(core) move home server into core

Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552

app/server/lib/sendAppPage.ts

@@ -0,0 +1,105 @@
+import {GristLoadConfig} from 'app/common/gristUrls';
+import {isAnonymousUser} from 'app/server/lib/Authorizer';
+import {RequestWithOrg} from 'app/server/lib/extractOrg';
+import {GristServer} from 'app/server/lib/GristServer';
+import * as express from 'express';
+import * as fse from 'fs-extra';
+import * as path from 'path';
+
+export interface ISendAppPageOptions {
+  path: string;        // Ignored if .content is present (set to "" for clarity).
+  content?: string;
+  status: number;
+  config: Partial<GristLoadConfig>;
+  tag?: string;        // If present, override version tag.
+
+  // If present, enable Google Tag Manager on this page (if GOOGLE_TAG_MANAGER_ID env var is set).
+  // Used on the welcome page to track sign-ups. We don't intend to use it for in-app analytics.
+  // Set to true to insert tracker unconditionally; false to omit it; "anon" to insert
+  // it only when the user is not logged in.
+  googleTagManager?: true | false | 'anon';
+}
+
+export function makeGristConfig(homeUrl: string|null, extra: Partial<GristLoadConfig>,
+                                baseDomain?: string, req?: express.Request
+): GristLoadConfig {
+  // .invalid is a TLD the IETF promises will never exist.
+  const pluginUrl = process.env.APP_UNTRUSTED_URL || 'plugins.invalid';
+  const pathOnly = (process.env.GRIST_ORG_IN_PATH === "true") ||
+    (homeUrl && new URL(homeUrl).hostname === 'localhost') || false;
+  const mreq = req as RequestWithOrg|undefined;
+  return {
+    homeUrl,
+    org: process.env.GRIST_SINGLE_ORG || (mreq && mreq.org),
+    baseDomain,
+    singleOrg: process.env.GRIST_SINGLE_ORG,
+    pathOnly,
+    supportAnon: shouldSupportAnon(),
+    pluginUrl,
+    stripeAPIKey: process.env.STRIPE_PUBLIC_API_KEY,
+    helpScoutBeaconId: process.env.HELP_SCOUT_BEACON_ID,
+    maxUploadSizeImport: (Number(process.env.GRIST_MAX_UPLOAD_IMPORT_MB) * 1024 * 1024) || undefined,
+    maxUploadSizeAttachment: (Number(process.env.GRIST_MAX_UPLOAD_ATTACHMENT_MB) * 1024 * 1024) || undefined,
+    timestampMs: Date.now(),
+    ...extra,
+  };
+}
+
+/**
+ * Send a simple template page, read from file at pagePath (relative to static/), with certain
+ * placeholders replaced.
+ */
+export function makeSendAppPage(opts: {
+  server: GristServer|null, staticDir: string, tag: string, testLogin?: boolean,
+  baseDomain?: string
+}) {
+  const {server, staticDir, tag, testLogin} = opts;
+  return async (req: express.Request, resp: express.Response, options: ISendAppPageOptions) => {
+    // .invalid is a TLD the IETF promises will never exist.
+    const config = makeGristConfig(server ? server.getHomeUrl(req) : null, options.config,
+      opts.baseDomain, req);
+
+    // We could cache file contents in memory, but the filesystem does caching too, and compared
+    // to that, the performance gain is unlikely to be meaningful. So keep it simple here.
+    const fileContent = options.content || await fse.readFile(path.join(staticDir, options.path), 'utf8');
+
+    const needTagManager = (options.googleTagManager === 'anon' && isAnonymousUser(req)) ||
+      options.googleTagManager === true;
+    const tagManagerSnippet = needTagManager ? getTagManagerSnippet() : '';
+    const staticOrigin = process.env.APP_STATIC_URL || "";
+    const staticBaseUrl = `${staticOrigin}/v/${options.tag || tag}/`;
+    const warning = testLogin ? "<div class=\"dev_warning\">Authentication is not enforced</div>" : "";
+    const content = fileContent
+      .replace("<!-- INSERT WARNING -->", warning)
+      .replace("<!-- INSERT BASE -->", `<base href="${staticBaseUrl}">` + tagManagerSnippet)
+      .replace("<!-- INSERT CONFIG -->", `<script>window.gristConfig = ${JSON.stringify(config)};</script>`);
+    resp.status(options.status).type('html').send(content);
+  };
+}
+
+function shouldSupportAnon() {
+  // Enable UI for anonymous access if a flag is explicitly set in the environment
+  return process.env.GRIST_SUPPORT_ANON === "true";
+}
+
+/**
+ * Returns the Google Tag Manager snippet to insert into <head> of the page, if
+ * GOOGLE_TAG_MANAGER_ID env var is set to a non-empty value. Otherwise returns the empty string.
+ */
+function getTagManagerSnippet() {
+  // Note also that we only insert the snippet for the <head>. The second recommended part (for
+  // <body>) is for <noscript> scenario, which doesn't apply to the Grist app (such visits, if
+  // any, wouldn't work and shouldn't be counted for any metrics we care about).
+  const tagId = process.env.GOOGLE_TAG_MANAGER_ID;
+  if (!tagId) { return ""; }
+
+  return `
+<!-- Google Tag Manager -->
+<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
+j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
+'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+})(window,document,'script','dataLayer','${tagId}');</script>
+<!-- End Google Tag Manager -->
+`;
+}