(core) Add new Grist sign-up page

Summary:
Available at login.getgrist.com/signup, the new sign-up page
includes similar options available on the hosted Cognito sign-up
page, such as support for registering with Google. All previous
redirects to Cognito for sign-up should now redirect to the new
Grist sign-up page.

Login is still handled with the hosted Cognito login page, and there
is a link to go there from the new sign-up page.

Test Plan: Browser, project and server tests.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3249

app/server/lib/FlexServer.ts

@@ -1,3 +1,4 @@
+import {ApiError} from 'app/common/ApiError';
 import {BillingTask} from 'app/common/BillingAPI';
 import {delay} from 'app/common/delay';
 import {DocCreationInfo} from 'app/common/DocListAPI';
@@ -40,7 +41,7 @@ import {IBilling} from 'app/server/lib/IBilling';
 import {IDocStorageManager} from 'app/server/lib/IDocStorageManager';
 import {INotifier} from 'app/server/lib/INotifier';
 import * as log from 'app/server/lib/log';
-import {getLoginSystem} from 'app/server/lib/logins';
+import {getLoginSubdomain, getLoginSystem} from 'app/server/lib/logins';
 import {IPermitStore} from 'app/server/lib/Permit';
 import {getAppPathTo, getAppRoot, getUnpackedAppRoot} from 'app/server/lib/places';
 import {addPluginEndpoints, limitToPlugins} from 'app/server/lib/PluginEndpoint';
@@ -237,6 +238,14 @@ export class FlexServer implements GristServer {
     return this.server ? (this.server.address() as AddressInfo).port : this.port;
   }
 
+  /**
+   * Get a url to an org that should be accessible by all signed-in users. For now, this
+   * returns the base URL of the personal org (typically docs[-s]).
+   */
+  public getMergedOrgUrl(req: RequestWithLogin, pathname: string = '/'): string {
+    return this._getOrgRedirectUrl(req, this._dbManager.mergedOrgDomain(), pathname);
+  }
+
   public getPermitStore(): IPermitStore {
     if (!this._internalPermitStore) { throw new Error('no permit store available'); }
     return this._internalPermitStore;
@@ -805,22 +814,50 @@ export class FlexServer implements GristServer {
     // should be factored out of it.
     this.addComm();
 
+    /**
+     * Gets the URL to redirect back to after successful sign-up or login.
+     *
+     * Note that in the test env, this will redirect further.
+     */
+    const getNextUrl = async (mreq: RequestWithLogin): Promise<string> => {
+      // If a "next" query param is present, check if it's safe to use, and return it if so.
+      const next = optStringParam(mreq.query.next);
+      if (next) {
+        if (!(await this._hosts.isSafeRedirectUrl(next))) {
+          throw new ApiError('Invalid redirect URL', 400);
+        }
+
+        return next;
+      }
+
+      // Otherwise, return the "/" path on the request host. If the host is the Grist
+      // login host, return the "/" path on the merged org instead.
+      const loginSubdomain = getLoginSubdomain();
+      return !loginSubdomain || mreq.org !== loginSubdomain ?
+        getOrgUrl(mreq) : this.getMergedOrgUrl(mreq);
+    };
+
     async function redirectToLoginOrSignup(
       this: FlexServer, signUp: boolean|null, req: express.Request, resp: express.Response,
     ) {
       const mreq = req as RequestWithLogin;
+
+      // If sign-up request is to the Grist login host, serve a sign-up page instead of redirecting.
+      const loginSubdomain = getLoginSubdomain();
+      if (signUp && loginSubdomain && mreq.org === loginSubdomain) {
+        return this._sendAppPage(req, resp, {path: 'login.html', status: 200, config: {}});
+      }
+
       // This will ensure that express-session will set our cookie if it hasn't already -
       // we'll need it when we come back from Cognito.
       forceSessionChange(mreq.session);
-      // Redirect to "/" on our requested hostname (in test env, this will redirect further)
-      const next = getOrgUrl(req);
       if (signUp === null) {
         // Like redirectToLogin in Authorizer, redirect to sign up if it doesn't look like the
         // user has ever logged in on this browser.
         signUp = (mreq.session.users === undefined);
       }
       const getRedirectUrl = signUp ? this._getSignUpRedirectUrl : this._getLoginRedirectUrl;
-      resp.redirect(await getRedirectUrl(req, new URL(next)));
+      resp.redirect(await getRedirectUrl(req, new URL(await getNextUrl(mreq))));
     }
 
     this.app.get('/login', expressWrap(redirectToLoginOrSignup.bind(this, false)));
@@ -899,10 +936,9 @@ export class FlexServer implements GristServer {
     this.app.get('/signed-out', expressWrap((req, resp) =>
       this._sendAppPage(req, resp, {path: 'error.html', status: 200, config: {errPage: 'signed-out'}})));
 
-    // Add a static "verified" page.  This is where an email verification link will land,
-    // on success.  TODO: rename simple static pages from "error" to something more generic.
+    // Add a static "verified" page.  This is where an email verification link will land, on success.
     this.app.get('/verified', expressWrap((req, resp) =>
-      this._sendAppPage(req, resp, {path: 'error.html', status: 200, config: {errPage: 'verified'}})));
+      this._sendAppPage(req, resp, {path: 'login.html', status: 200, config: {}})));
 
     const comment = await this._loginMiddleware.addEndpoints(this.app);
     this.info.push(['loginMiddlewareComment', comment]);
@@ -1127,8 +1163,7 @@ export class FlexServer implements GristServer {
         redirectPath = '/welcome/teams';
       }
 
-      const mergedOrgDomain = this._dbManager.mergedOrgDomain();
-      const redirectUrl = this._getOrgRedirectUrl(mreq, mergedOrgDomain, redirectPath);
+      const redirectUrl = this.getMergedOrgUrl(mreq, redirectPath);
       resp.json({redirectUrl});
     }),
     // Add a final error handler that reports errors as JSON.
@@ -1466,7 +1501,7 @@ export class FlexServer implements GristServer {
 
     // Redirect anonymous users to the merged org.
     if (!mreq.userIsAuthorized) {
-      const redirectUrl = this._getOrgRedirectUrl(mreq, this._dbManager.mergedOrgDomain());
+      const redirectUrl = this.getMergedOrgUrl(mreq);
       log.debug(`Redirecting anonymous user to: ${redirectUrl}`);
       return resp.redirect(redirectUrl);
     }

app/server/lib/GristServer.ts

@@ -4,6 +4,7 @@ import { Document } from 'app/gen-server/entity/Document';
 import { Organization } from 'app/gen-server/entity/Organization';
 import { Workspace } from 'app/gen-server/entity/Workspace';
 import { HomeDBManager } from 'app/gen-server/lib/HomeDBManager';
+import { RequestWithLogin } from 'app/server/lib/Authorizer';
 import * as Comm from 'app/server/lib/Comm';
 import { Hosts } from 'app/server/lib/extractOrg';
 import { ICreate } from 'app/server/lib/ICreate';
@@ -23,6 +24,7 @@ export interface GristServer {
   getHomeUrlByDocId(docId: string, relPath?: string): Promise<string>;
   getDocUrl(docId: string): Promise<string>;
   getOrgUrl(orgKey: string|number): Promise<string>;
+  getMergedOrgUrl(req: RequestWithLogin, pathname?: string): string;
   getResourceUrl(resource: Organization|Workspace|Document): Promise<string>;
   getGristConfig(): GristLoadConfig;
   getPermitStore(): IPermitStore;

app/server/lib/expressWrap.ts

@@ -29,8 +29,8 @@ const buildJsonErrorHandler = (options: JsonErrorHandlerOptions = {}): express.E
   return (err, req, res, _next) => {
     const mreq = req as RequestWithLogin;
     log.warn(
-      "Error during api call to %s: (%s) user %d%s%s",
-      req.path, err.message, mreq.userId,
+      "Error during api call to %s: (%s)%s%s%s",
+      req.path, err.message, mreq.userId !== undefined ? ` user ${mreq.userId}` : '',
       options.shouldLogParams !== false ? ` params ${JSON.stringify(req.params)}` : '',
       options.shouldLogBody !== false ? ` body ${JSON.stringify(req.body)}` : '',
     );

app/server/lib/extractOrg.ts

@@ -131,6 +131,27 @@ export class Hosts {
     return this._redirectHost.bind(this);
   }
 
+  /**
+   * Returns true if `url` either points to a native Grist host (e.g. foo.getgrist.com),
+   * or a custom host for an existing Grist org.
+   */
+  public async isSafeRedirectUrl(url: string): Promise<boolean> {
+    const {host, protocol} = new URL(url);
+    if (!['http:', 'https:'].includes(protocol)) { return false; }
+
+    switch (this._getHostType(host)) {
+      case 'native': { return true; }
+      case 'custom': {
+        const org = await mapGetOrSet(this._host2org, host, async () => {
+          const o = await this._dbManager.connection.manager.findOne(Organization, {host});
+          return o?.domain ?? undefined;
+        });
+        return org !== undefined;
+      }
+      default: { return false; }
+    }
+  }
+
   public close() {
     this._host2org.clear();
     this._org2host.clear();