${docWorkerUrl.pathname}`;
}
return docWorkerUrl.href;
}
/**
*
* Gets the worker responsible for a given assignment, and fetches a url
* from the worker.
*
* If the fetch fails, we throw an exception, unless we see enough evidence
* to unassign the worker and try again.
*
* - If GRIST_MANAGED_WORKERS is set, we assume that we've arranged
* for unhealthy workers to be removed automatically, and that if a
* fetch returns a 404 with specific content, it is proof that the
* worker is no longer in existence. So if we see a 404 with that
* specific content, we can safely de-list the worker from redis,
* and repeat.
* - If GRIST_MANAGED_WORKERS is not set, we accept a broader set
* of failures as evidence of a missing worker.
*
* The specific content of a 404 that will be treated as evidence of
* a doc worker not being present is:
* - A json format body
* - With a key called "message"
* - With the value of "message" being "document worker not present"
* In production, this is provided by a special doc-worker-* load balancer
* rule.
*
*/
async function getWorker(docWorkerMap: IDocWorkerMap, assignmentId: string,
urlPath: string, config: RequestInit = {}) {
if (!useWorkerPool()) {
// This should never happen. We are careful to not use getWorker
// when everything is on a single server, since it is burdensome
// for self-hosted users to figure out the correct settings for
// the server to be able to contact itself, and there are cases
// of the defaults not working.
throw new Error("AppEndpoint.getWorker was called unnecessarily");
}
let docStatus: DocStatus|undefined;
const workersAreManaged = Boolean(process.env.GRIST_MANAGED_WORKERS);
for (;;) {
docStatus = await docWorkerMap.assignDocWorker(assignmentId);
const configWithTimeout = {timeout: 10000, ...config};
const fullUrl = removeTrailingSlash(docStatus.docWorker.internalUrl) + urlPath;
try {
const resp: FetchResponse = await fetch(fullUrl, configWithTimeout);
if (resp.ok) {
return {
resp,
docStatus,
};
}
if (resp.status === 403) {
throw new ApiError("You do not have access to this document.", resp.status);
}
if (resp.status !== 404) {
throw new ApiError(resp.statusText, resp.status);
}
let body: any;
try {
body = await resp.json();
} catch (e) {
throw new ApiError(resp.statusText, resp.status);
}
if (!(body && body.message && body.message === 'document worker not present')) {
throw new ApiError(resp.statusText, resp.status);
}
// This is a 404 with the expected content for a missing worker.
} catch (e) {
log.rawDebug(`AppEndpoint.getWorker failure`, {
url: fullUrl,
docId: assignmentId,
status: e.status,
message: String(e),
workerId: docStatus.docWorker.id,
});
// If workers are managed, no errors merit continuing except a 404.
// Otherwise, we continue if we see a system error (e.g. ECONNREFUSED).
// We don't accept timeouts since there is too much potential to
// bring down a single-worker deployment that has a hiccup.
if (workersAreManaged || !(e.type === 'system')) {
throw e;
}
}
log.warn(`fetch from ${fullUrl} failed convincingly, removing that worker`);
await docWorkerMap.removeWorker(docStatus.docWorker.id);
docStatus = undefined;
}
}
export function attachAppEndpoint(options: AttachOptions): void {
const {app, middleware, docMiddleware, docWorkerMap, forceLogin,
sendAppPage, dbManager, plugins, gristServer} = options;
// Per-workspace URLs open the same old Home page, and it's up to the client to notice and
// render the right workspace.
app.get(['/', '/ws/:wsId', '/p/:page'], ...middleware, expressWrap(async (req, res) =>
sendAppPage(req, res, {path: 'app.html', status: 200, config: {plugins}, googleTagManager: 'anon'})));
app.get('/api/worker/:assignmentId([^/]+)/?*', expressWrap(async (req, res) => {
if (!useWorkerPool()) {
// Let the client know there is not a separate pool of workers,
// so they should continue to use the same base URL for accessing
// documents. For consistency, return a prefix to add into that
// URL, as there would be for a pool of workers. It would be nice
// to go ahead and provide the full URL, but that requires making
// more assumptions about how Grist is configured.
// Alternatives could be: have the client to send their base URL
// in the request; or use headers commonly added by reverse proxies.
const selfPrefix = "/dw/self/v/" + gristServer.getTag();
res.json({docWorkerUrl: null, selfPrefix});
return;
}
if (!trustOrigin(req, res)) { throw new Error('Unrecognized origin'); }
res.header("Access-Control-Allow-Credentials", "true");
if (!docWorkerMap) {
return res.status(500).json({error: 'no worker map'});
}
const assignmentId = getAssignmentId(docWorkerMap, req.params.assignmentId);
const {docStatus} = await getWorker(docWorkerMap, assignmentId, '/status');
if (!docStatus) {
return res.status(500).json({error: 'no worker'});
}
res.json({docWorkerUrl: customizeDocWorkerUrl(docStatus.docWorker.publicUrl, req)});
}));
// Handler for serving the document landing pages. Expects the following parameters:
// urlId, slug (optional), remainder
// This handler is used for both "doc/urlId" and "urlId/slug" style endpoints.
const docHandler = expressWrap(async (req, res, next) => {
if (req.params.slug && req.params.slug === 'app.html') {
// This can happen on a single-port configuration, since "docId/app.html" matches
// the "urlId/slug" pattern. Luckily the "." character is not allowed in slugs.
return next();
}
if (!docWorkerMap) {
return await sendAppPage(req, res, {path: 'app.html', status: 200, config: {plugins},
googleTagManager: 'anon'});
}
const mreq = req as RequestWithLogin;
const urlId = req.params.urlId;
let doc: Document|null = null;
try {
const userId = getUserId(mreq);
// Query DB for the doc metadata, to include in the page (as a pre-fetch of getDoc() call),
// and to get fresh (uncached) access info.
doc = await dbManager.getDoc({userId, org: mreq.org, urlId});
const slug = getSlugIfNeeded(doc);
const slugMismatch = (req.params.slug || null) !== (slug || null);
const preferredUrlId = doc.urlId || doc.id;
if (urlId !== preferredUrlId || slugMismatch) {
// Prepare to redirect to canonical url for document.
// Preserve any query parameters or fragments.
const queryOrFragmentCheck = req.originalUrl.match(/([#?].*)/);
const queryOrFragment = (queryOrFragmentCheck && queryOrFragmentCheck[1]) || '';
const target = slug ?
`/${preferredUrlId}/${slug}${req.params.remainder}${queryOrFragment}` :
`/doc/${preferredUrlId}${req.params.remainder}${queryOrFragment}`;
res.redirect(addOrgToPathIfNeeded(req, target));
return;
}
// The docAuth value will be cached from the getDoc() above (or could be derived from doc).
const docAuth = await dbManager.getDocAuthCached({userId, org: mreq.org, urlId});
assertAccess('viewers', docAuth);
} catch (err) {
if (err.status === 404) {
log.info("/:urlId/app.html did not find doc", mreq.userId, urlId, doc && doc.access, mreq.org);
throw new ApiError('Document not found.', 404);
} else if (err.status === 403) {
log.info("/:urlId/app.html denied access", mreq.userId, urlId, doc && doc.access, mreq.org);
// If the user does not have access to the document, and is anonymous, and we
// have a login system, we may wish to redirect them to login process.
if (isAnonymousUser(mreq) && forceLogin) {
// First check if anonymous user has access to this org. If so, we don't propose
// that they log in. This is the same check made in redirectToLogin() middleware.
const result = await dbManager.getOrg({userId: getUserId(mreq)}, mreq.org || null);
if (result.status !== 200) {
// Anonymous user does not have any access to this org, or to this doc.
// Redirect to log in.
return forceLogin(req, res, next);
}
}
throw new ApiError('You do not have access to this document.', 403);
}
throw err;
}
let body: DocTemplate;
let docStatus: DocStatus|undefined;
const docId = doc.id;
if (!useWorkerPool()) {
body = await gristServer.getDocTemplate();
} else {
// The reason to pass through app.html fetched from docWorker is in case it is a different
// version of Grist (could be newer or older).
// TODO: More must be done for correct version tagging of URLs: <base href> assumes all
// links and static resources come from the same host, but we'll have Home API, DocWorker,
// and static resources all at hostnames different from where this page is served.
// TODO docWorkerMain needs to serve app.html, perhaps with correct base-href already set.
const headers = {
Accept: 'application/json',
...getTransitiveHeaders(req),
};
const workerInfo = await getWorker(docWorkerMap, docId, `/${docId}/app.html`, {headers});
docStatus = workerInfo.docStatus;
body = await workerInfo.resp.json();
}
await sendAppPage(req, res, {path: "", content: body.page, tag: body.tag, status: 200,
googleTagManager: 'anon', config: {
assignmentId: docId,
getWorker: {[docId]: customizeDocWorkerUrl(docStatus?.docWorker?.publicUrl, req)},
getDoc: {[docId]: pruneAPIResult(doc as unknown as APIDocument)},
plugins
}});
});
// The * is a wildcard in express 4, rather than a regex symbol.
// See https://expressjs.com/en/guide/routing.html
app.get('/doc/:urlId([^/]+):remainder(*)', ...docMiddleware, docHandler);
app.get('/:urlId([^/]{12,})/:slug([^/]+):remainder(*)',
...docMiddleware, docHandler);
}
// Return true if document related endpoints are served by separate workers.
function useWorkerPool() {
return process.env.GRIST_SINGLE_PORT !== 'true';
}